We see color through three different lengths of cones in our eyes. That is why we say there are three primary colors, blue, red, and yellow. Most birds have four lengths of cones so they see a fourth primary color in the ultraviolet range. Just like blue and yellow combines to make green, ultraviolet light combines with the other three primary colors for birds to make combinations we cannot imagine. That means that bird’s feathers often have an ultraviolet color component that we can’t see but birds can.
I’ve been thinking how to express this in my work with feathers. I began by thinking about some ways we express the color spectrum: rainbows, color charts, color wheels, graphs, and prisms. So here is a take on it in this piece.