Lies, Damn Lies, and Color Rendition

[this_is_nascar]

Quickbeam, In my opinion this false claim is no different than LED light manufacturers claiming a "white" LED and "pure white light", only to find it's blue or violet or puke green.

 

[W4DIZ]

Thanks Quickbeam. I will be sticking with white leds
for every day use.
David

 

[Sigman]

I personally prefer a green led for nightvision, and red for stargazing due to the contrast of the stars on the maps.

This is why I absolutely love my two EternaLight Ergo 3s. One has the Green & White LEDs, the other has the Red & White LEDs. The best of both worlds. If I had to pick one, it would be the Green/White one!

Not to mention the HUNDREDS hours of runtime on a set of batteries!!! I own various lights with filters, but if I had to take one and only one light with me it would be the GW!

 

[Lux Luthor]

I'm not sure if your comment about sticking with white LEDs for everything was directed at only map reading or not. If it was a general statement, I disagree.

The colors can be useful, and not just for night vision. I agree you should have a white light with you in case you need accurate color rendition, which is often but not always the case. For this reason, I always have at least one type of white light.

If I had only one light, I would choose a white one, but since I have more than one, I include some colors also - particularly amber and green.

 

[papasan]

some maps, like military topo maps and night gazing maps, are made to be read with colored light in an attempt to conserve night vision. maps you find in wal-mart are probably not.

 

[RAH]

Your point about white being by far the best for color accuracy and normal map reading is very well taken. However, for star gazing, I think a red Infinity is just about perfect. It's nice and dim (yes, dim can be a good thing!) and great for reading star charts, which are designed to be read with a red light, as Papasan pointed out.

 

[EMPOWERTORCH]

White light isn't always good!
The change of streetlights from low pressure sodium to high pressure sodium or HID has led to problems of excessive glare on wet roads at night. Driving in these conditions is more hazardous than without streetlights at all, as generally you are behind the light sources on your vehicle. Road markings dissappear under a sea of white glare and light direct from the lamps themselves dilates your pupils. I find the pink light quite irritating in rain as well.
Yellow light from sodium lights doesn't scatter like white or pink light, and allows car and motorbike headlights to work better picking out signposts and road markings.
We are encouraged to dip, not dazzle oncoming drivers, but these horrendously glaring street lights are just as bad!
White light is best used in homes and in places where asccurate colour rendition is important and is most effective as an area light. Our "daylight" sensors work in full colur, whilst our night vision sensors work in monochrome. So, for extreme darkness usage cyan works the best for me!

 

[Wingerr]

Only thing about the low pressure sodium street lights is the way the yellow traffic signals disappear in the sea of yellow lights; it tends to obscure them until the light turns red- other than that, the visibility from them is better.
What puzzles me in my area is the invariable placement of those super bright lights (probably the ones you're referring to) at night time work construction sites such that they're pointing AT oncoming traffic, with no regard at all to their effects. During rainy conditions, the glare off the windshield makes driving an act of faith.

 

[Quickbeam]

How many times have you heard that "Oh, [this colored or that colored LED] is good for map reading". Well, next time you hear that, point them to this page... Take a peak and see what you think.

http://thelightsite.cruxial.com/reviews/color_rendition.htm

 

[B@rt]

For usefullness, you are absolutely right, but oh, to have a 5W royal blue.... :drewl:

 

[INRETECH]

That was a very good comparison and review, too often people look at just the brightness numbers and use that to purchase their item(s)

Just like people look how much power a stereo puts out, without looking at the THD numbers

Sure - its bright - and fun to impress their friends

But, us humans have been using SOL for several million years to see with; and any other color is going to affect how we percieve things

We have a Helios with 2x5w Blues and 1x5w Green, and yes - it is *VERY* bright and you can see it for a long ways away - but, it messes up colors

Mike
www.inretech.com

 

[Minjin]

I'll stick to my personal belief that the perfect tactical light is green. Best wavelength to blind someone with. And I don't think color rendition is necessary in room clearing.

Read the Cyan Inretech thread...

Mark

 

[camisdad]

nice job quickbeam - nothing like data to take care of many theories... Thanks!

 

[Icebreak]

Quickbeam-

As a kid I was taught that color is the reflection of that color from the spectrum. I thought that a blue light would make blue things show up more but you have proven this to in diametric opposition to the facts. I've been shining my Tektight 7 blue LED at everything and except for florescents you are right!

Bart -

What you said.

 

[Quickbeam]

Some good responses! The comparison is there to dismiss the claim that colored LEDs are better all-around lights and are usable in the same manner as white LEDs. I've seen this claim many times on various sites and it's just a bunch of BS. I simply set out to prove it's BS through direct comparisons.

However, the comparison is not about brightness, just color rendition. I use my very dim white infinity all the time and love it. I have a pilot friend who uses a red infinity and loves that one in the cockpit. Sometimes dimmer is better, and sometimes a colored light is more comfortable or better to use under VERY specific situations. However, in general, and in most circumstances, a white light is better to use than a monocromatic one because you can see the full range of colors, the contrasts between the colors, and therefore more detail.

 

[tiktok 22]

Hi Guys,

Quickbeam, you are EXACTLY correct. I am a pressman for a high quality printer. Without getting technical, when printing maps (or any other 4-color document) colors lay over other colors. This is called trapping. It is very difficult to see with the naked eye, but with colored filters or different colored LED's we can pick out a specific colors to see how it is printing or trapping. This has been used in printing for many years. Just my 2cents.

 

[EMPOWERTORCH]

Wingerr, You're perfectly correct... it happens here in England too and makes for difficult motorcycling in rainy conditions!....was that a pushbike I crashed into....sic...
The dazzle from badly adjusted and poorly designed car headlights is yet another thing that makes for leap of faith motorcycling - one of the reasons why my Super Dream is fitted with an additional spotlight...I've moved way of the original topic so I shall get back to the original question...coloured LED lighting in torches.
I'm a keen nightwalker and for years like many others have used filament bulb torches to light my way...until I discoveered the benefits of LED lighting and converted an old 4C torch to LED with a Nichia 8000mcd Green LED, and was astounded by how much light the LED was producing from my Dec-90 expiry c cells. The torch was being powered by some batteries I stumbled across in the basement. I thought that there would be no power from hem, but the LEd lit up spo well that I took he torch out for its maiden voyage around the public footpaths around our village.
I was hooked! The green light was really effective particularly in and amongst trees and vegetation. For a while it was my EDC until I built somthing more pocketable in the form of my first BT1. This used the same Nichia LED in a much smaller case and was powered by 4 AAA's!
Green LED's give impressive results in most outdoor situations. I p=roceeded to construct more and more torches... initially for my own pleasure until people started to buy them... and I realized that I had a viable small business opportunity here. Thus was born EMPOWERTORCH.
In the end, strictly speaking no colour is any better than another colour... it s about what the torch user wants and what he feels happy with. For night walking I would always use a cyan or green torch; for reading I have an orange 8000mcd LED torch with a NiteIse headband so the torch can be used hands free.
For colour rendition, a portable fluorescent tube emits a great array of frequencies of light White LED's may look white but only emit a small number of frequencies as reported on his web site a few weeks ago!

 

[ikendu]

Hmmm...here is just one bit of practical experience.

I have two Infinities:
Yellow and Blue/Green

The Yellow one is just about too dim to be useful at all whereas the Blue/Green is quite useful and still delivers really long battery life (the white...which I don't have, I have seen in posts as "just too dim").

So...what does it mean?

(I am remembering a line from "Big Trouble in Little China": "two girls with green eyes... what does it mean????")

BTW...I finally started carrying a White Photon III 'cause the white color is just too useful for accurate color rendition to be ignored. It displaced my turquoise ARC AAA (which displaced my red Photon II). So...bottom line, I'm carryin' white!

 

[Blikbok]

I find white light very handy in my job, but I have a blue-green Infinity I am never without. I use it all the time for navigating in the dark and while stargazing. (I have a starchart on my PDA, and the backlight is "indiglow" blue-green).

I agree with the point of the article however-- I have only two colored lights, the rest are blindingly white.

So, yes, for mapreading, and any sort of color vision, we need white light. But there are reasons for the less intense colored LED's. Mapreading isn't the only purpose.

 

[brightnorm]

Is there any consensus on the preferable (notice I didn't say "best") color for night walking in a rural environment? (asphalt or dirt roads, fields and trees)

I've always assumed my "white" leds were best and never tried any others. Perhaps I'm missing out?

Brightnorm