4. Our color vision is limited

- Our vision is optimized to detect contrasts, especially edges, not absolute brightness
- Our ability to distinguish colors depends on how colors are presented. Heavily affected by the surrounding environment
- The user's display and viewing conditions affect color perception
- Some people have color blindness

 

light-receptors: Rods and Cones

Cones detect colors, there are 3 types of cones for detecting short, medium, and long wavelengths
Activating single type of cones enhance humans perception of the color. ex) multiple L-wave cones make the viewer's perception of red more strong. - Brian P. Schmidt (2019)

_note About cones - UNM website (cannot find the source though) Study more later_note 20240403

Rods are useful for low-light
Rods only function at very low light. (Humans in modern industrialized area wouldn't use it)

 

Vision is optimized for detection of edges, not brightness

Not like a mechanical sensors, human vision system is sensitive to contrast, edges, and rapid changes. As it helped humans to survive in primal environment to detect predator or threat easily. Human color vision works mainly by subtraction: red - green and blue - yellow. 

 

Discriminability of colors depends on how they are presented

Saturation
Less saturated colors are hard to recognize the difference

Size
Smaller objects are relatively harder to distinguish the difference

Space
The more separated colored objects are, the more difficult to find difference

 

 Color blindness

_note - Tool I have used to create Data Visualization color palette
Viz Palette - different visualization style samples and color blindness samples
Chroma.js - automatic palette generation based on picked colors, and HSL chart about the palette
Pilestone color blindness simulator - just simple simulator to show how people with color blindness people would see the uploaded image

_note - color vision deficiency affects approximately 1 in 12 men (8.3%) and 1 in 200 women (0.5%) worldwide, with similar percentages expected in the U.S. for red-green color blindness. Blue-yellow color blindness and complete color blindness are much rarer in comparison.

 

Other factors affect color recognition

Variations in colored displays (display device differences)
What you designed on your computer might not look the same on your phone due to this.

_note - most of the recent, 2024, apple products use P3. It will look very similar on those two comparison.
Windows, it depends on your monitor quality, however, you can calibrate yours simply or with a tool. However, I suggest just use your phone to check the color if needed. Except very specific or rare cases, most of the users won't even notice.

Dark mode
_note - I haven't studied about this. But I assume it's due to the difference between the excessive amount of brightness and extremely dark, especially with OLED screens, 

Display angle
based on the panel type and quality of the display. It will affect the color in various ways. ex) when you watch your TV from the side, color looks washed off. sample - rtings review on a display