I drew a picture of a house on a hill, with some clouds and a tree. I then loaded this into processing... pulled out the colour values for each pixel and redrew the images 8 more times.
The results made me think about how the human mind might break down an image in an attempt to identify different parts.
Each of the images provide a different set of contrast for different elements.
The sky shows up in bright blue on the 9th / bright white on the 6th image, leaving a dark siloette of the house on the hill.
The mostly red house shows up well on the green copies 5 and 8, as it contains the least amount of green in the image and has a good contrast with its surroundings.
The same goes for the green tree on the red copies 4 and 6, a distinct lack of red creates a dark contrast. The clouds also show up well (bright) on this image as they contain more red then blue/green and stand out from the sky that surrounds them.
Our eyes can detect red, green blue colours... as well as light and dark. Perhaps for futher experiments these are the five areas that should be compared.