Generally speaking, there should be no more than three colors on a pyrograph, and attention should be paid to highlighting the main position of pyrograph in the whole picture. Chinese painting techniques can also be used to color boards. But care must be taken to prevent color from seeping out of the boundary. Because some Chinese painting pigments contain a lot of water when mixing colors, when such colors are painted on wooden boards, the pigments will seep out of the outline along the wood grain of the board, and the color of the oozing outline has penetrated deep into the wood grain, which is not easy to erase and will destroy the picture, which is a big taboo for pyrography coloring. Therefore, when coloring with this pigment, two measures should be taken: first, when dipping the pigment with a brush, it should be dried properly. Second, a little powder is infiltrated into this pigment to ensure that the pigment does not seep out of the contour line. After coloring, you should use a branding pen to complete the picture until it is perfect.

Spray high-quality colorless transparent varnish on the surface of clean pyrography works, so that the carbon particles formed by pyrography can be stabilized on the medium for a long time, and pyrography will never fade, which plays an effective protection role. Of course, the method of painting is particular. Because the varnish is sticky, it is not easy to be uniform with a brush, so the varnish should be covered on the pyrography by spraying. Generally speaking, it needs to be sprayed twice. The first painting is painted with primer. After painting, the varnish on the picture is dried and polished with fine sandpaper. Then spray varnish for the second time to make the whole picture clean and bright. For hot stamping with colored surface, spraying method should be adopted. If you use painting, it is easy to drag the colors out of the outline and it is difficult to clean them up.

There is a book called China Pyrography Techniques, written by Ai Xiuqi and published by Tianjin People's Fine Arts Publishing House. I suggest you buy one and have a look.