The shadow family (core, form, cast, contact/occlusion)

Distinguish core, form, cast, and contact shadows, then place each to describe solid, grounded forms.

What it is

Core shadow is the band where a rounded form turns farthest from the light. It sits just past the light-shadow edge and is often the darkest part of the object. Form shadow is the full area turned away from the light, including the core and surrounding softer darkness.

A cast shadow appears when one object blocks light from reaching another surface. It belongs to the caster but falls on the surface it reaches. Its shape follows the caster’s silhouette. Its edges become sharper or softer based on the distance from the caster and the sharpness of the light source.

Contact or occlusion shadows appear where surfaces touch or nearly touch, such as feet on the ground, a cup on a table, or touching cloth folds. These tight, dark accents show contact, anchor objects to surfaces, and separate layers that could merge. In your painting, use broader, softer shapes for form shadows, directional shapes for cast shadows, and small, dark accents for contact shadows.

Why it matters

Separating shadow types helps maintain solid volumes, show weight, and establish light direction. Weak control can flatten forms, make objects appear to float, or reduce the connection between a caster and the surface receiving its shadow.

You can check it when

• ✓Label dark areas in your own painting as core, form, cast, or contact/occlusion shadows, then compare each label with the reference.
• ✓Strengthen one shadow type at a time and identify its specific effect, such as improved grounding from contact shadows without changing the full value range.
• ✓Match cast shadow shapes to the caster’s silhouette and position. Check that their edges change with distance from the caster or with atmospheric space.
• ✓Place contact shadows as small, controlled accents at touch points. Check that they are darker than nearby form shadows and keep objects from appearing to float.

Related skills

• Cast shadows (direction, softness)
• Source size → hard vs. soft light
• Bounce/reflected light and ambient occlusion
• Separating form edges from cast-shadow edges
• The light family (halftones, highlights, speculars, reflected light, terminator)
• Separating the light family from the shadow family
• Plane analysis and turning form with value