Light and shadow sketch is the basis of realistic oil painting. Through the preparation of the sketch, the painter can have a deeper understanding of the object from the aspects of overall composition, local details, scene space and line realism.

Light and shadow sketch is the further development of structure sketch. This kind of sketch is characterized by using light and shade on the basis of lines as the main means of expression, focusing on light and shadow changes, and emphasizing the lighting effect of objects.

The performance of light and shadow sketch lies in the description of light and shade.

The scoring point of sketch is firstly the overall composition, creative thinking and visual impact of the picture, secondly the black-and-white treatment of the picture, and finally the overall shaping and layering of the picture.