Post by thread:[EE] Safe viewing colors?

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'[EE] Safe viewing colors?'
2005\04\21@233020 by Jinx

Tagged [EE] > Anyone have a link or doc that indicates which colors of (LED) light > are generally better for displays -- easier on the eyes, quicker to read, > etc? I'm trying to find some facts on this, rather than just "generally > known" info I Googled for eye "spectral response" and got a lot of hits. This one has a response curve http://www.centronic.co.uk/products_electro_products_eyeresponse.asp Seems to indicate ~ 550nm, which is green, which is where previous threads like this have concluded (eg night vision goggles / light intensifiers are green)

2005\04\22@003359 by PicDude

Hey Jinx, I've heard much conflicting information on what we're most responsive to -- both red and green have been popular. But other than response, I'm willing to bet that the least destructive color (to our eyes) will be different. Pilots use red light since it has less persistence, but that does not necessarily imply that it's the safest for long-term viewing. Interesting search terms your used, but oddly when I type those in now, I do not get that specific hit that you got. Hmmm. Cheers, -Neil. On Thursday 21 April 2005 10:29 pm, Jinx scribbled: {Quote hidden}> Tagged [EE] > > > Anyone have a link or doc that indicates which colors of (LED) light > > are generally better for displays -- easier on the eyes, quicker to read, > > etc? I'm trying to find some facts on this, rather than just "generally > > known" info > > I Googled for eye "spectral response" and got a lot of hits. This one > has a response curve > > http://www.centronic.co.uk/products_electro_products_eyeresponse.asp > > Seems to indicate ~ 550nm, which is green, which is where previous > threads like this have concluded (eg night vision goggles / light > intensifiers > are green)

2005\04\22@012931 by Hopkins

Have you seen this link? http://www.theledlight.com/technical3.html _______________________________________ Roy Tauranga New Zealand _______________________________________ -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.10.2 - Release Date: 21/04/2005

2005\04\22@030100 by Jinx

> to bet that the least destructive color (to our eyes) will be different. Is there *any* colour that is destructive ? I'd have thought that the colour the eye is most responsive to can be used at a lower intensity. As I mentioned, night-vision goggles are green and used extensively and for long periods (search and rescue, military). You might look around for health studies in those areas

2005\04\22@043522 by Alan B. Pearce

>I'd have thought that the colour the eye is most responsive to can >be used at a lower intensity. As I mentioned, night-vision goggles >are green and used extensively and for long periods (search and >rescue, military). You might look around for health studies in those >areas I always thought that glow green more because that is an available phosphor for the image intensifiers that has a short persistence time. Most yellow phosphors (which is the colour I always understood our eyes are most sensitive to) have very long persistence times (witness the long afterglow on old analogue scopes with yellow screens).

2005\04\22@050510 by Russell McMahon

Human eye is most responsive to a yellowish-green colour. Doesn't mean it's the most pleasant to view though. Some emergency appliances are this colour. RM

2005\04\22@054825 by Jinx

Neil, do you have any reason to believe that any particular colour is actually harmful or detrimental ? (apart from strong UV/IR/atomic blasts, magnesium flashes etc which are harmful for reasons other than colour) For example - o aborigines or desert people who see a lot of yellows and blues o forest people who see a lot of greens and browns o butchers who see a lot of red ? (just kidding - specious)

2005\04\22@083347 by Mike Hord

> Neil, do you have any reason to believe that any particular colour > is actually harmful or detrimental ? (apart from strong UV/IR/atomic > blasts, magnesium flashes etc which are harmful for reasons other > than colour) Logically, I'd expect colors of light which our eyes are less responsive to would be "damaging" in the sense that if we need to spend a lot of time extrapolating data in that color, they would cause eyestrain which over time MAY be detrimental to our eye health. I don't know about that, however. If nothing else, you'll cause your users a load of trouble. Again, let me make my plea: PLEASE don't use a yellow/green LED as a status indicator. People like me can't see the difference! Avoid things like that. If you can, use a combination like blue/red- I think that by avoiding red/green, yellow/green, or blue/yellow as combinations for status indication, you'll make the lives of 99.9% of the color-blind public much better. Mike H.

2005\04\22@090825 by Jinx

> Again, let me make my plea: PLEASE don't use a yellow/green > LED as a status indicator. People like me can't see the difference! > Avoid things like that. If you can, use a combination like blue/red I hadn't thought of the inconvenience factor - only ever used the common R/G. Now that you've suggested alternatives I may look into it for future products (would look cooler than R/G too) http://www.lsdiodes.com/multi-color/ The B/W & R/W reminded me of another example of people exposed to a lot of one colour - white (Eskimos), although UV reflection probably causes problems, as in those who look at bodies of water a lot Straying from the point http://it.stlawu.edu/~jahncke/clj/polarbearpics/PolarBears.html

2005\04\22@121405 by Peter

On Fri, 22 Apr 2005, Jinx wrote: > Tagged [EE] > >> Anyone have a link or doc that indicates which colors of (LED) light >> are generally better for displays -- easier on the eyes, quicker to read, >> etc? I'm trying to find some facts on this, rather than just "generally >> known" info > > I Googled for eye "spectral response" and got a lot of hits. This one > has a response curve > > http://www.centronic.co.uk/products_electro_products_eyeresponse.asp > > Seems to indicate ~ 550nm, which is green, which is where previous > threads like this have concluded (eg night vision goggles / light > intensifiers > are green) Except anything but red ruins night vision and low intensity dark blue seems to be the best for 'nightlight' type of appliactions. Peter

2005\04\22@124706 by olin_piclist

Peter wrote: > low intensity dark blue Phew! I wouldn't have to come up with high intensity dark blue. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

2005\04\22@130706 by Peter

On Sat, 23 Apr 2005, Jinx wrote: > I hadn't thought of the inconvenience factor - only ever used the > common R/G. Now that you've suggested alternatives I may look > into it for future products (would look cooler than R/G too) Found on a forum suggested by you (in another context <g>) http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Number=203850&page=0&view=collapsed&sb=5&o=all&fpart=1 Peter

2005\04\22@163911 by Russell McMahon

> I hadn't thought of the inconvenience factor - only ever used the > common R/G. Now that you've suggested alternatives I may look > into it for future products (would look cooler than R/G too) Red-Green colour blindness is by far the most prevalent form amongst men - about 10%. Far lower in women. Interesting visual RG color-blindness test http://www.toledo-bend.com/colorblind/Ishihara.html RM

2005\04\22@172433 by Dave King

Are you sure about the color blindness number? I thought it was a bit lower than 10% for the male population, somewhere about 5%. Good info though. Dave -> {Original Message removed}

2005\04\22@221349 by Russell McMahon

> Are you sure about the color blindness number? I thought it was > a bit lower than 10% for the male population, somewhere about 5%. Stats vary by site. That came from a site that was dealing in statistics of various sort and gave both a population stat and a current incidence stat SO the 10% figure should hopefully be reasonably OK. RM

2005\04\23@145220 by Peter

On Fri, 22 Apr 2005, Olin Lathrop wrote: > Peter wrote: >> low intensity dark blue > > Phew! I wouldn't have to come up with high intensity dark blue. ? Anyway 'night illumination' in places like hospitals and railroad sleeping cars is dark blue. Apparently it does not disturb sleep or something like that. It works for me at least. I think that it has to do with the red tint imparted to light by closed eyelids. The blue does not go through those 'filters' so the room appears to be darker than it really is when lit blue and seen through closed eyelids. But I may be wrong. Peter

2005\04\23@153740 by Peter

On Fri, 22 Apr 2005, Olin Lathrop wrote: > Peter wrote: >> low intensity dark blue > > Phew! I wouldn't have to come up with high intensity dark blue. Hmm, dark blue refers to quite far into the edge of UV, i.e. 450nm-ish and lower. Now I understand the joke in your posting. Peter

2005\04\24@014449 by Tony Smith

> > Peter wrote: > >> low intensity dark blue > > > > Phew! I wouldn't have to come up with high intensity dark blue. > > ? Anyway 'night illumination' in places like hospitals and railroad > sleeping cars is dark blue. Apparently it does not disturb sleep or > something like that. It works for me at least. I think that it has to do > with the red tint imparted to light by closed eyelids. The blue does not > go through those 'filters' so the room appears to be darker than it > really is when lit blue and seen through closed eyelids. But I may be > wrong. The movie industy has been putting blue filters on cameras to simulate night for some time. Funny how there always seems to be a full moon in all those old movies... Another reason for blue lights found in other areas (toilets, garages etc) is that it makes it hard to find veins in your arms. This makes injecting heroin (or your preferred illegal narcotic) a bit difficult. However, you can use a marker (the one you use for breaking the copy protection on your CDs) to mark out the veins beforehand. High tech solution, meet age-old cunning. Tony

2005\04\24@042202 by Nigel Duckworth

-------Original Message------- From: Tony Smith <snip> High tech solution, meet age-old cunning. TOO MUCH information! I'm sure most of the people you were describing have worked out this dodge for themselves but why risk enlightening the odd one that hasn't by broadcasting it? Nigel Duckworth

2005\04\24@093545 by olin_piclist

Peter wrote: >>> low intensity dark blue >> >> Phew! I wouldn't have to come up with high intensity dark blue. > > ? The point was that specifying "low intensity" together with "dark" doesn't make much sense, since it gives the the impression that you could have a high intensity dark light or a low intensity light one. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

2005\04\24@094518 by olin_piclist

Peter wrote: > Hmm, dark blue refers to quite far into the edge of UV, i.e. 450nm-ish > and lower. Now I understand the joke in your posting. I've always understood "dark" or "light" to refer to intensity. The "blue" part refers to the hue. Ordinary English is a bit ambiguous about describing color saturation. "Washed out" or "grayish" definitely refer to low saturation, but there doesn't seem to be a universal term for high saturation. If the color happens to be red, then you can say "fire engine red". "Brilliant" can mean high saturation, but also high intensity depending on context. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

2005\04\24@105641 by Dave Lag

Deep? Olin Lathrop wrote: > I've always understood "dark" or "light" to refer to intensity. The "blue" > part refers to the hue. Ordinary English is a bit ambiguous about > describing color saturation. "Washed out" or "grayish" definitely refer to > low saturation, but there doesn't seem to be a universal term for high > saturation. If the color happens to be red, then you can say "fire engine > red". "Brilliant" can mean high saturation, but also high intensity > depending on context.

2005\04\24@221537 by Russell McMahon

Cutting and pasting but preserving context: >>>> low intensity dark blue >>> Phew! I wouldn't have to come up with high intensity dark blue. >> Hmm, dark blue refers to quite far into the edge of UV, i.e. >> 450nm-ish and lower. Now I understand the joke in your posting. > I've always understood "dark" or "light" to refer to intensity. The > "blue" part refers to the hue. Your understanding is understood. As a joke the comment is somewhat obscure and therefore somewhat excellent :-). But, using the term "dark" and "light" to differentiate colours of differing but similar wavelength or mix of wavelengths is also extremely common and time honoured. Googling: "dark blue" "light blue" - 694,000 eg "... Dark blue is associated with Oxford University and light blue with Cambridge University." ____________ "dark green" "light green" - 282,000 _________ You'll find in the vast majority of references that degree of saturation / brightness is not the point of differentiation. FWIW Many colours can not be produced from a single wavelength but are a mix of pure wavelengths which our eye-brain systems assign a "colour". The relative brightness of the 2 or more combined pure wavelengths are varied to form various "colours", but for a fixed ratio of intensities the "darkness" or "lightness" of the resultant colour is not dependant on the combined absolute intensity. See eg http://others.servebeer.com/temp/ColourChart.jpg CIE Chromaticity diagram circa 1931! (Taken from Luxeon LED "all in one" app note.) Note that using any 3 Luxeon LEDS does not allow a good rendition of the whole of the colour space. The triangle formed on the CIE diagram using RGB LEDs leaves out much of greeny-blue area. Using any 3 other single wavelength colours also leaves out substantial area. By adding CYAN to the usual RGB mix you get an irregular quadrillateral which includes much more of the CIE colour space & so (obviously) greatly increases available colour range. Using as "dark" a blue as possible improves the range of possible colours produced. If only 3 LEDs are to be used to produce as wide as possible a range of colours then a 518 nanometer emitter plus as "dark" a red and as "dark" a blue as possible would be ideal. This is not available from Luxeon - the nearest are cyan at 505 nm and green at 530 nm. The perceived colour difference between these is large. RM . --------------------------------------------------------------------------------

2005\04\25@073441 by Gerhard Fiedler

Olin Lathrop wrote: > I've always understood "dark" or "light" to refer to intensity. The "blue" > part refers to the hue. Ordinary English is a bit ambiguous about > describing color saturation. "Washed out" or "grayish" definitely refer to > low saturation, but there doesn't seem to be a universal term for high > saturation. If the color happens to be red, then you can say "fire engine > red". "Brilliant" can mean high saturation, but also high intensity > depending on context. Wouldn't "clean" usually imply high saturation when applied to color? Gerhard

2005\04\25@081834 by olin_piclist

Gerhard Fiedler wrote: > Wouldn't "clean" usually imply high saturation when applied to color? Hmm, I suppose it could in some contexts. I was looking thru some references and found "vivid" and "bold" as the best words so far for describing highly saturated colors. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

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