Sketch, broadly speaking, refers to all monochromatic paintings, which originated from the cultivation of western modeling ability. Sketch in a narrow sense refers to the painting training process used to learn art skills, explore modeling rules and cultivate professional habits.
In short, sketch is a kind of monochrome painting. However, this is not entirely correct. After all, sketch covers too many things and solves too many problems. Sketching process is a comprehensive thinking activity that considers many problems at the same time. At present, all majors in art colleges take it as a basic course, although each major has different emphasis, such as oil painting emphasizing volume and tone, Chinese painting emphasizing lines, printmaking and design emphasizing structure. But the commonness of sketches is similar. At the same time, sketch, as an independent art type, has its unique artistic value. Of course, there are not many specialized sketch artists, most of whom are part-time. For example, the master's sketches are already very valuable, and you don't have to distinguish between basic sketches and independent works of art, even if these sketches seem to be few, the skill behind them is also very good. Sometimes a random undulating line reflects the artist's profound understanding and mastery of modeling, structure, characteristics, rhythm, charm and art history.