Incan versus LED...

2xTrinity

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So what do you think of the color of this web site back ground?
I used to administer an internet forum several years ago. The viewers complained about the overly bright background, so I started a poll -- light or dark background, with fairly strong opinions on both sides and a relatively even split vote. I ended up "splitting the difference" and going with a gray background.
re-calibrate your monitor to a different white point. From the factory, most monitors are set to a very high white point, like 9300K or something like that, but there are user adjustable options here:
9300k is a throwback to older CRTs. Every LCD I've ever used, ann even newer CRTs all default to 6500k. I wouldn't recommend deviating from the D65 standard that as that's what digital photographers and web designers expect users to be running.
I see an increasing number of (likely) aftermarket auto HID headlights that have various shades of blue that have an irritating, more blinding effect on my vision than normal sealed beam incan headlights. In addition, if I use fluorescent 4 foot long tube (overhead in offices) bulbs, I almost MUST combine a "Cool White (4100°K" that appears bluish alone) with a wide spectrum (i.e. Sylvania Gro-Lux brand listed as 3400°K or 3500°K) that appears pinkish alone. I have spent my own money replacing bulbs in several work environments (with consent of owner) in the past. Using this handy °K color lighting guide which displays example photos of different environments, I can now see that the 3500°K is too red, but 4100°K is too blue even in these photos. If I don't get a proper light in my environment, I accumulate an increasing level of stress (minor, but quantifiable) over time. This last link finally explains what I could never quite specify until now. I now see that they don't make the correct bulb to fit my preferences, which would be about 3750°K. I had never taken the time to understand all of this until now.
This is interesting, but I believe this has more to do more with light sources that are tinted, or slightly off compared to blackbody, than it does with the color temperature. For example, my neutral LEDs are all around 4000k, but when viewed side-by-side with cool white fluorescents, the fluorescent appear blue-green, and the LED appears red. 3500k tubes on the other hand tend to have a reddish tint. This is very obvious if you run a hotwire at 3500k near a fluorecent, the hotwire will appear yellow and the fluorescent will look red. Combine the blue-green hue of the 4100k tube with the red hue of the 3500k tube, and you should end up with a correct white balance. It should be perfectly possible to make a tube with a phosphor that is an equal blend of the 4100k phosphor, and a 3500k phosphor, and have a perfectly white-balanced 3750k tube.
 

LuxLuthor

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Web page or other object colors have little to do with this discussion. I'm talking about lighting transmission wavelengths having a long term effect on human physiology, and eye sensitivity perception vis-a-vis S/M/L cone distribution.

This website has a white background with various shades of blue that are no problems to visualize. Having a proper computer display is a whole other can of worms, and is related to many factors.

Again, the issues in this topic are not about being able to look at colors in a photo/webpage/object, etc. My issues regarding LED's are due to their very narrow (usually only 30 nm) band at a specific nanometer wavelength that is not realistic or ideal in most outdoor circumstances.
Eyes have rods, and 3 different types of cones that are used to properly render colors, hues, and contrasts. Humans can see 10 million colors in the light wavelength range of 380 to 760 nm.

Having a narrow 30nm LED wavelength spike is an ineffective light source for the human eye as compared to broad spectrum incandescent, even if both have an identical so called "dominant wavelength" color (i.e. the same 3500°K).

The broad spectrum nature of sunlight and incan light sources are given the highest "100" score on the CRI (Color Rendering Index), even if its "dominant (color temperature) wavelength" is not ideal to a particular circumstance.

These sources (sun/incan) will use the three types of cones more completely which is an important part of seeing accurate colors and contrasts. LED's cannot achieve this with their narrow band of lighting. LED's do not utilize the complex biological evolutions of the human eye.
 

LuxLuthor

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I have it on good authority that the men who use LED's have mothers who wear Army pants.
 

cat

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LuxLuthor, I think the high frequency flickering of fluorescents is also a factor (particularly when combined with the high frequency flickering / refresh rate of computer monitors), with some people more sensitive to it than others.

Here where I sit at work, there are two 3x36W fluorescents above me. (And a fitting with 3 shorter tubes about 2 meters in front of me.) Only one of the six tubes is working; the others, I've insisted that they don't replace them. I don't need them, I work on computers and the one tube and the rest of the ambient light around is enough for reading and writing on paper anyway.
 

jtr1962

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LuxLuthor, I think the high frequency flickering of fluorescents is also a factor (particularly when combined with the high frequency flickering / refresh rate of computer monitors), with some people more sensitive to it than others.
Fluorescents don't flicker any more. That used to happen when they still used magnetic ballasts. If your work place is using those then they should replace them ASAP. The power saved by using T8s instead of T12s will more than pay for the new fixtures/lamps.
 

jtr1962

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Having a narrow 30nm LED wavelength spike is an ineffective light source for the human eye as compared to broad spectrum incandescent, even if both have an identical so called "dominant wavelength" color (i.e. the same 3500°K).
Monochrome LEDs have a fairly narrow bandwidth, not whites. Every white LED spectrum I've looked at is pretty broad. The main things lacking are reds past about 600 nm and a small dip in the 500 nm area. This problem could easily be corrected in the future with better phosphors.
 

LuxLuthor

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Fluorescents don't flicker any more. That used to happen when they still used magnetic ballasts. If your work place is using those then they should replace them ASAP. The power saved by using T8s instead of T12s will more than pay for the new fixtures/lamps.

Agreed. My color balance issues were never about flickering fluorescents or interactions with CRT's that need to have a proper refresh rate, background ambiance lighting, limited exposure times, adequate eye blink rates, etc. My previously mentioned color light issues were not related to computer use at all.

I don't care about efficiency, so I don't care about replacing T12's with T8's anymore than I care about the irrelevant (to me) promotion of L/W LED efficiency (assuming the numbers were properly obtained with an adequately calibrated for LED output light meter). What I care about is having the right light for the right job. It's why I bought about 1,500 incan bulbs after seeing the enviro-terrorists get the mercury filled CFL replacing incan law passed.

Monochrome LEDs have a fairly narrow bandwidth, not whites. Every white LED spectrum I've looked at is pretty broad. The main things lacking are reds past about 600 nm and a small dip in the 500 nm area. This problem could easily be corrected in the future with better phosphors.

I have always agreed that LED's are making progress, and the white LED's (i.e. a narrow band blue monochromatic LED with a yellow phosphor coating) are better despite their Stokes shift issues and missing spectrum elements you listed.

For my purposes, these so called "white LED's" are still not "soup yet" from what I have seen or read about. I believe the best hope lies with multi-emitter combinations, but then you start losing those pesky heat and power source attributes which LED Jockeys adore.

Eventually LED's will be closer to the CRI 100 of incan/sunlight which is why it keeps getting harder to defend incan superiority for outdoor uses. However, for the 39th time, the proper human eye light spectrum is just one of the many factors I list about incan vs. LED...so let's not get too sidetracked here. :candle:
 
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saabluster

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Do you guys know if this aspheric display of a Fenix P2D using Rebel is an intentional partial phosphorous coating to achieve a better color? I posted pix in this thread on aspherics.

I accidentally posted a response in the other forum. Short answer is no. Enough blue escapes from the phosphor layer as is. There is no reason to allow more through.
 

bridgman

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OK, 14 years later and it's getting closer to an apples-to-apples competition.

LEDs are winning on runtime for the same brightness across the board, but there are still big ongoing debates about LED colour temperature and what best competes with an incandescent for colour rendition.

Pictures suggest that a natural white LED is far ahead of incandescent in terms of colour rendition, but when you hold the flashlights in your hand it seems that LEDs aren't really there yet. I have trouble with that because it seems that enough years have passed for LED vendors to get the phosphor mix right and stomp incandescents into the dirt, but it doesn't seem to have actually happened yet.

The flipside though is that most vendors have gone over to the dark (LED) side and are not really competing on the incandescent front any more. I hope it's not just Lumens Factory competing on the incandescent side, but even if it is they are doing a fantastic job and deserve our support. I just ordered a couple of Seraph hosts and a half dozen bulbs.

I guess it's all going to boil down to a question of what is the most perfect colour temperature. The highest CRI seems to be associated with bulbs in the incandescent range of colour temperatures, but the latest LEDs seem to be giving better colour rendition from LEDs in the 4000K range, which seem to be the exclusive domain of LEDs.
 
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