Colorized pixs from the past

[Snellius]

22. No. Not like that. Only for color blindness.

Saturation is not the color, the hue, whether blue or green, but the intensity of the color. Fire engine red is more saturated than pink. The hue of both is still red. A saturation of 0% is always a shade of gray. Saturation is used all the time in graphics. The relative effect for any observer is the same.

With normal vision, we do see colors slightly differently but the comparative relations between the colors is pretty much the same. The whole perceivable spectrum for each person can be slightly shifted. But blue will still be the complementary opposite of orange. (If you stare at a color long enough to fix it as an after image and shut your eyes, you will "see" its complement created in the brain.) In absolute terms, whether one person's blue is another's blue is hard to compare. Tests can be done how each relates the color to another color. But since we can't see ourselves seeing or see what someone else sees, colors are relative. And only created and processed in the eye and the brain. They do not exist in the real world. Just properties of what wavelengths are emitted, reflected or absorbed. Try to imagine a color you've never seen.

Apologize for the lecture. Have always been fascinated by how we see.