Light does not just make a round form "light on one side and dark on the other." It moves across the surface in a series of values that artists name. Learn them on a ball, and you can find them on an apple, a head or a vase.
| Part | What it is |
|---|---|
| highlight | the brightest spot, where the light reflects straight toward your eye |
| light | the side facing the light |
| halftone | the middle values where the surface starts to turn away |
| core shadow | the darkest band on the form, where the surface turns away from the light |
| reflected light | a dim glow inside the shadow, bounced up from the table or nearby things |
| cast shadow | the shadow the form throws onto the table |
| occlusion shadow | the darkest line, right where the form touches the table |
Key idea
From the light into the shadow: highlight, light, halftone, core shadow, reflected light, and the cast shadow on the ground. Reflected light is always darker than any value in the light.
Why it works
The more directly a surface faces the light, the more light it receives. As a ball curves away, each part faces the light less, so the values step down until the core shadow, where the surface turns fully away. Past the core, light bounced from the table brightens the shadow a little. That bounce is weak, so reflected light stays a shadow value.
Worked example: Darker or lighter
Which is darker: the reflected light, or the halftone?
- The halftone belongs to the light side.
- Reflected light belongs to the shadow side.
- Every value in the shadow is darker than every value in the light.
Answer: The reflected light.
Common mistake
People make the reflected light as bright as the lit side, and the ball looks like it glows or turns to glass. Reflected light is always darker than any value in the light. Check by squinting: the whole shadow side should read as one dark shape.