An object's own lightness vs. the light falling on it (a white shirt in shadow is still white)

Separate an object's inherent lightness from the light falling on it, so values show both material and illumination.

What it is

Each surface has an inherent lightness called its local value. A white shirt is light and charcoal is dark, regardless of the lighting.

Illumination is the amount of light reaching a surface. In a painting, the visible value reflects the object's local value and the illumination it receives. A white shirt in shadow can appear darker than a black shirt in direct sun while retaining its material identity.

Why it matters

Separating local value from illumination helps materials retain their identity as lighting changes. Confusing them can make a white shirt appear dirty or cause shadows to lose their relationship to the material.

You can check it when

• ✓Classify dark and light areas in a reference by material value or by the illumination reaching the surface.
• ✓Paint the same object under 2 lighting setups, and check whether it reads as the same material in both.
• ✓Compare shadow-side values with the object's local value and check that they have not collapsed into a generic dark.

Related skills

• Seeing value (independent of color; accurate observation; value scales)
• Separating the light family from the shadow family
• Local color under light and shadow
• Differentiating materials through value, edges, reflections, and texture
• Direct, diffuse, ambient, and sky light
• The shadow family (core, form, cast, contact/occlusion)