In his treatise on painting, titled Della Pittura ("On Painting"), Alberti proposes that "the whole of painting" consists of three parts: circumscription, composition and the reception of light.
Circumscription, according to Alberti, is "the recording of the outlines, and if it is done with a very visible line, they will look in the painting, not like the margins of surfaces, but like cracks. I want only the external outlines to be set down in circumscription; and this should be practised assiduously."
Composition is the way everything in the painting fits together, "all the surfaces in their correct relationship."
The reception of light is connected with observation of the colors in the painting. Alberti said that color cannot be perceived without light, that it "receives all its variations from light."
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