A peacock feather in sunlight shifts from blue to green to bronze as you turn it. Photograph it, and this shimmer collapses into one angle, one exposure, one compromise.A digital image is not a record of what your eye sees. The standard color space that most digital images use was built for an older display world, when cathode-ray tube monitors swept beams of electrons across phosphor-coated glass. This standard color space made color predictable across many devices, but the compromise was a narrower range of colors for screens, cameras and image files to share.Whatever the screen offers feels complete. It is not that your eyes cannot see more; digital images give them less to work with.AdvertisementAdvertisementI teach a class about color at the California Institute of the Arts called Plastics, Neon, and Psychedelia, which covers the many ways color is produced: by materials, by light, by screens and by the mind.I also have a condition called deuteranomaly, which changes the way I discriminate color, though not in the way you might imagine. A deuteranomalous eye does not simply lose color distinctions – it remaps them.Vision researchers in Cambridge showed in 2005 that deuteranomalous observers can reliably distinguish khakis and olives that look identical to people with standard color vision. I have mistaken a traffic light for an overhead streetlamp while driving at night, but my color vision is not a shrunken copy of ordinary vision: It is a different map of the same ground.While my eyes leave some colors uncertain, they sharpen other distinctions. Screens impose another kind of limit, though more quietly: They organize color according to their own rules, then offer that version as complete. My eye and the screen are both maps that include and exclude differently. Mine trades some distinctions for others. The screen trades range for reliability. The question for any color system is not whether it is accurate but what it keeps.From wild green to screen greenMy neon pothos houseplant is so green that it seems to generate its own light. Photograph it with a smartphone and the result is fine: The leaves are green, the picture makes sense. But the green in the photograph is not the green on the plant.AdvertisementAdvertisementLook at the photo. Look at the plant. Then look at the photo again. The photographed leaves are muted, but not evenly. Some greens flatten while others appear boosted, as if the phone were trying to compensate for what it cannot show. The leaves on the actual plant are electric. No phone I own, no printed page and no Instax print has captured that green, though the Insta …