1. First, prepare red, black and white pigments. First, take a proper amount of red pigment and put it on the palette.

2. Then add the black pigment into the red pigment and stir it evenly, turning it into red and black. Then add the white pigment into the red and black pigments and stir well.

3. If you want to adjust the color to gray, first mix and stir red and green. If there is too much red or green, add another color and adjust it again until it appears gray.