Light-dark contrast is the most plastic contrast — white and black are its poles with an infinite gray scale between

Light-dark contrast works through the luminosity axis from white to black, including all achromatic grays and the differing natural luminosities of chromatic colors. Key facts: (1) Yellow is the lightest pure hue; violet is the darkest. Red is darker than yellow but lighter than violet. (2) Neutral gray is characterless and easily influenced — adjacent color shifts it toward the complementary. (3) Pure saturation peaks at different points on the gray scale for each hue (yellow peaks at step 4 of a 12-step gray scale; violet at step 10). (4) Light-dark contrast produces plastic, spatial, and modeling effects — it is how form is traditionally described in painting. (5) Equally brilliant chromatic colors eliminate light-dark contrast between them, making them appear flat. Managing the natural light values of hues is a prerequisite for intentional light-dark composition.

Examples

In shaders: mapping luminosity dot(col, vec3(0.299,0.587,0.114)) reveals the light-dark structure independent of hue. A gradient from pure yellow to pure violet traverses the maximum natural light-dark span between pure hues.

Assessment

Place yellow, red, blue, orange, violet, green in order from lightest to darkest; explain why Rembrandt’s radiant reds require very dark surroundings to glow; define the condition under which achromatic grays lose their neutral character.