We are taught the rainbow is composed of red, orange, yellow, green, blue and violet, and sometimes that there are invisible colors, infrared and ultraviolet, on either side. And we learn that ...

For example, a red object appears "redder" on a green background than on a white background. In other words, neighboring colors can change how we perceive certain hues.

In the ocean, for instance, red objects appear to fade more than blue objects when viewed from farther away. Out of water, the color of objects appears more or less the same regardless of the ...