Illusion of DEPTH

Vision, like all other senses, evolved to help us survive.

In reality, there is nothing like "light." Electromagnetic waves, emitted by energy sources or reflected from materials, activate sensitive retinal cell proteins in our eyes, and our brain "sees" things.

Colors are processed pixel-by pixel by the optical center. Everyone has a color memory that maps emotions. 

Colors relate to their surrounding colors and create an illusion of distance. The three columns of identical colors interact with the gradient background and present themselves differently. It's easy to notice how these rectangles 'feel' different from top to bottom. 

Thing to note here is association between hues and perceived darkness. I use such illusory compositions to enhance the mood of a painting.