This system closely approximates the way red, green, and blue screen phosphors reproduce colors on a computer monitor. Painters and other visual artists usually prefer to specify colors by hue, intensity, and value. Hue refers the pure color of an object and is what most people think of as the definition of color. Selecting the appropriate hues within a scene can be used to set the mood of the image. Bright oranges and yellows create cheerful moods, reds are exciting, blues and greens are calming and serene, violet is mysterious.
Intensity refers to the strength the hue.
Browns are low intensity reds. Changes in intensity can be used to reveal form as in the illustration to the left. Foreground objects tend to have higher intensity colors than background objects. Value is variation in lightness and darkness. Changes in value are the primary means of shading objects to convey form.