Light and shadow make a flat drawing look three dimensional. When an artist shades a sphere, cube, or cylinder, they are showing how light travels, reflects, and is blocked by objects. A strong light source from the upper left creates predictable highlight areas, midtones, core shadows, cast shadows, and contact shadows.
Understanding these patterns helps students draw forms that feel solid and believable.
Key Facts
- Value means the lightness or darkness of a tone, often arranged from 0 = black to 10 = white.
- Light travels in straight lines, so cast shadows extend away from the light source.
- On a sphere, the highlight, halftone, core shadow, reflected light, and cast shadow form a smooth value gradient.
- On a cube, each plane usually has a different value because each face meets the light at a different angle.
- On a cylinder, shading changes gradually around the curved side but the top ellipse may show a separate plane value.
- Stronger light contrast gives sharper shadow edges, while softer or larger light sources create smoother transitions.
Vocabulary
- Highlight
- The highlight is the brightest area on a form where the surface faces the light most directly.
- Core shadow
- The core shadow is the darkest band on the form itself where the surface turns away from the main light.
- Cast shadow
- A cast shadow is the dark shape projected onto another surface when an object blocks light.
- Reflected light
- Reflected light is faint light that bounces from nearby surfaces back into the shadow side of an object.
- Contact shadow
- A contact shadow is the very dark area where an object touches the surface beneath it because little light can enter that gap.
Common Mistakes to Avoid
- Putting the cast shadow on the wrong side of the object, which breaks the logic of the light source. If the light comes from the upper left, the cast shadow should generally fall down and to the right.
- Making every shadow the same darkness, which flattens the drawing. Core shadows, cast shadows, reflected light, and contact shadows should each have different values.
- Outlining the edges too heavily, which makes forms look like symbols instead of solid objects. Use value changes and edge control to show form instead of relying only on dark contours.
- Forgetting reflected light in the shadow side, which makes rounded forms look dull or cut out. Reflected light should be lighter than the core shadow but darker than the lit side.
Practice Questions
- 1 A value scale runs from 0 = black to 10 = white. If a sphere has a highlight value of 9, a halftone value of 6, a core shadow value of 2, and reflected light value of 4, list these regions from lightest to darkest.
- 2 A cube is lit from the upper left. The top face is value 8, the left face is value 6, and the right face is value 3 on a 0 to 10 scale. What is the value difference between the brightest and darkest faces, and which face should appear most in shadow?
- 3 A sphere, cube, and cylinder sit on the same tabletop under one strong light from the upper left. Explain how the cast shadows and contact shadows should be arranged so the objects appear to share the same space.