Our brains interpret our sensory data by filling in the blanks. Take a look at this image of strawberries for example.

What color are the strawberries? Your brain is probably telling you that they are red or reddish, but there is no red in this image. 

From Neatorama: 

"We know that strawberries are red, or at least they should be, so that's what we see. Professor of Psychology Akiyoshi Kitaoka (previously at Neatorama) created this image of strawberries that contains no red pixels at all. This is an example of color correction in our brains. We essentially filter out colors that make no sense to us in order to see things as they should be. Carson Mell isolated the colors found in the strawberries, and none of them are red."

This is a fascinating topic as it goes to the heart of what light is, and how we perceive light as humans. As an optician I find this particularly fascinating. Our brains compensate for a lot of missing visual data. There is more on this post submitted by people that provide other image details. Great read!

By the way, if you are interested in this topic I would strongly recommend watching Cosmos: A Spacetime Odyssey as much of this fantastic show delves into light and optics. Our understanding of light/energy, optics, and human perception are the cornerstones of modern science.