Colorblindness: will digital displays (RGB) look equivalent to print (CYMK)

Question

I ask this as a non-colorblind scientist that tries to be conscious about accessibility when creating scientific figures for manuscripts, posters, etc. To do this, I make sure to use color palettes created to be colorblind friendly (at least to the most common types), and use tools like visual filters in image editors to try and get an idea of what it might look like for colorblind people. The problem is that these tools are all digital.

Given that my work can appear in both digital and print mediums, I'm curious if the differences in how they visually produce color can lead to visual differences for colorblind people. Specifically, I'm thinking of digital displays that use a RGB additive model vs printing that uses a CMYK subtractive model. Given that the cones of the eyes are only sensitive to certain wavelengths of light, and given that many colors we perceive can be recreated using different wavelengths of light (e.g, there's blue wavelengths, but yellow + green can also appear blue), are the wavelengths we receive from digital screens (RGB) and print (CMYK) going to compatible such that checking my images for colorblind friendliness on my computer will work for the print version? And how dependent (for print) will this be on different types of light sources that emit different spectrums?

_{I'm kind of surprised there isn't a colorblindness tag here}

Answer 1

Usually when graphic designer want to check if his print is ok for colorblind people they just change it to grayscale. If there is enough contrast and the message is readable then it's (usually) ok for all kind of colorblindness.
I have a "colorblindess" in part of green spectrum. A very dark green is not seen by me as green. On screen it's Black(-ish) and in print it's brown(-ish). In nature the green is just more juicy as there is bigger contrast.
In print I see everything what make "dirty black" (or registration) minus the green. On screen this color is made by lighting G and dimming R and B. It's not just Cyjan + Yellow +black in print.

There are also Ishihara Test Chart Books to check for color definency. There is 38 plates in there. 38!. And sometimes I don't see more than usual and sometimes I see all. Why? Because some of them are quite old. The paint have faded, the paper have changed color. The source light change (from natural with sun to cloudy one, Fluorescent to LED).

So as a designer I don't care about tweaking and adjusting too much. It become a habit to not have too much colors in infographics (and IMHO 4-5 color ones work the best anyway). If the grays work on screen the printed version will work as well IMHO

Answer 2

Ok, you have to understand that color as precieved does not have anything to do with wavelengths. Its true that different spectral spikes make different colors. But that does not mean all same looking colors have same spectral distributions, unlike what quick glance in physics let you believe.

Simply CMY colors are the very closely the same wavelengths as RGB. Cyan is just a Red filter, Magenta Green and Yellow Blue filter.

What you see is quite close to correct even in print. (Remember its still just a simulation, not what is really going on)

Answer 3

This is only a comment, but too long to be written as a comment.

The causes of color blindness vary. The color selective sensor cells in the eye have color filters which make them able to coarsely make difference between separate wavelengths. The wavelength ranges of the filters are wide and they overlap, but the processing in the brain makes possible to see a wide variety of colors.

Possible mechanisms of color blindness:

1) The person has colored material in his eye in front of the color selective cells, it's like you watched through colored glass and a part of the wavelengths would be lost before they reach the sensor cells

2) The person has radically abnormal color filter pigments in his color selective cells, so the postprocessing in the brain is based on wrong parameters, some wavelengths can be lost and the overlapping of the bands can be too wide.

3) The signal routing between the eye and the brain causes crosstalk or transmission errors

4) The postprocessing in the brain has a bug

Faults 3 and 4 do not generate differences, if the color is seen wrongly in a CMYK print, it's seen wrongly also on the RGB screen

Faults 1 and 2 affect easily differently when one compare their effects on RGB screen images and CMYK prints. Some RGB screens send filtered white light. The white background light can have wide spectrum without narrow band peaks. A color blind person must see those RGB colors equally with the CMYK print colors which are watched in white light without narrow band peaks.

Light which contains only some narrow band peaks can be seen as a predictable color if the powers of the peaks are selected right. Some led displays really produce only 3 wavelengths and they still produce full sRGB range colors. Also a strong effectively produced LCD backlight can have only narrowband peaks. The poor spectrum discrimination capability of our sight is fully utilized. A color blind person with faults 1 or 2 can see very different color when he compares two colors which normal persons see as the same, but one of the colors has a peakless wide spectrum and the other contains only narrowband peaks. That's because those narrowband peaks are designed for normal color filtering in the eye.

You can get an idea of the effect if you can compare natural color materials in daylight and in old style powerful white street or industry hall lamp light which has narrow band peaks. Many natural or badly designed artificial color materials have reflection and absorption peaks which makes their color unpredictable in white light which contains only narrow band spectrum peaks.

Unfortunately the categorization of the color blindness cases is based on which colors cannot be seen and which look the same on certain test images. I cannot tell how one can find the physical fault numbers 1...4 that I used when he sees a Latin name of a color blindness case.

The story above is only simple everyman-level reasoning. I guess you should ask color blindness experts to get valid quantitative knowledge. Most of us make and mangle images and layouts, some of us are creative artists, too and some of us make succesfully money with graphic works. But very few of us have some scientific quality knowledge of sight faults.

Answer 4

Strong answer: NO they look different on screen vs. paint or ink. Save in RGB for video/pics/anything digital, save to CMYK for printing. you can save the same file in both formats just don't forget to name them. BTW I am "color blind"

I'm Dan, I am red-green photo deficient. I see all colors BUT I see red and green just about 25% less than the "normal eye" person

To all us who see color color Semi, Full, idk how to type brail but you too:

This reply is 2 years late but this is the first time I've seen post for me so shut it :P

BTW: After all that time with no response to this "statistics dude" above me I think I should say something for anyone else who looked this up lol.

As a red-green deficient person of sight I have always wondered WTF my friends see. As a kid I once made an American flag with a purple background for the stars... I thought it was blue! Now I see the difference but back then it wasn't and I had a realization.

I SEE DIFFERENTLY!!! Greens for me are so vivid yet reds are a bit meh. Racer red FTW! Purple is more like a deep sea blue while maroon is more of a reddish murky brown.

Unless they are right next to each other I may not be able to immediately tell you grass green vs florescent orange... tho i see the green and the red in each it's the hue that gets me, neither stand out.

Anyways, to get to the point:

When I was in color theory class I could match colors OK with actual paint. I made weird colors I liked but that's besides the point.

Using color theory on my digital projects was weirder... I would make things that looked good to me but my colleagues would tell me is oversaturated or totally out of color scheme. At that point we were using Photoshop in just normal RGB mode.

I learned about CMYK format later on in my schooling and found out you could switch from RGB to CMYK and literally the color wheel went from a gradient to straight up definite color differences. I was able to match colors easily, it didn't make anything more vivid or make me see different colors, it just helped me actually define the color seperations or merges.

I WOULD RECCOMEND ANYONE WITH COLOR DEFFICIANCIES OR BLINDNESS TO TRY SWITCHING TO CMYK WHEN DOING DIGITAL ART, ITS INSANE!

Just remember to get a second opinion when you convert to RGB for the save file.

Hope this answers a question!!! -DeezyBeezy :3