Physics: What color is it really?

We all know what happens when you mix yellow and red paints...what happens when your brain does the mixing?

This week we did 2 mini-experiments to investigate how we perceive color. The first one was with spinning color wheels - discs with various color patterns, which when spun reveal different colors. The second involved examining magazine pictures under the microscope.

Both experiments demonstrate that what we see is limited by how much information our eyes and brain can take in at once. With the spinning color wheels, when we see 2 colors within a short period of time, our nervous system combines the colors. Pictures in a magazine, like the paintings of Seurat (did I mention we got all cultural and talked a bit about pointillism?), are actually made up of patterns of tiny dots. When the dots are small and placed closely together, your brain can't process them separately and instead combines them to produce the experience of various colors. What is especially cool about the magazine pictures is that no matter what color you "see," the image itself is actually made up of just 3 colors: magenta, cyan, and yellow (aka red, blue, and yellow) plus black. By producing images that include different ratios of the primary colors, you can get just about any color.