What is the area of an artwork called that is occupied by the primary subjects?

Positive space.

Explanation:

The area of an artwork occupied by the primary subjects is called positive space. It’s the main focus of the picture or artwork. On the other hand, the background or everything which is not primary subject, is known as negative space. The positive and negative space are used together to make a composition and create meaning. They are both equally important, as the negative space helps support the positive space. They can be used in different proportions to create different climates and situations.

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