Colors Used

Compare the contrast effects of different color backgrounds for the same red square.

Red appears more brilliant against a black background and somewhat duller against the white background. In contrast with orange, the red appears lifeless; in contrast with blue-green, it exhibits brilliance. Notice that the red square appears larger on black than on other background colors.

The small purple rectangle on the left appears to have a red-purple tinge when compared to the small purple rectangle on the right. This demonstrates how three colors can be perceived as four colors.