Why is it required that when sketching a plaster head, the area occupied by the picture part should not be less than one third of the drawing paper, but not more than one half at most?

When sketching a plaster head, it is required that the area occupied by the picture part is not less than one third of the drawing, but not more than one half at most. The main reasons are:

1. The painting method of plaster head needs to pay attention to the relationship between the whole and the part. The overall relationship refers to the overall effect of the picture, such as the light and shade of the picture, the sense of space and so on. The local relationship refers to the details and structure of the plaster head, such as outline, muscles, bones, etc. In order to deal with the relationship between the whole and the part, it is necessary to divide the picture into three parts: head, neck and base. Among them, the head is the main body of the picture, which needs to occupy a large area, the base is the support of the picture, and it also needs to occupy a certain area, while the neck is the key part connecting the head and the base, which needs to be properly highlighted. Therefore, the area occupied by the screen part shall not be less than one third of that of drawing paper, so as to ensure that the screen has enough space to show the overall effect.

2. The maximum area occupied by the picture part is not more than half, so as to ensure the layering and space sense of the picture. If the picture is completely occupied by the head, it will make the picture too cramped and depressed, lacking a sense of hierarchy and space. If the picture is too large, the size and position of the head are not prominent enough, which will also affect the sense of hierarchy and space of the picture.

When sketching the plaster head, we need to observe and understand the overall effect and structural characteristics of the plaster head, grasp the relationship between the whole and the part, and pay attention to highlighting the connection between the head and the neck, as well as expressing the layering and three-dimensional sense of the head.