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chris Sinfield

Joined: 28 Nov 2006
Posts: 270
Location: Sydney Australia

Posted: Mon Sep 06, 2010 3:38 am Post subject: dim able strip LED lighting

Hi all 

I was going to use the new Dim-able LED strip lighting for under the Inst combing for my NVFR aircraft



they come in red or blue. never really used blue before ??



Anyone used these yet?? do the dimmers come with the strip  LED's or do you have to buy them separately.

Chris

mdnanwelch7(at)hotmail.co
Guest

Posted: Mon Sep 06, 2010 6:01 am Post subject: dim able strip LED lighting

 

 	  Quote: 	
		   they come in red or blue. never really used blue before ??

 Chris


	


 Chris,

  

   Irrespective of the different colors of LEDs, you have to keep in mind

 specifically what you are using the LED for.

  

   Blue panel LEDs may look "cool" but they are NOT appropriate for use 

 as a night lighting.  Blue light is a shorter wavelength than red, and this

 aspect does not work as well for rapidly adjusting light/dark conditions

 as red.

  

   Red light has a longer wavelength than blue, and this phenomenon allows 

 the human eye to adjust quicker from a dark environment to a red lit 

 environment than blue lighting.

  

   This is the reason aircraft cockpit lighting is red.  When you look outside at

 night while flying, and then look back inside at the instruments, the red lit

 instruments don't mess up your vision (light receptors) as much as any other 

 color wavelength will.

  

 Mike Welch

 		 	   		    [quote][b]

sprocket(at)vx-aviation.c
Guest

Posted: Mon Sep 06, 2010 7:52 am Post subject: dim able strip LED lighting

Here's an interesting article http://stlplaces.com/night_vision_red_myth/.

  

 In my cockpit, I only use low-level white dimmable  lighting for the express purpose of reading charts at night.  Charts  require white light in order to see all of the colors.  When not reading  charts, all of the modern instruments have their own back-lights, which are kept  dim.  Looks like red flood lighting is useful for general night  lighting.

  

 Vern 

  



  From: Mike Welch (mdnanwelch7(at)hotmail.com) 

 Sent: Monday, September 06, 2010 6:17 AM

 To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)  

 Subject: RE: dim able strip LED  lighting

 



 

 	  Quote: 	
		   they come in red or blue. never really used blue  before ??

 Chris


	


Chris,

 

  Irrespective of the  different colors of LEDs, you have to keep in mind

specifically what you are  using the LED for.

 

  Blue panel LEDs may look "cool" but they  are NOT appropriate for use 

as a night lighting.  Blue light is a  shorter wavelength than red, and this

aspect does not work as well for  rapidly adjusting light/dark conditions

as red.

 

  Red light  has a longer wavelength than blue, and this phenomenon allows 

the human eye  to adjust quicker from a dark environment to a red lit 

environment than blue  lighting.

 

  This is the reason aircraft cockpit lighting is  red.  When you look outside at

night while flying, and then look back  inside at the instruments, the red lit

instruments don't mess up your vision  (light receptors) as much as any other 

color wavelength  will.

 

Mike Welch



   [quote][b]

RV7ASask

Joined: 25 Jan 2006
Posts: 36

Posted: Mon Sep 06, 2010 8:06 am Post subject: Re: dim able strip LED lighting

I have installed a strip of white dimable LEDs above my switches. They work great! The strip happens to be 3/8 in wide and fit perfectly into an aluminum channel integrated at the bottom of the panel. I would agree with Vern. Stick with white.  The dimmer is available from Spruce.



http://www.aircraftspruce.ca/catalog/elpages/pwmDimmer.php



David

tim2542(at)sbcglobal.net
Guest

Posted: Mon Sep 06, 2010 8:45 am Post subject: dim able strip LED lighting

According  Stein-air’s web site Blue is now the standard color on commercial and military aircraft….FWIW  

Tim Andres  

     

 (rnbraud(at)yahoo.com)   

        

  

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Mike Welch

 Sent: Monday, September 06, 2010 6:17 AM

 To: aeroelectric-list(at)matronics.com

 Subject: RE: AeroElectric-List: dim able strip LED lighting  

  

   

 

 > they come in red or blue. never really used blue before ??

 > Chris

 

 Chris,

  

   Irrespective of the different colors of LEDs, you have to keep in mind

 specifically what you are using the LED for.

  

   Blue panel LEDs may look "cool" but they are NOT appropriate for use 

 as a night lighting.  Blue light is a shorter wavelength than red, and this

 aspect does not work as well for rapidly adjusting light/dark conditions

 as red.

  

   Red light has a longer wavelength than blue, and this phenomenon allows 

 the human eye to adjust quicker from a dark environment to a red lit 

 environment than blue lighting.

  

   This is the reason aircraft cockpit lighting is red.  When you look outside at

 night while flying, and then look back inside at the instruments, the red lit

 instruments don't mess up your vision (light receptors) as much as any other 

 color wavelength will.

  

 Mike Welch   	  Quote: 	
		    http://www.matronics.com/Navigator?AeroElectric-List 	
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     No virus found in this incoming message. Checked by AVG - www.avg.com  271.1.1/3117 - Release Date: 09/05/10 23:35:00  [quote][b]

riggs_la(at)yahoo.com
Guest

Posted: Mon Sep 06, 2010 12:34 pm Post subject: dim able strip LED lighting

White is not good for your night vision.  The military has found that a

blue-green light is the best in night operations.



Lynn



--

gerry.vandyk(at)shaw.ca
Guest

Posted: Mon Sep 06, 2010 3:46 pm Post subject: dim able strip LED lighting

That is rather curious.  Amateur astronomers use red flashlights at night

when looking at their charts, the reason being red light doesn't cause the

eye's iris to close, which kills dark adapted vision.  When observing

objects through larger telescopes one can occasionally pick up a blue-green

color in subjects like the Ring Nebula (M57)the reason being the color

receptors in the retina pick up the middle of the visible spectrum (520

nanometer wavelength)at the lowest light levels.  I have a suspicion that

this study determined that blue-green is the easiest to see, which is

different than the best color for preserving night vision.



http://www.oneminuteastronomer.com/astro-course-day-5/



I would suggest doing some research into WWII night fighters.  For one, the

P-61 Black Widow used red cockpit lighting.  Red allows you to look at the

instruments, then look out the window without having to wait for your eyes

to re-adapt to the darkness.



Gerry



--

mdnanwelch7(at)hotmail.co
Guest

Posted: Mon Sep 06, 2010 4:36 pm Post subject: dim able strip LED lighting

 

 	  Quote: 	
		   That is rather curious. Amateur astronomers use red flashlights at night

 when looking at their charts, the reason being red light doesn't cause the

 eye's iris to close, which kills dark adapted vision. 

 > Red allows you to look at the
	


 	  Quote: 	
		   instruments, then look out the window without having to wait for your eyes

 to re-adapt to the darkness.

 

 Gerry


	


 Gerry,

  

   This tendency of the red light not affecting the iris' closing, was what I getting at.

 You offered more detail than me, and you're correct.  I think that this is also why darkrooms 

 for developing film are lit with red lights.

  

   My Cessna(s) had red cockpit lighting.  Like I said initially, you have to determine the

 primary purpose of the LED lighting.  If you want to see things inside the cockpit, and

 not screw up your night vision, use red.  If you want to be able to see something very

 well in the dark, like an instrument, use blue/green lighting (and you can turn down the 

 brightness a lot).

  

 Mike Welch

  

  

 		 	   		    [quote][b]

n8zg(at)ATT.NET
Guest

Posted: Mon Sep 06, 2010 5:59 pm Post subject: dim able strip LED lighting

Ummm… No.  

   

Darkroom lamps  are red because black & white photo paper will tolerate low levels of red light – film will not tolerate ANY light.  I’ll suggest that red light in the cockpit descended from the photo world, where folks had been working in very low light levels for many decades before there were lights in airplanes…  

   

Working in a darkroom will give you a completely different perspective on the red-light/night-blind transition.  We go from low-intensity red ambient to low intensity white (enlarger lamp on to set-up, crop the print, then starring into the lamp with a mirror to focus the lens) to room light and back to low-intensity red in a matter of seconds.  Given that experience, I’ve never given much credence to the night-vision and red-light argument.  Unless I’m slapped right in the face with a LOT of light that dazzles the retinas (close, exceptionally bright landing lights?), I find I’m very tolerant of cockpit light levels, and the transition from inside reading charts and gauges to outside looking at stars and horizons is uneventful.  

   

Neal  

RV-7 N8ZG (all the loose ends)  

CherokeeJet N9586J  

   

===============    

   

I think that this is also why darkrooms for developing film are lit with red lights.

   

 Mike Welch

 

   [quote] [b]

email(at)jaredyates.com
Guest

Posted: Mon Sep 06, 2010 6:15 pm Post subject: dim able strip LED lighting

This is an interesting dimmer.  Does it have the noise problems that Bob was writing about?



On Mon, Sep 6, 2010 at 12:06 PM, RV7ASask <rv7alamb(at)sasktel.net (rv7alamb(at)sasktel.net)> wrote:

 [quote]--> AeroElectric-List message posted by: "RV7ASask" <rv7alamb(at)sasktel.net (rv7alamb(at)sasktel.net)>

  

 I have installed a strip of white dimable LEDs above my switches. They work great! The strip happens to be 3/8 in wide and fit perfectly into an aluminum channel integrated at the bottom of the panel. I would agree with Vern. Stick with white.  The dimmer is available from Spruce.

  

 http://www.aircraftspruce.ca/catalog/elpages/pwmDimmer.php

 

 David

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=311539#311539

 

 

 

 

 

 

 

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 -List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

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 http://forums.matronics.com

 ===========

 le, List Admin.

 ="_blank">http://www.matronics.com/contribution

 ===========

 

 

 

 [b]

riggs_la(at)yahoo.com
Guest

Posted: Mon Sep 06, 2010 6:37 pm Post subject: dim able strip LED lighting

I have flown with both, I am a retired Army pilot, and can tell you that the

blue-green lighting has less of an impact on night vision than red and is

easier to read charts with.  At lease the blue-green the Army used.



Lynn



--

RV7ASask

Joined: 25 Jan 2006
Posts: 36

Posted: Mon Sep 06, 2010 7:04 pm Post subject: Re: dim able strip LED lighting

>>This is an interesting dimmer. ï¿½Does it have the noise problems that Bob was writing about?



I am just finishing installing the radios so I can't tell you about noise problems at this time. More to follow.



Weighing in on the color of the light. I said earlier 'Stick with White.' I think both Mr Boeing and Mr Airbus have opted for white in the cockpit and I think they got it right.



David

rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Tue Sep 07, 2010 5:41 am Post subject: dim able strip LED lighting

Using the example of Boeing and Airbus for cockpit lighting in a good example of not examining the application before making a decision, IMHO. When was the last time an airline crew really needed to have good night vision for looking outside the cockpit? Unless you plan on flying on instruments from takeoff to touchdown, or very nearly, is this the wise choice? Even using the military, particularly what the helicopter cockpits use, is questionable since their decision may have been driven as much by compatibility with night vision equipment as the human eye.

Just exactly how much improvement is blue/green over red? Does the difference amount to anything more that picking the fly poop from the pepper, or are we dealing with an unquantifiable "coolness factor"?

 



Rick Girard



On Mon, Sep 6, 2010 at 10:04 PM, RV7ASask <rv7alamb(at)sasktel.net (rv7alamb(at)sasktel.net)> wrote:

 	  Quote: 	
		   --> AeroElectric-List message posted by: "RV7ASask" <rv7alamb(at)sasktel.net (rv7alamb(at)sasktel.net)>

 

 >>This is an interesting dimmer. ï¿½Does it have the noise problems that Bob was writing about?

 

 I am just finishing installing the radios so I can't tell you about noise problems at this time. More to follow.

 

 Weighing in on the color of the light. I said earlier 'Stick with White.' I think both Mr Boeing and Mr Airbus have opted for white in the cockpit and I think they got it right.

 

 David

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=311626#311626

 

 

 

 

 

 

 

 ===========

  -

 ric-List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

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 ===========

 e -

  Â  Â  Â  Â  Â -Matt Dralle, List Admin.

 t="_blank">http://www.matronics.com/contribution

 ===========

 

 

 

 	


-- 

Zulu Delta

Kolb Mk IIIC

582 Gray head

4.00 C gearbox

3 blade WD

Thanks, Homer GBYM

It is not bigotry to be certain we are right; but it is bigotry to be unable to imagine how we might possibly have gone wrong.

 Â -Â G.K. Chesterton



 

  [quote][b]

_________________
The smallest miracle right in front of you is enough to make you happy....

blackoaks(at)gmail.com
Guest

Posted: Tue Sep 07, 2010 6:55 am Post subject: dim able strip LED lighting

And remember when the red cockpit lighting made all of the fan markers and LF ranges mysteriously disappear from our charts on night flights!



On Mon, Sep 6, 2010 at 7:25 PM, Lynn Riggs <riggs_la(at)yahoo.com (riggs_la(at)yahoo.com)> wrote:

 [quote]--> AeroElectric-List message posted by: "Lynn Riggs" <riggs_la(at)yahoo.com (riggs_la(at)yahoo.com)>

  

 

I have flown with both, I am a retired Army pilot, and can tell you that the

 blue-green lighting has less of an impact on night vision than red and is

 easier to read charts with.  At lease the blue-green the Army used.

 

 Lynn

 

 --

jimw_btg(at)earthlink.net
Guest

Posted: Tue Sep 07, 2010 6:55 am Post subject: dim able strip LED lighting

Jim Wickert here, I have been following this thread and have the following to put up for added fodder.Â  We have a Government Marine contract which we are working on that has a section for Night Illumination of Instrumentation and we are doing the scope research now. Below is some interesting information and food for thought.Â  At this time our general consensus is Soft White Flood of panels?Â  We have not released our findings to our customer however.Â  Take care sorry for the amount of text but this is only a snip of the 13 page findings.Â    

   

FLITELite Light Color, Intensity & Night Vision:  

Pilots have a choice of FLITELite colors - NVIS White (more information on NVIS White), Soft White that is NVIS friendly, Green, Red and Blue. The best light choice is NVIS White, followed by soft white, for a light that will protect your central night vision and provide full spectrum light. Green and Blue will protect central night vision as well, but blues and greens will disappear with this color of light - something for a pilot to consider prior to use. Red is also available, which will protect peripheral night vision, but not central vision as well as the soft white, blue and green. Red's on charts will also not be visible with red light, another consideration for the pilot to consider when making a color choice.   

The eyes are comprised of Rods and Cones. We hear people talk about Rods being for night vision, and Cones for day vision, and while they both have their special attributes, it would be better to classify them in the aviation environment at Peripheral (Rods) and Central (Cones) vision. Both rods and cones have a day and night mode, and they both react to light at different rates, and to have sensitivity to different light frequencies.  

Rods surround the periphery of the eye and are used for peripheral vision, and night vision. They do not see color, and do not detect motion. Rods only provide non-color vision at an acuity of 20/200. Rods are most susceptible to blue light. You never read, or scan your instruments with your Rods - or your peripheral vision - think about it. You are reading this article with your central vision - your cones.   

Cones are used for color, central vision, with visual acuity of 20/20. The cones have a focal width of approximately 20 to 30 degrees. Cones are most susceptible to red light.  

Cones are used when you read, day or night. During the day we read with our cones - during the night we need a light to read - obvious, but it shatters the red light myth in the aviation cockpit.  

[img]cid:image001.gif(at)01CB4E6E.14CD7790[/img]  

So the question is what is the best light that will provide your eyes, and brain with the best light for reading? The answer is a dim white light. Look inside any of the new jets, and you will find that the lighting is white. Military cockpits specify NVIS White. NVIS White appears to have a green tint, but it is a full spectrum light. More on NVIS Compatibility   

FLITELite is set to a 25 degree field of view to maximize the physiology of the pilotâ€™s eye. But to preserve night vision the intensity of the light is what matters. By using a full spectrum white light, the full spectrum light and low reflection reduces the amount of light needed. The 25 degree field is critical to keep the light out of our peripheral vision so we can look for traffic, and gauge height when we are making that perfect night landing.   

Under red light, magenta symbols disappear on charts, and during electrical failures, red markings on instruments and gauges are unreadable. Blue light will make Blue 100LL fuel disappear.   

Unaided night vision even now in the 21st century is still the subject of some controversy.  

For those just looking for an executive answer as to what supplemental lighting should be used to reduced the recovery time back to night vision (dark adapted or scotopic) here it is: a fully dimmable white light! This of course is a very incomplete answer but so are the answers red or blue-green and you should know why.  

Letâ€™s start with red, specifically what I will call the red light myth.  

I believe the myth started in the photographic darkroom.  

Until about 1906 most photosensitive material (plate, film, and paper) was not very sensitive to red.  Some of these orthochromatic materials are still used. This allowed these materials to be dealt with for a short time under a relative bright red light because the human eye can see red if the level is bright enough. The fact that L.E.D.s (having a number of advantages over other light sources) were economically only available in red for some time has also help to perpetuate this myth.  

As more research about the eye was done it was found that the structure responsible for very low light vision, the rods, were also not very sensitive to red.  

It was assumed then that like film you could use red light, which is seen by the red sensitive cones (there are also blue and green sensitive cones to give color vision), without affecting the rods.  

It takes a while for true night vision to be recovered.  About 10 minutes for 10%, 30-45 minutes for 80%, the rest may take hours, days, or a week. The issue is the chemical in the eye, rhodopsin - commonly called visual purple, is broken down quickly by light.  The main issue then is intensity; color is only an issue because the rods (responsible for night vision) are most sensitive at a particular color. That color is a blue-green (507nm) similar to traffic light green (which is this color for a entirely different reason). It would seem that using the lowest brightness (using this color) additional light needed for a task is the best bet to retain this dark adaptation because it allows rods to function at their best.  

Unfortunately there are a number of drawbacks using only night vision.  

Among these are:     The inability to distinguish colors.   
No detail can be seen (about the same as 20/200      vision in daylight).   
That nothing can be seen directly in front of the      eyes (no rods in the center of the retina), you must learn to look about      15-20Â° off center.   
Only motion can be detected well, therefore you      may have to learn to move your eyes to detect something that doesn't move.        
Objects that aren't moving appear to move      (autokinesis).  This has probably led to a number of plane crashes.    

If you need to see directly in front of you or see detail you need red.  Like many myths the red light myth has some basis in fact.  The red truth?  

Why red?  The center 1.5% of your retina (the fovea) which provides you with most detailed vision is packed almost exclusively with red sensitive cones.  

This is the same area that has no rods and is responsible for the night blind spot.  There are fewer total green sensitive cones than red.  The number of blue sensitive cones is very small compared to green and red.  

Which is just as well since the lens in the human eye cannot focus red and blue at the same time.  And using green really only changes perceived brightness because of the way the signals are processed in our neural pathways. Unlike a digital camera, more pixels, in this case, doesn't give us more detail.  

                                                    <![endif]--><![if !vml]>[img]cid:image002.gif(at)01CB4E6E.8A036B00[/img]<![endif]>Chart showing the distribution of rods vs cones.  Note the absence of rods in the center and the absence of both about 15Â° away from the the center toward the nose where the optic nerve passes.  

At first glance the tendency would be to pick the hue of red at which we are most sensitive (566nm) which would make sense except for the real reason: we don't want to involve the rods.  The reason is the rods share the neural pathways with the cones so that you have this fuzzy image overriding the detailed one.  This effect disappears at slightly higher mesopic levels which is why white is a good choice for most tasks.  Many people look at the numbers for sensitivity for rods and cones and forget that in most cases the numbers have been adjusted so that rod peek sensitive matches cone peak.  Rods are in fact sensitive well into the infrared (not too useful except to know that light you can barely sense can adversely impact your night vision).  The key then is finding a hue that we can have at a high enough intensity that we can see the detail we need without activating our rods to the point where they obscure that detail.  Most source say this should be nothing shorter than 650nm.  Experimentation shows a L.E.D. with a peek around 700nm seems to work best (perceived as a deep red).  Note that red may be fatiguing to the eyes.  

Conclusions:     No matter what your color choice it must be fully      adjustable for intensity.   
If you need the fastest dark adaptation recovery      and can adjust to the limitations, or everyone in your group is using      night vision equipment then blue-green.   
If you must see detail (reading a star chart, or      instrument settings) and can lose peripheral vision (see note 1),      then a very long wavelength red at a very low level.  Red really only      has an advantage at very low levels (were the night blind spot is very      obvious).   
A general walking around light so that you don't      trip over the tripod, knock over equipment or bump into people, then      blue-green with enough red added to get rid of the night blind spot, or      maybe just use white.  Blue-green at higher brightness also works      very well and at a lower intensity than white.   
If you need to see color and detail then likely      the best choice is the dimmest white light for the shortest amount of      time.   
If you are in the military you must follow their      rules; hopefully they will have a good course in unassisted night vision.   
If you are a pilot and say you only fly in the      day, you should be aware of the problems of night vision and should      consider a basic (ground) course in night flying.   
If you wonder why no one else has drawn these      conclusions look at the dashboard of most cars.  The markings are large,      the pointers are large and an orange-red (a compromise, for certain      "color blind" persons) and at night it is edge lit with      blue-green filtered fully intensity adjustable light.    

For Best night vision:    Be sure you are getting enough vitamin A or its precursor      beta-carotene in your diet (needed for the visual purple).   
Green leafy stuff is best followed by vegetables      that have an orange color.  Yes that includes carrots but spinach or      dark leaf lettuce are better.  It is possible to get too much vitamin      A especially as a supplement.   
Keep up your general health.  Smoking is      also very bad for night vision, as are most illegal drugs and some      prescription drugs.   
Keep you blood sugar level as even as      possible.  No meal skipping.  Six small meals are better than      three large meals.  For carbohydrates favor starches (potatoes, rice,      and bread) over simple sugars (sweets, alcohol).   
Use dark neutral gray sunglasses, that pass no      more that 15% in full sun, when outside during the day.    

True night blindness is rare.  Most of what people call night blindness is either a lack of vitamin A in the diet or a failure to understand the night blind spot.  

Cataracts, even minor ones, increase the effects of glare at night and the eye's lens does yellow and passes less light as we age which may contribute to what some call night blindness.  

Note:  The red filtered light at the intensity most people use is likely decreasing night vision much more than a properly dimmed white or blue-green light would!  

Note:  There are day blind spots also but are in a different position in each eye so are less of a problem.  

Note:  Blue-green (also called cyan, turquoise, teal and other names) as used here is NOT the combination of two colors but is a single particular hue.  I use the most common name for that hue.  

           

Mil-STD 1472F   5.8.2.2 (table XVI) display lighting             

          

Brightness of   markings         

              

Condition of use         

Lighting Technique *         

cd/m2         

foot-lamberts         

Brightness Adjustment             

              

Indicator reading, dark adaptation necessary         

Red flood, indirect, or both, with operator choice         

0.07-0.35         

(0.02-0.1)         

Continuous throughout range             

              

Indicator reading, dark adaptation not necessary but   desirable         

Red or low-color-temperature white flood, indirect, or   both, with operator choice         

0.07-3.5â€          

(0.02-1.0)         

Continuous throughout range             

              

Indicator reading, dark adaptation not necessary         

White flood         

3.5-70         

(1-20)         

Fixed or continuous             

              

Panel monitoring, dark adaptation necessary         

Red edge lighting, red or white flood, or both, with   operator choice         

0.07-3.5         

(0.02-1.0)         

Continuous throughout range             

              

Panel monitoring, dark adaptation not necessary         

White flood         

35-70         

(10-20)         

Fixed or continuous             

              

Possible exposure to bright flashes, restricted daylight         

White flood         

35-70         

(10-20)         

Fixed             

              

Chart reading, dark adaptation necessary         

Red or white flood with operator choice         

0.35-3.50         

(0.1-1.0)         

Continuous throughout range             

              

Chart reading, dark adaptation not necessary         

White flood         

17-70         

(5-20)         

Fixed or continuous             

 

                 

* Where detection of ground vehicles or other protected   assets by image intensifier night vision devices must be minimized,   blue-green light (incandescent filament through a filter which passes only   wave lengths shorter than 600 nm) should be used in lieu of red light.             

              

â€  Possible error in original, read as: 0.07-0.35, likely   occurred when converted to metric.            

  

This is intended only as an overview; no warranty of this information is expressed or implied      

  

[Update 17 Nov 2003] I find new myths are springing up.  Such as blue-green L.E.D.s are emitting two colors of light.  This is a mis-understanding of the color name and that this is the most accepted name for this one color.  Another is that blue improves night vision.  While at somewhat higher levels it, of course, is stimulating the rods.  It is not an optimum color.  Another long standing myth is that human visual perception is based on three colors when it is really based on four.  The rods are usually ignored because many people believe, wrongly, that at the brightness at which we perceive color the rods are no longer providing our brains with any information. In fact the perception of brightness is highly influenced by the rods well into the photopic (bright light) range of vision.  Fluorescent lamp manufacturers have used this knowledge for a long time.  "Cool White" lamps have an additional amount of green phosphor added to make us "see" them as being brighter!  Of course the whole subject of color vision and the variances thereof (wrongly called "color blindness") will require a number of new pages even in synopsis form. 

 A point I forgot to cover is that to help preserve night vision in one eye the other may be closed or covered if you know you are about to be exposed to a brighter light, such as from a oncoming vehicle.  For normal observation both eyes should be kept open.  If it is difficult to concentrate on the desired image the eye not being used may be covered but not closed.  Closing affects focus and possibly acuity. 

 

 [Update 14 Dec 2003] A very important point barely mentioned in the original is that human peripheral vision is almost completely rod based!  The implication then is that we cannot see color at the edges of our vision.  If you think we can, try this simple experiment.  You will need a small assortment of color cards (try sheets of construction paper) and someone to assist you.  Sit looking straight ahead while youâ€™re assistant, about 6 to 10 feet away, slowly moves a random color card into the margin of your vision.  Now, while still looking straight ahead, what color is the card? 

 

 This is the second most important factor that has been ignored in the design of outdoor lighting, the first being glare!  However this study (in pdf), at the U. S. Dept. of Transportation, is a subjective study of blue tinted headlamps.

 

 [Update 23 Jan 2004] A few random notes to be better integrated into this document later.

 Luminances are approximate and will vary with the individual and conditions.

 Vision luminance rage 1 * 10-6 to 1 * 106 cd/M2

 Rods luminance rage 1 * 10-6 to 1 * 103 cd/M2 (may still play a roll above this range)

 Cones luminance rage 1 * 10-3 to 1 * 106 cd/M2

 Explain "Purinke shift"

 20/20 vision is the ability to resolve 1 minute of arc at 20 feet.

 Discuss Ricco's Law.

 Discuss afterimages.  

LITELite NVIS Compatibility   

MIL-STD-3009 was developed by the Department of Defense in February 2001 and superceded MIL-L-85762A. It specifies that NVIS White for crew cockpit and utility lighting. NVIS Green A is grand fathered into the cockpit for certain applications, but not for new applications.   

The chromacity of NVIS White makes it a full spectrum light even though is appears to have a green tint. Visible light can be split into the three primary colors, red, green and blue. The eye needs two primary colors to see 'white'. NVIS White, in simple terms is blue range through the green range. NVIS goggles filters allow a thin band of green light though the lens - so that users can see heads up displays and other required applications through the goggles.  

The level of light with respect to the chromacity is important due to this leak (filter) in the goggles. Other manufacturers claim to be the 'only authorized' lights produced since they meet a request for proposal standard. These claims are false - they have never tested FLITELite products how could they know? FLITELite meets and exceeds non-binding RFP standards, AND meets the modern, more stringent MIL-STD-3009, which is a binding requirement specified by the military.  

General Aviation pilots can benefit from this technology. This light spectrum and intensity is perfect for general night vision use as well.   

Read MIL-STD-3009 here.   

[img]cid:image003.jpg(at)01CB4E70.549CD8A0[/img]  

[img]cid:image004.jpg(at)01CB4E70.549CD8A0[/img]  

FLITELite minimizes the crossover zone by using a special combination of LED's and Filter material. The filter material ensures that the light greater than 600 nm is not transmitted.   

[img]cid:image005.jpg(at)01CB4E70.549CD8A0[/img]  

   

   

Jim Wickert  

Vision #159 â€œVision some will have some will notâ€  

Tel 920-467-0219  

Cell 920-912-1014  

     

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Richard Girard

 Sent: Tuesday, September 07, 2010 8:35 AM

 To: aeroelectric-list(at)matronics.com

 Subject: Re: Re: dim able strip LED lighting  

  

   

Using the example of Boeing and Airbus for cockpit lighting in a good example of not examining the application before making a decision, IMHO. When was the last time an airline crew really needed to have good night vision for looking outside the cockpit? Unless you plan on flying on instruments from takeoff to touchdown, or very nearly, is this the wise choice?    

Even using the military, particularly what the helicopter cockpits use, is questionable since their decision may have been driven as much by compatibility with night vision equipment as the human eye.  

    

Just exactly how much improvement is blue/green over red? Does the difference amount to anything more that picking the fly poop from the pepper, or are we dealing with an unquantifiable "coolness factor"?  

    

   

    

Rick Girard    

On Mon, Sep 6, 2010 at 10:04 PM, RV7ASask <rv7alamb(at)sasktel.net (rv7alamb(at)sasktel.net)> wrote:  

--> AeroElectric-List message posted by: "RV7ASask" <rv7alamb(at)sasktel.net (rv7alamb(at)sasktel.net)>

 

 >>This is an interesting dimmer. ï¿½Does it have the noise problems that Bob was writing about?

 

 I am just finishing installing the radios so I can't tell you about noise problems at this time. More to follow.

 

 Weighing in on the color of the light. I said earlier 'Stick with White.' I think both Mr Boeing and Mr Airbus have opted for white in the cockpit and I think they got it right.

 

 David

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=311626#311626

 

 

 

 

 

 

 

 ===========

 -

 ric-List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

 ===========

 MS -

 k">http://forums.matronics.com

 ===========

 e -

          -Matt Dralle, List Admin.

 t="_blank">http://www.matronics.com/contribution

 ===========

 

 

   

  



  

 --     

Zulu Delta  

    

Kolb Mk IIIC  

    

582 Gray head  

    

4.00 C gearbox  

    

3 blade WD  

    

Thanks, Homer GBYM  

    

   

    

It is not bigotry to be certain we are right; but it is bigotry to be unable to imagine how we might possibly have gone wrong.  

    

 - G.K. Chesterton  

    

   

  

   

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riggs_la(at)yahoo.com
Guest

Posted: Tue Sep 07, 2010 6:57 am Post subject: dim able strip LED lighting

Your point with the white light in the Airbus is quite valid.Â  As to the NVG compatibility, when flying with NVGâ€™s the cockpit lighting is turndown so low you cannot read your instrument without using the NVGâ€™s and color does not make much difference.Â  The Army was looking for a different lighting in the cockpit because the red lighting gave off an IR signature which is not good.Â  They found that the blue-green light was preferred buy their pilots, especially the older pilots, Â and did not give off an IR signature.Â  I have over 600 hours of flight time at night and a lot of that flying low level or terrain flight in VFR conditions with about 60 hours using the blue-green lighting which I thought to be much better than the red lighting.Â  I would not use white lighting in the cockpit for night VFR flight.Â  The problem I have found is the blue-green cockpit lighting is not available.  

   

Lynn  

   

   

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Richard Girard

 Sent: Tuesday, September 07, 2010 8:35 AM

 To: aeroelectric-list(at)matronics.com

 Subject: Re: Re: dim able strip LED lighting  

   

Using the example of Boeing and Airbus for cockpit lighting in a good example of not examining the application before making a decision, IMHO. When was the last time an airline crew really needed to have good night vision for looking outside the cockpit? Unless you plan on flying on instruments from takeoff to touchdown, or very nearly, is this the wise choice?    

Even using the military, particularly what the helicopter cockpits use, is questionable since their decision may have been driven as much by compatibility with night vision equipment as the human eye.  

    

Just exactly how much improvement is blue/green over red? Does the difference amount to anything more that picking the fly poop from the pepper, or are we dealing with an unquantifiable "coolness factor"?  

    

   

    

Rick Girard    

On Mon, Sep 6, 2010 at 10:04 PM, RV7ASask <rv7alamb(at)sasktel.net (rv7alamb(at)sasktel.net)> wrote:  

--> AeroElectric-List message posted by: "RV7ASask" <rv7alamb(at)sasktel.net (rv7alamb(at)sasktel.net)>

 

 >>This is an interesting dimmer. ï¿½Does it have the noise problems that Bob was writing about?

 

 I am just finishing installing the radios so I can't tell you about noise problems at this time. More to follow.

 

 Weighing in on the color of the light. I said earlier 'Stick with White.' I think both Mr Boeing and Mr Airbus have opted for white in the cockpit and I think they got it right.

 

 David

 

 

 

   

  

  [quote] [b]

AV8ORJWC

Joined: 13 Jul 2006
Posts: 1149
Location: Aurora, Oregon "Home of VANS"

Posted: Tue Sep 07, 2010 8:06 am Post subject: dim able strip LED lighting

Excellent research material.  I work on Part 121 Airliners and your below post seems consistent with what is being done up in their cockpits (Flight decks).  My darkroom days are way in the past and images of the damage of red light left too long on either film or paper are still remembered as damaging.

  

 Being able to dim the intensity and use of the most pleasing hue seem important to me.  Thank You.  Hope your Marine contract serves you well.

  



  John Cox

  

 do not archive



 

  From: owner-aeroelectric-list-server(at)matronics.com on behalf of Jim Wickert

Sent: Tue 9/7/2010 7:51 AM

To: aeroelectric-list(at)matronics.com

Subject: RE: Re: dim able strip LED lighting

   

Jim Wickert here, I have been following this thread and have the following to put up for added fodder.  We have a Government Marine contract which we are working on that has a section for Night Illumination of Instrumentation and we are doing the scope research now. Below is some interesting information and food for thought.  At this time our general consensus is Soft White Flood of panels?  We have not released our findings to our customer however.  Take care sorry for the amount of text but this is only a snip of the 13 page findings.   

  

FLITELite Light Color, Intensity & Night Vision: 

Pilots have a choice of FLITELite colors - NVIS White (more information on NVIS White), Soft White that is NVIS friendly, Green, Red and Blue. The best light choice is NVIS White, followed by soft white, for a light that will protect your central night vision and provide full spectrum light. Green and Blue will protect central night vision as well, but blues and greens will disappear with this color of light - something for a pilot to consider prior to use. Red is also available, which will protect peripheral night vision, but not central vision as well as the soft white, blue and green. Red's on charts will also not be visible with red light, another consideration for the pilot to consider when making a color choice.  

The eyes are comprised of Rods and Cones. We hear people talk about Rods being for night vision, and Cones for day vision, and while they both have their special attributes, it would be better to classify them in the aviation environment at Peripheral (Rods) and Central (Cones) vision. Both rods and cones have a day and night mode, and they both react to light at different rates, and to have sensitivity to different light frequencies. 

Rods surround the periphery of the eye and are used for peripheral vision, and night vision. They do not see color, and do not detect motion. Rods only provide non-color vision at an acuity of 20/200. Rods are most susceptible to blue light. You never read, or scan your instruments with your Rods - or your peripheral vision - think about it. You are reading this article with your central vision - your cones.  

Cones are used for color, central vision, with visual acuity of 20/20. The cones have a focal width of approximately 20 to 30 degrees. Cones are most susceptible to red light. 

Cones are used when you read, day or night. During the day we read with our cones - during the night we need a light to read - obvious, but it shatters the red light myth in the aviation cockpit. 

[img]image001.gif[/img] 

So the question is what is the best light that will provide your eyes, and brain with the best light for reading? The answer is a dim white light. Look inside any of the new jets, and you will find that the lighting is white. Military cockpits specify NVIS White. NVIS White appears to have a green tint, but it is a full spectrum light. More on NVIS Compatibility  

FLITELite is set to a 25 degree field of view to maximize the physiology of the pilot’s eye. But to preserve night vision the intensity of the light is what matters. By using a full spectrum white light, the full spectrum light and low reflection reduces the amount of light needed. The 25 degree field is critical to keep the light out of our peripheral vision so we can look for traffic, and gauge height when we are making that perfect night landing.  

Under red light, magenta symbols disappear on charts, and during electrical failures, red markings on instruments and gauges are unreadable. Blue light will make Blue 100LL fuel disappear.  

Unaided night vision even now in the 21st century is still the subject of some controversy. 

For those just looking for an executive answer as to what supplemental lighting should be used to reduced the recovery time back to night vision (dark adapted or scotopic) here it is: a fully dimmable white light! This of course is a very incomplete answer but so are the answers red or blue-green and you should know why. 

Let’s start with red, specifically what I will call the red light myth. 

I believe the myth started in the photographic darkroom. 

Until about 1906 most photosensitive material (plate, film, and paper) was not very sensitive to red.  Some of these orthochromatic materials are still used. This allowed these materials to be dealt with for a short time under a relative bright red light because the human eye can see red if the level is bright enough. The fact that L.E.D.s (having a number of advantages over other light sources) were economically only available in red for some time has also help to perpetuate this myth. 

As more research about the eye was done it was found that the structure responsible for very low light vision, the rods, were also not very sensitive to red. 

It was assumed then that like film you could use red light, which is seen by the red sensitive cones (there are also blue and green sensitive cones to give color vision), without affecting the rods. 

It takes a while for true night vision to be recovered.  About 10 minutes for 10%, 30-45 minutes for 80%, the rest may take hours, days, or a week. The issue is the chemical in the eye, rhodopsin - commonly called visual purple, is broken down quickly by light.  The main issue then is intensity; color is only an issue because the rods (responsible for night vision) are most sensitive at a particular color. That color is a blue-green (507nm) similar to traffic light green (which is this color for a entirely different reason). It would seem that using the lowest brightness (using this color) additional light needed for a task is the best bet to retain this dark adaptation because it allows rods to function at their best. 

Unfortunately there are a number of drawbacks using only night vision. 

Among these are:   The inability to distinguish colors.  
No detail can be seen (about the same as 20/200 vision in daylight).  
That nothing can be seen directly in front of the eyes (no rods in the center of the retina), you must learn to look about 15-20° off center.  
Only motion can be detected well, therefore you may have to learn to move your eyes to detect something that doesn't move.  
Objects that aren't moving appear to move (autokinesis).  This has probably led to a number of plane crashes.  

If you need to see directly in front of you or see detail you need red.  Like many myths the red light myth has some basis in fact.  The red truth? 

Why red?  The center 1.5% of your retina (the fovea) which provides you with most detailed vision is packed almost exclusively with red sensitive cones. 

This is the same area that has no rods and is responsible for the night blind spot.  There are fewer total green sensitive cones than red.  The number of blue sensitive cones is very small compared to green and red. 

Which is just as well since the lens in the human eye cannot focus red and blue at the same time.  And using green really only changes perceived brightness because of the way the signals are processed in our neural pathways. Unlike a digital camera, more pixels, in this case, doesn't give us more detail. 

[img]image002.gif[/img]Chart showing the distribution of rods vs cones.  Note the absence of rods in the center and the absence of both about 15° away from the the center toward the nose where the optic nerve passes. 

At first glance the tendency would be to pick the hue of red at which we are most sensitive (566nm) which would make sense except for the real reason: we don't want to involve the rods.  The reason is the rods share the neural pathways with the cones so that you have this fuzzy image overriding the detailed one.  This effect disappears at slightly higher mesopic levels which is why white is a good choice for most tasks.  Many people look at the numbers for sensitivity for rods and cones and forget that in most cases the numbers have been adjusted so that rod peek sensitive matches cone peak.  Rods are in fact sensitive well into the infrared (not too useful except to know that light you can barely sense can adversely impact your night vision).  The key then is finding a hue that we can have at a high enough intensity that we can see the detail we need without activating our rods to the point where they obscure that detail.  Most source say this should be nothing shorter than 650nm.  Experimentation shows a L.E.D. with a peek around 700nm seems to work best (perceived as a deep red).  Note that red may be fatiguing to the eyes. 

Conclusions:   No matter what your color choice it must be fully adjustable for intensity.  
If you need the fastest dark adaptation recovery and can adjust to the limitations, or everyone in your group is using night vision equipment then blue-green.  
If you must see detail (reading a star chart, or instrument settings) and can lose peripheral vision (see note 1), then a very long wavelength red at a very low level.  Red really only has an advantage at very low levels (were the night blind spot is very obvious).  
A general walking around light so that you don't trip over the tripod, knock over equipment or bump into people, then blue-green with enough red added to get rid of the night blind spot, or maybe just use white.  Blue-green at higher brightness also works very well and at a lower intensity than white.  
If you need to see color and detail then likely the best choice is the dimmest white light for the shortest amount of time.  
If you are in the military you must follow their rules; hopefully they will have a good course in unassisted night vision.  
If you are a pilot and say you only fly in the day, you should be aware of the problems of night vision and should consider a basic (ground) course in night flying.  
If you wonder why no one else has drawn these conclusions look at the dashboard of most cars.  The markings are large, the pointers are large and an orange-red (a compromise, for certain "color blind" persons) and at night it is edge lit with blue-green filtered fully intensity adjustable light.  

For Best night vision:  Be sure you are getting enough vitamin A or its precursor beta-carotene in your diet (needed for the visual purple).  
Green leafy stuff is best followed by vegetables that have an orange color.  Yes that includes carrots but spinach or dark leaf lettuce are better.  It is possible to get too much vitamin A especially as a supplement.  
Keep up your general health.  Smoking is also very bad for night vision, as are most illegal drugs and some prescription drugs.  
Keep you blood sugar level as even as possible.  No meal skipping.  Six small meals are better than three large meals.  For carbohydrates favor starches (potatoes, rice, and bread) over simple sugars (sweets, alcohol).  
Use dark neutral gray sunglasses, that pass no more that 15% in full sun, when outside during the day.  

True night blindness is rare.  Most of what people call night blindness is either a lack of vitamin A in the diet or a failure to understand the night blind spot. 

Cataracts, even minor ones, increase the effects of glare at night and the eye's lens does yellow and passes less light as we age which may contribute to what some call night blindness. 

Note:  The red filtered light at the intensity most people use is likely decreasing night vision much more than a properly dimmed white or blue-green light would! 

Note:  There are day blind spots also but are in a different position in each eye so are less of a problem. 

Note:  Blue-green (also called cyan, turquoise, teal and other names) as used here is NOT the combination of two colors but is a single particular hue.  I use the most common name for that hue. 

      

Mil-STD 1472F 5.8.2.2 (table XVI) display lighting   

   

Brightness of markings  

    

Condition of use  

Lighting Technique *  

cd/m2  

foot-lamberts  

Brightness Adjustment   

    

Indicator reading, dark adaptation necessary  

Red flood, indirect, or both, with operator choice  

0.07-0.35  

(0.02-0.1)  

Continuous throughout range   

    

Indicator reading, dark adaptation not necessary but desirable  

Red or low-color-temperature white flood, indirect, or both, with operator choice  

0.07-3.5†  

(0.02-1.0)  

Continuous throughout range   

    

Indicator reading, dark adaptation not necessary  

White flood  

3.5-70  

(1-20)  

Fixed or continuous   

    

Panel monitoring, dark adaptation necessary  

Red edge lighting, red or white flood, or both, with operator choice  

0.07-3.5  

(0.02-1.0)  

Continuous throughout range   

    

Panel monitoring, dark adaptation not necessary  

White flood  

35-70  

(10-20)  

Fixed or continuous   

    

Possible exposure to bright flashes, restricted daylight  

White flood  

35-70  

(10-20)  

Fixed   

    

Chart reading, dark adaptation necessary  

Red or white flood with operator choice  

0.35-3.50  

(0.1-1.0)  

Continuous throughout range   

    

Chart reading, dark adaptation not necessary  

White flood  

17-70  

(5-20)  

Fixed or continuous   



    

* Where detection of ground vehicles or other protected assets by image intensifier night vision devices must be minimized, blue-green light (incandescent filament through a filter which passes only wave lengths shorter than 600 nm) should be used in lieu of red light.   

    

† Possible error in original, read as: 0.07-0.35, likely occurred when converted to metric.   

 

This is intended only as an overview; no warranty of this information is expressed or implied   

 

[Update 17 Nov 2003] I find new myths are springing up.  Such as blue-green L.E.D.s are emitting two colors of light.  This is a mis-understanding of the color name and that this is the most accepted name for this one color.  Another is that blue improves night vision.  While at somewhat higher levels it, of course, is stimulating the rods.  It is not an optimum color.  Another long standing myth is that human visual perception is based on three colors when it is really based on four.  The rods are usually ignored because many people believe, wrongly, that at the brightness at which we perceive color the rods are no longer providing our brains with any information. In fact the perception of brightness is highly influenced by the rods well into the photopic (bright light) range of vision.  Fluorescent lamp manufacturers have used this knowledge for a long time.  "Cool White" lamps have an additional amount of green phosphor added to make us "see" them as being brighter!  Of course the whole subject of color vision and the variances thereof (wrongly called "color blindness") will require a number of new pages even in synopsis form. 

A point I forgot to cover is that to help preserve night vision in one eye the other may be closed or covered if you know you are about to be exposed to a brighter light, such as from a oncoming vehicle.  For normal observation both eyes should be kept open.  If it is difficult to concentrate on the desired image the eye not being used may be covered but not closed.  Closing affects focus and possibly acuity. 



[Update 14 Dec 2003] A very important point barely mentioned in the original is that human peripheral vision is almost completely rod based!  The implication then is that we cannot see color at the edges of our vision.  If you think we can, try this simple experiment.  You will need a small assortment of color cards (try sheets of construction paper) and someone to assist you.  Sit looking straight ahead while you’re assistant, about 6 to 10 feet away, slowly moves a random color card into the margin of your vision.  Now, while still looking straight ahead, what color is the card? 



This is the second most important factor that has been ignored in the design of outdoor lighting, the first being glare!  However this study (in pdf), at the U. S. Dept. of Transportation, is a subjective study of blue tinted headlamps.



[Update 23 Jan 2004] A few random notes to be better integrated into this document later.

Luminances are approximate and will vary with the individual and conditions.

Vision luminance rage 1 * 10-6 to 1 * 106 cd/M2

Rods luminance rage 1 * 10-6 to 1 * 103 cd/M2 (may still play a roll above this range)

Cones luminance rage 1 * 10-3 to 1 * 106 cd/M2

Explain "Purinke shift"

20/20 vision is the ability to resolve 1 minute of arc at 20 feet.

Discuss Ricco's Law.

Discuss afterimages. 

LITELite NVIS Compatibility  

MIL-STD-3009 was developed by the Department of Defense in February 2001 and superceded MIL-L-85762A. It specifies that NVIS White for crew cockpit and utility lighting. NVIS Green A is grand fathered into the cockpit for certain applications, but not for new applications.  

The chromacity of NVIS White makes it a full spectrum light even though is appears to have a green tint. Visible light can be split into the three primary colors, red, green and blue. The eye needs two primary colors to see 'white'. NVIS White, in simple terms is blue range through the green range. NVIS goggles filters allow a thin band of green light though the lens - so that users can see heads up displays and other required applications through the goggles. 

The level of light with respect to the chromacity is important due to this leak (filter) in the goggles. Other manufacturers claim to be the 'only authorized' lights produced since they meet a request for proposal standard. These claims are false - they have never tested FLITELite products how could they know? FLITELite meets and exceeds non-binding RFP standards, AND meets the modern, more stringent MIL-STD-3009, which is a binding requirement specified by the military. 

General Aviation pilots can benefit from this technology. This light spectrum and intensity is perfect for general night vision use as well.  

Read MIL-STD-3009 here.  

[img]image003.jpg[/img] 

[img]image004.jpg[/img] 

FLITELite minimizes the crossover zone by using a special combination of LED's and Filter material. The filter material ensures that the light greater than 600 nm is not transmitted.  

[img]image005.jpg[/img] 

  

  

Jim Wickert 

Vision #159 “Vision some will have some will not” 

Tel 920-467-0219 

Cell 920-912-1014

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riggs_la(at)yahoo.com
Guest

Posted: Tue Sep 07, 2010 8:14 am Post subject: dim able strip LED lighting

Another good point.  

     

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of John McMahon

 Sent: Tuesday, September 07, 2010 9:30 AM

 To: aeroelectric-list(at)matronics.com

 Subject: Re: Re: dim able strip LED lighting  

  

   

And remember when the red cockpit lighting made all of the fan markers and LF ranges mysteriously disappear from our charts on night flights!    

On Mon, Sep 6, 2010 at 7:25 PM, Lynn Riggs <riggs_la(at)yahoo.com (riggs_la(at)yahoo.com)> wrote:    

--> AeroElectric-List message posted by: "Lynn Riggs" <riggs_la(at)yahoo.com (riggs_la(at)yahoo.com)>  

  

I have flown with both, I am a retired Army pilot, and can tell you that the

 blue-green lighting has less of an impact on night vision than red and is

 easier to read charts with.  At lease the blue-green the Army used.

 

 Lynn    



 --

longg(at)pjm.com
Guest

Posted: Tue Sep 07, 2010 9:09 am Post subject: dim able strip LED lighting

I take Bilberry Extract which was used in WW2 and suggested for improving rod stimulation. Could be an old wives tale, but I do well with it. On trick to flying at night is to do it more often. Regardless of color (yes, some are better than others), choosing the best color will not automatically improve your night vision. People are always looking for a magic pill.  

   

One thing I notice is that when I fly more often at night, my vision becomes more readily sensitive to the light available. In other words, the third night is better than the first. It’s the same thing that happens when I go from the city to hunting in the woods. For the first few days I never see an animal and then almost magically I begin to see small changes in the landscape and critters moving about were before not seen.  

   

I believe they call the process adaptation. So, buy the best color that suits your needs, but better yet, sleep in Saturday morning and take to the stars more often.   

   

Glenn,  

New Garden, PA  

   

   

       

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of John Cox

 Sent: Tuesday, September 07, 2010 11:57 AM

 To: aeroelectric-list(at)matronics.com

 Subject: RE: Re: dim able strip LED lighting  

  

  

       

Excellent research material.  I work on Part 121 Airliners and your below post seems consistent with what is being done up in their cockpits (Flight decks).  My darkroom days are way in the past and images of the damage of red light left too long on either film or paper are still remembered as damaging.  

    

   

    

Being able to dim the intensity and use of the most pleasing hue seem important to me.  Thank You.  Hope your Marine contract serves you well.  

    

   

  

      

John Cox  

    

   

    

do not archive  

  

    

       

  

From: owner-aeroelectric-list-server(at)matronics.com on behalf of Jim Wickert

 Sent: Tue 9/7/2010 7:51 AM

 To: aeroelectric-list(at)matronics.com

 Subject: RE: Re: dim able strip LED lighting  

    

Jim Wickert here, I have been following this thread and have the following to put up for added fodder.  We have a Government Marine contract which we are working on that has a section for Night Illumination of Instrumentation and we are doing the scope research now. Below is some interesting information and food for thought.  At this time our general consensus is Soft White Flood of panels?  We have not released our findings to our customer however.  Take care sorry for the amount of text but this is only a snip of the 13 page findings.    

   

FLITELite Light Color, Intensity & Night Vision:  

Pilots have a choice of FLITELite colors - NVIS White (more information on NVIS White), Soft White that is NVIS friendly, Green, Red and Blue. The best light choice is NVIS White, followed by soft white, for a light that will protect your central night vision and provide full spectrum light. Green and Blue will protect central night vision as well, but blues and greens will disappear with this color of light - something for a pilot to consider prior to use. Red is also available, which will protect peripheral night vision, but not central vision as well as the soft white, blue and green. Red's on charts will also not be visible with red light, another consideration for the pilot to consider when making a color choice.   

The eyes are comprised of Rods and Cones. We hear people talk about Rods being for night vision, and Cones for day vision, and while they both have their special attributes, it would be better to classify them in the aviation environment at Peripheral (Rods) and Central (Cones) vision. Both rods and cones have a day and night mode, and they both react to light at different rates, and to have sensitivity to different light frequencies.  

Rods surround the periphery of the eye and are used for peripheral vision, and night vision. They do not see color, and do not detect motion. Rods only provide non-color vision at an acuity of 20/200. Rods are most susceptible to blue light. You never read, or scan your instruments with your Rods - or your peripheral vision - think about it. You are reading this article with your central vision - your cones.   

Cones are used for color, central vision, with visual acuity of 20/20. The cones have a focal width of approximately 20 to 30 degrees. Cones are most susceptible to red light.  

Cones are used when you read, day or night. During the day we read with our cones - during the night we need a light to read - obvious, but it shatters the red light myth in the aviation cockpit.  

[img]cid:image001.gif(at)01CB4E8D.6D0C9ED0[/img]  

So the question is what is the best light that will provide your eyes, and brain with the best light for reading? The answer is a dim white light. Look inside any of the new jets, and you will find that the lighting is white. Military cockpits specify NVIS White. NVIS White appears to have a green tint, but it is a full spectrum light. More on NVIS Compatibility   

FLITELite is set to a 25 degree field of view to maximize the physiology of the pilot’s eye. But to preserve night vision the intensity of the light is what matters. By using a full spectrum white light, the full spectrum light and low reflection reduces the amount of light needed. The 25 degree field is critical to keep the light out of our peripheral vision so we can look for traffic, and gauge height when we are making that perfect night landing.   

Under red light, magenta symbols disappear on charts, and during electrical failures, red markings on instruments and gauges are unreadable. Blue light will make Blue 100LL fuel disappear.   

Unaided night vision even now in the 21st century is still the subject of some controversy.  

For those just looking for an executive answer as to what supplemental lighting should be used to reduced the recovery time back to night vision (dark adapted or scotopic) here it is: a fully dimmable white light! This of course is a very incomplete answer but so are the answers red or blue-green and you should know why.  

Let’s start with red, specifically what I will call the red light myth.  

I believe the myth started in the photographic darkroom.  

Until about 1906 most photosensitive material (plate, film, and paper) was not very sensitive to red.  Some of these orthochromatic materials are still used. This allowed these materials to be dealt with for a short time under a relative bright red light because the human eye can see red if the level is bright enough. The fact that L.E.D.s (having a number of advantages over other light sources) were economically only available in red for some time has also help to perpetuate this myth.  

As more research about the eye was done it was found that the structure responsible for very low light vision, the rods, were also not very sensitive to red.  

It was assumed then that like film you could use red light, which is seen by the red sensitive cones (there are also blue and green sensitive cones to give color vision), without affecting the rods.  

It takes a while for true night vision to be recovered.  About 10 minutes for 10%, 30-45 minutes for 80%, the rest may take hours, days, or a week. The issue is the chemical in the eye, rhodopsin - commonly called visual purple, is broken down quickly by light.  The main issue then is intensity; color is only an issue because the rods (responsible for night vision) are most sensitive at a particular color. That color is a blue-green (507nm) similar to traffic light green (which is this color for a entirely different reason). It would seem that using the lowest brightness (using this color) additional light needed for a task is the best bet to retain this dark adaptation because it allows rods to function at their best.  

Unfortunately there are a number of drawbacks using only night vision.  

Among these are:     The inability to      distinguish colors.   
No detail can be seen      (about the same as 20/200 vision in daylight).   
That nothing can be seen      directly in front of the eyes (no rods in the center of the retina), you      must learn to look about 15-20° off center.   
Only motion can be      detected well, therefore you may have to learn to move your eyes to detect      something that doesn't move.   
Objects that aren't moving      appear to move (autokinesis).  This has probably led to a number of      plane crashes.    

If you need to see directly in front of you or see detail you need red.  Like many myths the red light myth has some basis in fact.  The red truth?  

Why red?  The center 1.5% of your retina (the fovea) which provides you with most detailed vision is packed almost exclusively with red sensitive cones.  

This is the same area that has no rods and is responsible for the night blind spot.  There are fewer total green sensitive cones than red.  The number of blue sensitive cones is very small compared to green and red.  

Which is just as well since the lens in the human eye cannot focus red and blue at the same time.  And using green really only changes perceived brightness because of the way the signals are processed in our neural pathways. Unlike a digital camera, more pixels, in this case, doesn't give us more detail.  

                                                    <![endif]--><![if !vml]>[img]cid:image002.gif(at)01CB4E8D.6D0C9ED0[/img]<![endif]>Chart showing the distribution of rods vs cones.  Note the absence of rods in the center and the absence of both about 15° away from the the center toward the nose where the optic nerve passes.  

At first glance the tendency would be to pick the hue of red at which we are most sensitive (566nm) which would make sense except for the real reason: we don't want to involve the rods.  The reason is the rods share the neural pathways with the cones so that you have this fuzzy image overriding the detailed one.  This effect disappears at slightly higher mesopic levels which is why white is a good choice for most tasks.  Many people look at the numbers for sensitivity for rods and cones and forget that in most cases the numbers have been adjusted so that rod peek sensitive matches cone peak.  Rods are in fact sensitive well into the infrared (not too useful except to know that light you can barely sense can adversely impact your night vision).  The key then is finding a hue that we can have at a high enough intensity that we can see the detail we need without activating our rods to the point where they obscure that detail.  Most source say this should be nothing shorter than 650nm.  Experimentation shows a L.E.D. with a peek around 700nm seems to work best (perceived as a deep red).  Note that red may be fatiguing to the eyes.  

Conclusions:     No matter what your color      choice it must be fully adjustable for intensity.   
If you need the fastest      dark adaptation recovery and can adjust to the limitations, or everyone in      your group is using night vision equipment then blue-green.   
If you must see detail      (reading a star chart, or instrument settings) and can lose peripheral vision      (see note 1),      then a very long wavelength red at a very low level.  Red really only      has an advantage at very low levels (were the night blind spot is very      obvious).   
A general walking around      light so that you don't trip over the tripod, knock over equipment or bump      into people, then blue-green with enough red added to get rid of the night      blind spot, or maybe just use white.  Blue-green at higher brightness      also works very well and at a lower intensity than white.   
If you need to see color      and detail then likely the best choice is the dimmest white light for the      shortest amount of time.   
If you are in the military      you must follow their rules; hopefully they will have a good course in      unassisted night vision.   
If you are a pilot and say      you only fly in the day, you should be aware of the problems of night      vision and should consider a basic (ground) course in night flying.   
If you wonder why no one      else has drawn these conclusions look at the dashboard of most cars.       The markings are large, the pointers are large and an orange-red (a      compromise, for certain "color blind" persons) and at night it      is edge lit with blue-green filtered fully intensity adjustable light.    

For Best night vision:    Be sure you are getting      enough vitamin A or its precursor beta-carotene in your diet (needed for      the visual purple).   
Green leafy stuff is best      followed by vegetables that have an orange color.  Yes that includes      carrots but spinach or dark leaf lettuce are better.  It is possible      to get too much vitamin A especially as a supplement.   
Keep up your general      health.  Smoking is also very bad for night vision, as are most      illegal drugs and some prescription drugs.   
Keep you blood sugar level      as even as possible.  No meal skipping.  Six small meals are      better than three large meals.  For carbohydrates favor starches      (potatoes, rice, and bread) over simple sugars (sweets, alcohol).   
Use dark neutral gray      sunglasses, that pass no more that 15% in full sun, when outside during      the day.    

True night blindness is rare.  Most of what people call night blindness is either a lack of vitamin A in the diet or a failure to understand the night blind spot.  

Cataracts, even minor ones, increase the effects of glare at night and the eye's lens does yellow and passes less light as we age which may contribute to what some call night blindness.  

Note:  The red filtered light at the intensity most people use is likely decreasing night vision much more than a properly dimmed white or blue-green light would!  

Note:  There are day blind spots also but are in a different position in each eye so are less of a problem.  

Note:  Blue-green (also called cyan, turquoise, teal and other names) as used here is NOT the combination of two colors but is a single particular hue.  I use the most common name for that hue.  

           

Mil-STD 1472F   5.8.2.2 (table XVI) display lighting             

          

Brightness of   markings         

              

Condition of use         

Lighting Technique *         

cd/m2         

foot-lamberts         

Brightness Adjustment             

              

Indicator reading, dark adaptation necessary         

Red flood, indirect, or both, with operator choice         

0.07-0.35         

(0.02-0.1)         

Continuous throughout range             

              

Indicator reading, dark adaptation not necessary but   desirable         

Red or low-color-temperature white flood, indirect, or   both, with operator choice         

0.07-3.5†         

(0.02-1.0)         

Continuous throughout range             

              

Indicator reading, dark adaptation not necessary         

White flood         

3.5-70         

(1-20)         

Fixed or continuous             

              

Panel monitoring, dark adaptation necessary         

Red edge lighting, red or white flood, or both, with   operator choice         

0.07-3.5         

(0.02-1.0)         

Continuous throughout range             

              

Panel monitoring, dark adaptation not necessary         

White flood         

35-70         

(10-20)         

Fixed or continuous             

              

Possible exposure to bright flashes, restricted daylight         

White flood         

35-70         

(10-20)         

Fixed             

              

Chart reading, dark adaptation necessary         

Red or white flood with operator choice         

0.35-3.50         

(0.1-1.0)         

Continuous throughout range             

              

Chart reading, dark adaptation not necessary         

White flood         

17-70         

(5-20)         

Fixed or continuous             



                 

* Where detection of ground vehicles or other protected   assets by image intensifier night vision devices must be minimized,   blue-green light (incandescent filament through a filter which passes only   wave lengths shorter than 600 nm) should be used in lieu of red light.             

              

† Possible error in original, read as: 0.07-0.35, likely   occurred when converted to metric.            

  

This is intended only as an overview; no warranty of this information is expressed or implied      

  

[Update 17 Nov 2003] I find new myths are springing up.  Such as blue-green L.E.D.s are emitting two colors of light.  This is a mis-understanding of the color name and that this is the most accepted name for this one color.  Another is that blue improves night vision.  While at somewhat higher levels it, of course, is stimulating the rods.  It is not an optimum color.  Another long standing myth is that human visual perception is based on three colors when it is really based on four.  The rods are usually ignored because many people believe, wrongly, that at the brightness at which we perceive color the rods are no longer providing our brains with any information. In fact the perception of brightness is highly influenced by the rods well into the photopic (bright light) range of vision.  Fluorescent lamp manufacturers have used this knowledge for a long time.  "Cool White" lamps have an additional amount of green phosphor added to make us "see" them as being brighter!  Of course the whole subject of color vision and the variances thereof (wrongly called "color blindness") will require a number of new pages even in synopsis form. 

 A point I forgot to cover is that to help preserve night vision in one eye the other may be closed or covered if you know you are about to be exposed to a brighter light, such as from a oncoming vehicle.  For normal observation both eyes should be kept open.  If it is difficult to concentrate on the desired image the eye not being used may be covered but not closed.  Closing affects focus and possibly acuity. 

 

 [Update 14 Dec 2003] A very important point barely mentioned in the original is that human peripheral vision is almost completely rod based!  The implication then is that we cannot see color at the edges of our vision.  If you think we can, try this simple experiment.  You will need a small assortment of color cards (try sheets of construction paper) and someone to assist you.  Sit looking straight ahead while you’re assistant, about 6 to 10 feet away, slowly moves a random color card into the margin of your vision.  Now, while still looking straight ahead, what color is the card? 

 

 This is the second most important factor that has been ignored in the design of outdoor lighting, the first being glare!  However this study (in pdf), at the U. S. Dept. of Transportation, is a subjective study of blue tinted headlamps.

 

 [Update 23 Jan 2004] A few random notes to be better integrated into this document later.

 Luminances are approximate and will vary with the individual and conditions.

 Vision luminance rage 1 * 10-6 to 1 * 106 cd/M2

 Rods luminance rage 1 * 10-6 to 1 * 103 cd/M2 (may still play a roll above this range)

 Cones luminance rage 1 * 10-3 to 1 * 106 cd/M2

 Explain "Purinke shift"

 20/20 vision is the ability to resolve 1 minute of arc at 20 feet.

 Discuss Ricco's Law.

 Discuss afterimages.  

LITELite NVIS Compatibility   

MIL-STD-3009 was developed by the Department of Defense in February 2001 and superceded MIL-L-85762A. It specifies that NVIS White for crew cockpit and utility lighting. NVIS Green A is grand fathered into the cockpit for certain applications, but not for new applications.   

The chromacity of NVIS White makes it a full spectrum light even though is appears to have a green tint. Visible light can be split into the three primary colors, red, green and blue. The eye needs two primary colors to see 'white'. NVIS White, in simple terms is blue range through the green range. NVIS goggles filters allow a thin band of green light though the lens - so that users can see heads up displays and other required applications through the goggles.  

The level of light with respect to the chromacity is important due to this leak (filter) in the goggles. Other manufacturers claim to be the 'only authorized' lights produced since they meet a request for proposal standard. These claims are false - they have never tested FLITELite products how could they know? FLITELite meets and exceeds non-binding RFP standards, AND meets the modern, more stringent MIL-STD-3009, which is a binding requirement specified by the military.  

General Aviation pilots can benefit from this technology. This light spectrum and intensity is perfect for general night vision use as well.   

Read MIL-STD-3009 here.   

[img]cid:image003.jpg(at)01CB4E8D.6D0C9ED0[/img]  

[img]cid:image004.jpg(at)01CB4E8D.6D0C9ED0[/img]  

FLITELite minimizes the crossover zone by using a special combination of LED's and Filter material. The filter material ensures that the light greater than 600 nm is not transmitted.   

[img]cid:image005.jpg(at)01CB4E8D.6D0C9ED0[/img]  

   

   

Jim Wickert  

Vision #159 “Vision some will have some will not”  

Tel 920-467-0219  

Cell 920-912-1014

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raymondj(at)frontiernet.n
Guest

Posted: Tue Sep 07, 2010 4:01 pm Post subject: dim able strip LED lighting

Greetings Jim,



I appreciate you sharing the info.  Would it be possible to make the 

balance of your research available?  I certainly understand in you 

choose not to, but I thought I'd ask.



Thanks again for making this info available.



do not archive



Raymond Julian

Kettle River, MN



On 09/07/2010 09:51 AM, Jim Wickert wrote:

 	  Quote: 	
		   Jim Wickert here, I have been following this thread and have the

 following to put up for added fodder.  We have a Government Marine

 contract which we are working on that has a section for Night

 Illumination of Instrumentation and we are doing the scope research now.

 Below is some interesting information and food for thought.  At this

 time our general consensus is Soft White Flood of panels?  We have not

 released our findings to our customer however.  Take care sorry for the

 amount of text but this is only a snip of the 13 page findings.



 FLITELite Light Color, Intensity & Night Vision:



 Pilots have a choice of FLITELite colors - NVIS White (more information

 on NVIS White <http://www.flitelite.com/isite/nvis.htm>), Soft White

 that is NVIS friendly, Green, Red and Blue. The best light choice is

 NVIS White, followed by soft white, for a light that will protect your

 central night vision and provide full spectrum light. Green and Blue

 will protect central night vision as well, but blues and greens will

 disappear with this color of light - something for a pilot to consider

 prior to use. Red is also available, which will protect peripheral night

 vision, but not central vision as well as the soft white, blue and

 green. Red's on charts will also not be visible with red light, another

 consideration for the pilot to consider when making a color choice.



 The eyes are comprised of Rods and Cones. We hear people talk about Rods

 being for night vision, and Cones for day vision, and while they both

 have their special attributes, it would be better to classify them in

 the aviation environment at Peripheral (Rods) and Central (Cones)

 vision. Both rods and cones have a day and night mode, and they both

 react to light at different rates, and to have sensitivity to different

 light frequencies.



 Rods surround the periphery of the eye and are used for peripheral

 vision, and night vision. They do not see color, and do not detect

 motion. Rods only provide non-color vision at an acuity of 20/200. Rods

 are most susceptible to blue light. You never read, or scan your

 instruments with your Rods - or your peripheral vision - think about it.

 You are reading this article with your central vision - your cones.



 Cones are used for color, central vision, with visual acuity of 20/20.

 The cones have a focal width of approximately 20 to 30 degrees. Cones

 are most susceptible to red light.



 Cones are used when you read, day or night. During the day we read with

 our cones - during the night we need a light to read - obvious, but it

 shatters the red light myth in the aviation cockpit.



 http://www.flitelite.com/isite/images/rcdist.gif



 So the question is what is the best light that will provide your eyes,

 and brain with the best light for reading? The answer is a dim white

 light. Look inside any of the new jets, and you will find that the

 lighting is white. Military cockpits specify NVIS White

 <http://www.flitelite.com/isite/nvis.htm>. NVIS White appears to have a

 green tint, but it is a full spectrum light. More on NVIS Compatibility

 <http://www.flitelite.com/isite/nvis.htm>



 FLITELite is set to a 25 degree field of view to maximize the physiology

 of the pilotâ€™s eye. But to preserve night vision the intensity of the

 light is what matters. By using a full spectrum white light, the full

 spectrum light and low reflection reduces the amount of light needed.

 The 25 degree field is critical to keep the light out of our peripheral

 vision so we can look for traffic, and gauge height when we are making

 that perfect night landing.



 Under red light, magenta symbols disappear on charts, and during

 electrical failures, red markings on instruments and gauges are

 unreadable. Blue light will make Blue 100LL fuel disappear.



 Unaided night vision even now in the 21st century is still the subject

 of some controversy.



 For those just looking for an executive answer as to what supplemental

 lighting should be used to reduced the recovery time back to night

 vision (dark adapted or scotopic) here it is: a fully dimmable white

 light! This of course is a very incomplete answer but so are the answers

 red or blue-green and you should know why.



 Letâ€™s start with red, specifically what I will call the red light myth.



 I believe the myth started in the photographic darkroom.



 Until about 1906 most photosensitive material (plate, film, and paper)

 was not very sensitive to red. Some of these orthochromatic materials

 are still used. This allowed these materials to be dealt with for a

 short time under a relative bright red light because the human eye can

 see red if the level is bright enough. The fact that L.E.D.s (having a

 number of advantages over other light sources) were economically only

 available in red for some time has also help to perpetuate this myth.



 As more research about the eye was done it was found that the structure

 responsible for very low light vision, the rods, were also not very

 sensitive to red.



 It was assumed then that like film you could use red light, which is

 seen by the red sensitive cones (there are also blue and green sensitive

 cones to give color vision), without affecting the rods.



 It takes a while for true night vision to be recovered. About 10 minutes

 for 10%, 30-45 minutes for 80%, the rest may take hours, days, or a

 week. The issue is the chemical in the eye, rhodopsin - commonly called

 visual purple, is broken down quickly by light. The main issue then is

 intensity; color is only an issue because the rods (responsible for

 night vision) are most sensitive at a particular color. That color is a

 blue-green (507nm) similar to traffic light green (which is this color

 for a entirely different reason). It would seem that using the lowest

 brightness (using this color) additional light needed for a task is the

 best bet to retain this dark adaptation because it allows rods to

 function at their best.



 Unfortunately there are a number of drawbacks using only night vision.



 Among these are:



     * The inability to distinguish colors.

     * No detail can be seen (about the same as 20/200 vision in daylight).

     * That nothing can be seen directly in front of the eyes (no rods in

       the center of the retina), you must learn to look about 15-20Â° off

       center.

     * Only motion can be detected well, therefore you may have to learn

       to move your eyes to detect something that doesn't move.

     * Objects that aren't moving appear to move (autokinesis). This has

       probably led to a number of plane crashes.



 If you need to see directly in front of you or see detail you need red.

 Like many myths the red light myth has some basis in fact. The red truth?



 Why red? The center 1.5% of your retina (the fovea) which provides you

 with most detailed vision is packed almost exclusively with red

 sensitive cones.



 This is the same area that has no rods and is responsible for the night

 blind spot. There are fewer total green sensitive cones than red. The

 number of blue sensitive cones is very small compared to green and red.



 Which is just as well since the lens in the human eye cannot focus red

 and blue at the same time. And using green really only changes perceived

 brightness because of the way the signals are processed in our neural

 pathways. Unlike a digital camera, more pixels, in this case, doesn't

 give us more detail.



 rod density vs. conesChart showing the distribution of rods vs cones.

 Note the absence of rods in the center and the absence of both about 15Â°

 away from the the center toward the nose where the optic nerve passes.



 At first glance the tendency would be to pick the hue of red at which we

 are most sensitive (566nm) which would make sense except for the real

 reason: we don't want to involve the rods. The reason is the rods share

 the neural pathways with the cones so that you have this fuzzy image

 overriding the detailed one. This effect disappears at slightly higher

 mesopic levels which is why white is a good choice for most tasks. Many

 people look at the numbers for sensitivity for rods and cones and forget

 that in most cases the numbers have been adjusted so that rod peek

 sensitive matches cone peak. Rods are in fact sensitive well into the

 infrared (not too useful except to know that light you can barely sense

 can adversely impact your night vision). The key then is finding a hue

 that we can have at a high enough intensity that we can see the detail

 we need without activating our rods to the point where they obscure that

 detail. Most source say this should be nothing shorter than 650nm.

 Experimentation shows a L.E.D. with a peek around 700nm seems to work

 best (perceived as a deep red). Note that red may be fatiguing to the eyes.



 Conclusions:



     * No matter what your color choice it must be fully adjustable for

       intensity.

     * If you need the fastest dark adaptation recovery and can adjust to

       the limitations, or everyone in your group is using night vision

       equipment then blue-green.

     * If you must see detail (reading a star chart, or instrument

       settings) and can lose peripheral vision^ (see note 1)

       <http://stlplaces.com/night_vision_red_myth/#note1> , then a very

       long wavelength red at a very low level. Red really only has an

       advantage at very low levels (were the night blind spot is very

       obvious).

     * A general walking around light so that you don't trip over the

       tripod, knock over equipment or bump into people, then blue-green

       with enough red added to get rid of the night blind spot, or maybe

       just use white. Blue-green at higher brightness also works very

       well and at a lower intensity than white.

     * If you need to see color and detail then likely the best choice is

       the dimmest white light for the shortest amount of time.

     * If you are in the military you must follow their rules; hopefully

       they will have a good course in unassisted night vision.

     * If you are a pilot and say you only fly in the day, you should be

       aware of the problems of night vision and should consider a basic

       (ground) course in night flying.

     * If you wonder why no one else has drawn these conclusions look at

       the dashboard of most cars. The markings are large, the pointers

       are large and an orange-red (a compromise, for certain "color

       blind" persons) and at night it is edge lit with blue-green

       filtered fully intensity adjustable light.



 For Best night vision:



     * Be sure you are getting enough vitamin A or its precursor

       beta-carotene in your diet (needed for the visual purple).

     * Green leafy stuff is best followed by vegetables that have an

       orange color. Yes that includes carrots but spinach or dark leaf

       lettuce are better. It is possible to get too much vitamin A

       especially as a supplement.

     * Keep up your general health. Smoking is also very bad for night

       vision, as are most illegal drugs and some prescription drugs.

     * Keep you blood sugar level as even as possible. No meal skipping.

       Six small meals are better than three large meals. For

       carbohydrates favor starches (potatoes, rice, and bread) over

       simple sugars (sweets, alcohol).

     * Use dark neutral gray sunglasses, that pass no more that 15% in

       full sun, when outside during the day.



 True night blindness is rare. Most of what people call night blindness

 is either a lack of vitamin A in the diet or a failure to understand the

 night blind spot.



 Cataracts, even minor ones, increase the effects of glare at night and

 the eye's lens does yellow and passes less light as we age which may

 contribute to what some call night blindness.



 Note: The red filtered light at the intensity most people use is likely

 decreasing night vision much more than a properly dimmed white or

 blue-green light would!



 Note: There are day blind spots also but are in a different position in

 each eye so are less of a problem.



 Note: Blue-green (also called cyan, turquoise, teal and other names) as

 used here is NOT the combination of two colors but is a single

 particular hue. I use the most common name for that hue.



 *Mil-STD 1472F 5.8.2.2 (table XVI) display lighting*



 	



 Brightness of markings



 	



 Condition of use



 	



 Lighting Technique *



 	



 cd/m^2



 	



 foot-lamberts



 	



 Brightness Adjustment



 Indicator reading, dark adaptation necessary



 	



 Red flood, indirect, or both, with operator choice



 	



 0.07-0.35



 	



 (0.02-0.1)



 	



 Continuous throughout range



 Indicator reading, dark adaptation not necessary but desirable



 	



 Red or low-color-temperature white flood, indirect, or both, with

 operator choice



 	



 0.07-3.5â€ 



 	



 (0.02-1.0)



 	



 Continuous throughout range



 Indicator reading, dark adaptation not necessary



 	



 White flood



 	



 3.5-70



 	



 (1-20)



 	



 Fixed or continuous



 Panel monitoring, dark adaptation necessary



 	



 Red edge lighting, red or white flood, or both, with operator choice



 	



 0.07-3.5



 	



 (0.02-1.0)



 	



 Continuous throughout range



 Panel monitoring, dark adaptation not necessary



 	



 White flood



 	



 35-70



 	



 (10-20)



 	



 Fixed or continuous



 Possible exposure to bright flashes, restricted daylight



 	



 White flood



 	



 35-70



 	



 (10-20)



 	



 Fixed



 Chart reading, dark adaptation necessary



 	



 Red or white flood with operator choice



 	



 0.35-3.50



 	



 (0.1-1.0)



 	



 Continuous throughout range



 Chart reading, dark adaptation not necessary



 	



 White flood



 	



 17-70



 	



 (5-20)



 	



 Fixed or continuous

 * Where detection of ground vehicles or other protected assets by image

 intensifier night vision devices must be minimized, blue-green light

 (incandescent filament through a filter which passes only wave lengths

 shorter than 600 nm) should be used in lieu of red light.



 â€  Possible error in original, read as: 0.07-0.35, likely occurred when

 converted to metric.



 ------------------------------------------------------------------------



 *This is intended only as an overview; no warranty of this information

 is expressed or implied*



 ------------------------------------------------------------------------



 [Update 17 Nov 2003] I find new myths are springing up. Such as

 blue-green L.E.D.s are emitting two colors of light. This is a

 mis-understanding of the color name and that this is the most accepted

 name for this one color. Another is that blue improves night vision.

 While at somewhat higher levels it, of course, is stimulating the rods.

 It is not an optimum color. Another long standing myth is that human

 visual perception is based on three colors when it is really based on

 four. The rods are usually ignored because many people believe, wrongly,

 that at the brightness at which we perceive color the rods are no longer

 providing our brains with any information. In fact the perception of

 brightness is highly influenced by the rods well into the photopic

 (bright light) range of vision. Fluorescent lamp manufacturers have used

 this knowledge for a long time. "Cool White" lamps have an additional

 amount of green phosphor added to make us "see" them as being brighter!

 Of course the whole subject of color vision and the variances thereof

 (wrongly called "color blindness") will require a number of new pages

 even in synopsis form.

 A point I forgot to cover is that to help preserve night vision in one

 eye the other may be closed or covered if you know you are about to be

 exposed to a brighter light, such as from a oncoming vehicle. For normal

 observation both eyes should be kept open. If it is difficult to

 concentrate on the desired image the eye not being used may be covered

 but not closed. Closing affects focus and possibly acuity.



 [Update 14 Dec 2003] A very important point barely mentioned in the

 original is that human peripheral vision is almost completely rod based!

 The implication then is that we cannot see color at the edges of our

 vision. If you think we can, try this simple experiment. You will need a

 small assortment of color cards (try sheets of construction paper) and

 someone to assist you. Sit looking straight ahead while youâ€™re

 assistant, about 6 to 10 feet away, slowly moves a random color card

 into the margin of your vision. Now, while still looking straight ahead,

 what color is the card?



 This is the second most important factor that has been ignored in the

 design of outdoor lighting, the first being glare! However this study

 <http://stlplaces.com/cgi/redirect.cgi?http://dmses.dot.gov/docimages/pdf66/133155_web.pdf>

 (in pdf), at the U. S. Dept. of Transportation, is a subjective study of

 blue tinted headlamps.



 [Update 23 Jan 2004] A few random notes to be better integrated into

 this document later.

 Luminances are approximate and will vary with the individual and conditions.

 Vision luminance rage 1 * 10^-6 to 1 * 10^6 cd/M^2

 Rods luminance rage 1 * 10^-6 to 1 * 10^3 cd/M^2 (may still play a roll

 above this range)

 Cones luminance rage 1 * 10^-3 to 1 * 10^6 cd/M^2

 Explain "Purinke shift"

 20/20 vision is the ability to resolve 1 minute of arc at 20 feet.

 Discuss Ricco's Law.

 Discuss afterimages.



 LITELite NVIS Compatibility



 MIL-STD-3009 was developed by the Department of Defense in February 2001

 and superceded MIL-L-85762A. It specifies that NVIS White for crew

 cockpit and utility lighting. NVIS Green A is grand fathered into the

 cockpit for certain applications, but not for new applications.



 The chromacity of NVIS White makes it a full spectrum light even though

 is appears to have a green tint. Visible light can be split into the

 three primary colors, red, green and blue. The eye needs two primary

 colors to see 'white'. NVIS White, in simple terms is blue range through

 the green range. NVIS goggles filters allow a thin band of green light

 though the lens - so that users can see heads up displays and other

 required applications through the goggles.



 The level of light with respect to the chromacity is important due to

 this leak (filter) in the goggles. Other manufacturers claim to be the

 'only authorized' lights produced since they meet a request for proposal

 standard. These claims are false - they have never tested FLITELite

 products how could they know? FLITELite meets and exceeds non-binding

 RFP standards, AND meets the modern, more stringent MIL-STD-3009, which

 is a binding requirement specified by the military.



 General Aviation pilots can benefit from this technology. This light

 spectrum and intensity is perfect for general night vision use as well.



 Read MIL-STD-3009

 <http://www.flitelite.com/isite/support/MIL_STD_3009.pdf> here.



 http://www.flitelite.com/isite/images/nvischart.jpg



 http://www.flitelite.com/isite/images/range.jpg



 FLITELite minimizes the crossover zone by using a special combination of

 LED's and Filter material. The filter material ensures that the light

 greater than 600 nm is not transmitted.



 http://www.flitelite.com/isite/images/nvissys.jpg



 Jim Wickert



 Vision #159 â€œVision some will have some will notâ€



 Tel 920-467-0219



 Cell 920-912-1014



 *From:* owner-aeroelectric-list-server(at)matronics.com

 [mailto:owner-aeroelectric-list-server(at)matronics.com] *On Behalf Of

 *Richard Girard

 *Sent:* Tuesday, September 07, 2010 8:35 AM

 *To:* aeroelectric-list(at)matronics.com

 *Subject:* Re: Re: dim able strip LED lighting



 Using the example of Boeing and Airbus for cockpit lighting in a good

 example of not examining the application before making a decision, IMHO.

 When was the last time an airline crew really needed to have good night

 vision for looking outside the cockpit? Unless you plan on flying on

 instruments from takeoff to touchdown, or very nearly, is this the wise

 choice?



 Even using the military, particularly what the helicopter cockpits use,

 is questionable since their decision may have been driven as much by

 compatibility with night vision equipment as the human eye.



 Just exactly how much improvement is blue/green over red? Does the

 difference amount to anything more that picking the fly poop from the

 pepper, or are we dealing with an unquantifiable "coolness factor"?



 Rick Girard



 On Mon, Sep 6, 2010 at 10:04 PM, RV7ASask <rv7alamb(at)sasktel.net

 <mailto:rv7alamb(at)sasktel.net>> wrote:



 

 <rv7alamb(at)sasktel.net <mailto:rv7alamb(at)sasktel.net>>



  >>This is an interesting dimmer. ï¿½Does it have the noise problems that

 Bob was writing about?



 I am just finishing installing the radios so I can't tell you about

 noise problems at this time. More to follow.



 Weighing in on the color of the light. I said earlier 'Stick with

 White.' I think both Mr Boeing and Mr Airbus have opted for white in the

 cockpit and I think they got it right.



 David





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=311626#311626



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