Detailed explanation of contrast application in photographic composition

Contrast between light and shade: for example, a ray of sunlight falls on the main body and the rest is relatively dark, for example, a stage spotlight highlights the main body.

Far and near, size and height, these contrasts highlight the theme of near, big and high relative to far, small and low.

In short, the contrast method is to find a reference in the picture as a foil to highlight the main body.