>>4216950>>42169652/?
Once an SPD is measured or known, we must calculate "standard observer" coordinates. These curves are based on measurements done in a lab. An observer was placed in front of binoculars where one eye was looking at a spot color on a white background with a known SPD and the other eye was looking at similar spot only composed of additive mixtures of red, green, and blue lights. The lights were then adjusted until the observer said the colors matched. This was done with hundreds of colors and several dozen observers. These curves roughly correspond to our eye's short, medium, and long cones, but not exactly. Note that there are infinitely many SPDs that have the exact same standard observer coordinates. These are called metamers. While they might appear the same under one light source, they might look totally different under another. This is called 'illuminant metamerism'.
This is what I call "level 1" of color, bc it describes our color perception in a vacuum.
