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Everyone knows the feeling when you perfect a photo edit on your computer, only to find out the colors are way off when you view the photo on a different device, or someone else's monitor or display.

Most desktop and laptop screens have a very bright "blue light" mode set as default, which is now considered a health hazard for the eyes. Some computer have a setting to switch "blue light" off, causing the monitor to instead appear alot warmer and more yellowish than when blue light mode is on.

How then does this affect our perception of the true (100%) Adobe RGB and sRGB color gamut ranges when editing photos? Computer screens are typically only 45% - 65% accurate for the Adobe RGB and sRGB spectrums, and to make matters worse, there's this blue tinge from "blue light", or the yellow tinge from "blue light off". Are we deceiving our eyes more when using blue light mode, or the non-blue light mode that is more yellowish?

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  • \$\begingroup\$ "... which is now considered a health hazard for the eyes." Not really, it's considered a detriment to going to sleep when one has been using a blue screen in the two hours or so before bedtime. "Computer screens are typically only 45% - 65% accurate for the Adobe RGB and sRGB spectrums." Adobe RGB and sRGB aren't spectrums, they're color gamuts. Spectral colors are at the edge of the curve around the limits of CIE color space, and very few monitors can actually reproduce very many of them, even 100% AdobeRGB compliant monitors. \$\endgroup\$
    – Michael C
    Mar 15, 2023 at 11:59
  • \$\begingroup\$ The best crash course for understanding color spaces I've seen. \$\endgroup\$
    – Michael C
    Mar 15, 2023 at 12:30

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My first thought would be: The "Blue Light is a dangerous to the eye" is really misunderstood.

Modern monitors do not emit dangerous radiation. You could say so during the cathodic rays monitor era, but there was no blindness epidemic even then.

What is recommended is to warmer the hue of our cellphone devices before going to sleep (or not viewing it at all), so our brains follow a more natural path of seeing warm light, like a sunset as preparation to sleep. And that is because of our addiction to watching our phones all the time can alter sleep cycles.


Regarding the specific question, that is why standards are for, and our responsibility is to do our best with our available resources. And the standards are our friends. But we can not hope everybody has their devices "calibrated". It is enough to turn on the auto-brightness in a cellphone to have values all over the place just walking into a room.

Regarding temperature, the recommended standard is to use 6500°K, or D65.

And the second most important element is our gamma setting. If you do not have a device like Datacolor Spyder or Photo1 you can use a simple table and your graphics card software to adjust the gamma to 2.2. Here is a really old tutorial I made with the test patterns. You have to use a browser that does not change the zoom level by default, so you can use Firefox.


I must say that I do not recommend using the D50 standard, even for "printed material" for "normal people. There are color-matching boxes using D65 If you want to get one, and you have only one workflow.

The D50 illuminant is for commercial print. Although there are some cases for Inkjet printing, it is mostly targeted to Offset, flexo, etc.

If you want to send your photos to be professionally printed, a) ask them, b) send only some test photos, some with D65, some with D50, c) compare them, and d) decide.

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  • \$\begingroup\$ Please cite the current ISO Standard that specifies D65? The last time I looked, it was still D50 for print matching. Current practice among many imaging professionals may be D65, but I do not believe the ISO Standard has changed. \$\endgroup\$
    – Michael C
    Mar 11, 2023 at 2:46
  • \$\begingroup\$ I edited a bit my comment. I did not say that it changed. I say that for normal people I do not recommend using it unless you are working in a workflow that actually uses it. :) \$\endgroup\$
    – Rafael
    Mar 11, 2023 at 3:18
  • \$\begingroup\$ You're still using the word standard when the ISO Standard remains D50 for still photography. You can recommend whatever you wish, but it's not an official standard for still images. The official standard for movie projection is not D65, either. It's specified in DCI-P3 and is 6300K with a slightly green bias, so more "D63", if there were such a thing, than D65. \$\endgroup\$
    – Michael C
    Mar 12, 2023 at 6:14
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It depends somewhat upon whether your target for the monitor is D65, which has become pretty much universal among graphic design professionals, or D50, which has long been the standard for print matching.

Graphic design pros use D65 because it matches the very blue default settings of most portable devices such as smart phones and tablets. Movie projectors in theaters and most televisions also target close to D65. Manufacturers set TVs and portable devices at around D65 because when compared to other devices set to warmer color temperatures in side-by-side tests, consumers say they like the look of the bluer screens.

enter image description here

As anyone can see in the graphic above, D50/D55 are much closer to the actual white point of CIE color space than D65 is.

Photographers who do a lot of print work tend to set their screens at D50, which is 5000K with a slight bias towards green and away from magenta. This is because the standard for print viewing booths is D50. Soft-proofing on a monitor set up for D65 can cause metameric failure when printing and viewing under D50 lighting. But as the use of prints continues to decline drastically in most consumers' buying habits, monitors set to D50 are becoming rarer and rarer, even among photo professionals, whose main outlet for displaying their work is increasingly on those same devices that graphic design people are targeting.

It also depends upon what the ambient light is in the location of the monitor and the color of the walls and ceilings that reflect that light. Our eyes adapt to the overall ambient light, especially when we first sit down at a monitor. The longer we sit at a monitor, though, the more our eyes will adapt to the light coming from the monitor, especially if there are significant areas of the screen that are neutral gray or white.

In the end you can only control what the image looks like on the monitor you use to edit it. If all of your own devices are similarly matched, then they'll all show the image near identically, allowing for the slight differences in color gamut each device may be capable of displaying.

You have no way of knowing whether your potential viewers will be viewing on a device with "blue off" enabled or not.

I tend to use D55 because that closely matches the ambient light in the room where I do my editing. It's also a compromise between editing for prints and editing for most handheld devices. I also disable any "blue light on" or "blue light off" or any other type of preset profiles on my monitors and in my GPU settings. My monitors are set manually using the monitor's "User" mode settings. I adjust the Red, Green, and Blue channels, brightness, and contrast controls while they are measured by a colorimeter. Once the monitor is as close to the target as possible, I then use the colorimeter and its software to generate a color profile to be applied by the computer's OS to make final fine corrections, which are rarely even perceptible when switching the new color profile "off" and "on" at the end of the profiling process.

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    \$\begingroup\$ Appreciate you coming in with D65 which was not part of the original question, but how does D65 relate to 100% DCI-P3 or Adobe RGB gamut? \$\endgroup\$
    – user610620
    Mar 10, 2023 at 15:55
  • \$\begingroup\$ D65 is not a color gamut, it's a target for defining what a display should emit when it's being sent a signal with all three color channels the same value. In other words, it's one of any number of answers to the question, "What color should the screen be when it's told to display white or neutral gray?" However, when the "center point" is moved around within a particular color space, the amount of "room" from that center point to the edge of the color space in each direction changes. \$\endgroup\$
    – Michael C
    Mar 11, 2023 at 0:55
  • \$\begingroup\$ DCI-P3 is a color gamut that includes a definition of the target white point as roughly 6300k and a slight bias towards green. Adobe RGB is a different color space that has no defined white point target. The user is free to decide where they wish to place the white point, though D65 or D50 are two of the most commonly used targets. \$\endgroup\$
    – Michael C
    Mar 11, 2023 at 1:06
  • \$\begingroup\$ As I wrote by mistake as a reply and not a comment before @MichaelC comments above: The final encoding whitepoint for theatrical exhibition is always that of DCI-P3, i.e. greenesh ~D63, but the adapting (creative) whitepoint of the imagery can be anything. \$\endgroup\$
    – Kel Solaar
    Mar 11, 2023 at 5:06
  • \$\begingroup\$ @KelSolaar What does theatrical exhibition have to do with editing photos for viewing on monitors and portable devices? \$\endgroup\$
    – Michael C
    Mar 12, 2023 at 6:15
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When there is an overwhelming color bias to what you are viewing it results in cone fatigue... the RGB (short/middle/long wavelength) receptors in the eye responsible for that color become tired/saturated. Which then biases your vision towards the opposite color (CMY).

I can't say which mode is "more deceiving"... it's extremely variable by monitor/software/intent. This is why most professionals color calibrate their displays to ensure all colors are as accurate as possible.

https://www.arvo.org/globalassets/arvo/advocacy/advocacy-resources/illusions/cone-fatigue-flyer.pdf

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  • \$\begingroup\$ It's not much of an answer to say "can't say" so how about edit your answer to hypothetically provide instructions for a typical video editing PC laptop set-up that must be color-calibrated to eliminate any blue light on and blue light off bias \$\endgroup\$
    – user610620
    Mar 10, 2023 at 15:58
  • \$\begingroup\$ @user610620, are you asking for how to calibrate a monitor? That depends on the hardware and software used... If you are asking "which set-ups" need to be calibrated; really all of them do for color critical work. \$\endgroup\$ Mar 10, 2023 at 16:40
  • \$\begingroup\$ @user610620 Start with a screen that allows one to turn off all of those "blue on", "blue off" options and use the manual controls to set contrast, brightness, and R, G, and B level independently. You don't calibrate a screen with bias built in. The best you can do is profile it. But the further from the target output the screen is before the profile is created and applied, the less effective the profile will be. \$\endgroup\$
    – Michael C
    Mar 11, 2023 at 1:00
  • \$\begingroup\$ @user610620 Are you doing photo editing, as your question indicates, or grading video as your comment above indicates? \$\endgroup\$
    – Michael C
    Mar 11, 2023 at 1:02
  • \$\begingroup\$ @StevenKersting Except our S/M/L cones are not most sensitive to R (640nm), G (530nm), & B (480nm), respectively. They're most sensitive to approximately 420 (blue-violet), 534 (slightly yellow green), & 564 (lime green) nanometers, respectively. They were called that long before we were finally able to isolate exactly to which wavelengths each type of cone is most sensitive in the 1990s, but it's a highly inaccurate and misleading description to continue calling them R/G/B cones. \$\endgroup\$
    – Michael C
    Mar 11, 2023 at 1:13

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