Cross's photograph of two polished spheres under one light, a white one at the left, partly behind the red one, its lit side lost against the white ground so that mainly its shadow side and cast shadow show, and a red one in front with a bright side, a shadow side and a cast shadow; a stick of charcoal lies in the red sphere's shadow.

Concept · Foundations

Local Value and Light

Local value is a surface's own lightness or darkness, apart from the light falling on it; light and shade are added on top.

Cross's photograph shows a white sphere and a red one under the same light. He notes both show the same pattern of light and dark, but the range on the red one is narrower.

  • Cross pointed out that the lit side of a dark object can look lighter than the shadow side of a light one.
  • The highlight shows more strongly on the dark sphere, against its deep color.
  • To judge a tone, ask two questions: how light is this surface, and how much light is it getting?

See

Image: Internet Archive · Public domain (published before 1931)

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