The blue tone is mainly blue, supplemented by other colors.

First of all, "hue" depends on the strong color of the picture, or it occupies a large area of the picture, giving people the concept of main color. Can be based on hue; Yellow, green, blue, red and purple can also be determined by the temperature of the color; Cold tone; Blue series, purple series, cool red series and cool green series are all combined in one picture.