The color wheel can be divided into two halves based on the effects of the colors in each half on the viewer’s feeling of warmth and coldness. The warm half ranges from yellow to red-purple. Whereas, the cold half ranges from yellow-green to purple.

The contrast between cold and warm colors relates first and foremost to our overall feeling about the coldness or warmth of an image. However, on a second level, it also influences the viewer’s feeling of depth. When placed in front of warm colors, cold colors seem to merge into the background of an image.

Meanwhile, the other way around, warm colors in front of a cool-colored background seem to move into the foreground. The most powerful depth effect of this type is achieved between the complementaries red-orange and blue-green.