Motion and colours

Artists use the technique of “equiluminance” to blur outlines and suggest motion. We cannot perceive the edges of objects where object and background have the same luminance. If parts of a painting are equiluminant, their positions become ambiguous. They may seem to shift position or to float. Equiluminant colours have long been recognized by artists as being special because they can generate a sense of vibration, motion or sometimes an eerie quality. Use of equiluminance in painting can make sunsets twinkle and flowers shimmer.

The choice of colors can also suggest motion. To create the illusion of an advancing object, use warm colours in the foreground (on the object) and cool colours in the background. If the object is receding, use cool colours in the foreground and warm colours in the background.