Still Life and Object Study: Shading, Light and Shadow, Texture
Still life tests whether you can describe three-dimensional form with value alone, before texture and detail.
The light logic
With a single lamp, every form shows a specular highlight, mid-tone (local value), core shadow at the terminator, reflected light inside the shadow, a cast shadow and a dark occlusion shadow where object meets ground. Cast shadows are darkest and hardest-edged at the contact point and soften and lighten with distance. Squinting collapses detail and shows whether the light family and the shadow family stay separate.
Value
Build a nine-step value scale and stick to it. Never place a highlight outside the light family or a white inside the shadow family - the commonest failure is reflected light bright enough to break the form.
Texture and edges
Hatching, cross-hatching, stippling and scumbling describe surface without destroying value; keep the underlying value even under texture. Vary edge quality: hard at the terminator on a matte sphere, soft at the far end of the shadow, lost where the form turns into the background.
Worked example
A white cylinder on grey cloth: lay a flat mid-tone over the whole body, lift the lit side with a kneaded eraser, then build the core shadow as a vertical band with a soft upper edge and a harder lower edge. The cast shadow is an ellipse whose axis follows the light direction, not the cylinder's axis.
Traps
Drawing outlines around objects; letting cast shadows float; making every edge equally sharp; filling shadow with black instead of a dark version of the local hue; finishing one object completely before the next, which destroys the overall value plan.