In Van Gogh's early letter to his younger brother Theo, there was a passage: "The three primary colors are only red, yellow and blue, and the synthetic colors are orange, green and purple. So, with a little black or white, there will be endless grays: red gray, yellow gray, blue gray, green gray, orange gray and purple gray. It is difficult to describe accurately, such as how many kinds of green and gray are there?
It's really changeable. But all color chemistry is no more diverse than those simple primary colors. In short, simple colors are more cost-effective than 70-color pigment combinations, because you can mix more than 70 combinations of tones and intensities with three primary colors and black and white. "
It can be seen that Van Gogh's profound grasp of color is undoubtedly one of the reasons for his great artistic achievements later, especially the last sentence, in which simple colors can be mixed with black and white to produce endless changes. We can see his concrete application of this sentence in many of Van Gogh's later works.
In Van Gogh's works, there are generally no more than two main colors. Take "The Wheat Field and the Reaper" as an example, the whole painting is mainly yellow, only the blue mountains and roads are simply separated, except the golden wheat field.
The rest is like adding a yellow mask, so the sky turns blue, the mountains, trees and people all glow with some yellow light, and the sun and the soil in the wheat field directly turn yellow, thus making the picture visually unified and harmonious.