The color is different from the color on the palette. Painters never put the color on the palette, that is, factory-made paint, intact on the canvas. These colors must be painstakingly art to be carefully modulated, in order to achieve the color of soft, realistic, color and color with the harmony between the unity. This is what people usually call the tone or tone. The color painting can not be random patchwork of color, can not be numerous and complicated, dazzling, and should form a color can reflect the tendency, and change no reason, subtle and delicate picture effect. Hue is the soul of oil painting. In addition to the above requirements, the painting also pays attention to composition, stroke, rhythm and so on. The appreciation of oil painting is mainly from five aspects: the relationship between content and form, color, composition, the use of contrast, implication, symbol and subtle use of light and so on.