What is the role of light and shade in painting?

The relationship between light and shade is a very important part of sketch painting, and its most basic function is to express the relationship between volume and space. The relationship between light and shade is divided into five levels, which is often said: "Five tones of light and shade." Next, the teacher of Boyi Beijing Studio will explain the five tones of light and shade in detail:

The five tones of light and shade include: highlight, the brightest point on the light receiving surface.

Bright surface: refers to the layer between the highlight of the light receiving surface and the dark gray surface.

Gray surface: refers to the layer between the bright surface and the dividing line between light and dark.

Light-dark dividing line: refers to the turning point of surface light and dark, and generally the light-dark dividing line is the heaviest place.

Dark side: includes the backlight surface, reflection and projection of the object.

In fact, these five levels can be summarized as three levels: bright surface, gray surface and dark surface. Of course, these five tones can also be divided into more and more detailed levels, which can be summarized and distinguished according to the meticulous degree of painting.

Let me explain the relationship between light and shade of objects through cubes first. There must be light to get light and shade, so I will assume a light source direction now. The surface where light can shine is called the light receiving surface, and the place where light cannot shine is called the backlight surface. The backlight surface includes dark surface and shadow, and the light receiving surface includes bright surface and gray surface. The shape of shadow is directly related to the direction of light and the occlusion of objects. According to the principle of being close to reality and far from emptiness, the contrast near the front, especially near the boundary between light and dark, should be clear, while the contrast behind should be weak and vague. And the closer the shadow is to the object, the darker and clearer it is.

As we all know, the earth is always half the earth during the day, half the earth at night, and it is morning and dusk when it is close to the night. The light is usually brightest at noon. The same is true for drawing spheres. Half a sphere is bright and half a sphere is dark. The position of the bright part perpendicular to the light is the brightest, and the closer it is to the boundary between light and dark, the darker it will be. These places near the dark parts are called gray surfaces. The reason why the dark part is not pure black is because it is also influenced by reflection and other environmental light sources.