1, according to my personal experience. It is best to use cooked rice paper for fingerprint painting. Ordinary lead drawing paper is not impossible, but it is certainly not so effective. You can imagine the effect of printing seal cutting on lead drawing paper and cooked rice paper. Fingerprint painting has a similar effect.

But the best effect is filter paper.

2, gouache pigment is not suitable because it is a little crowded, the colors are easy to blur and stick together, and the fingerprints can't come out. But you can try, the color is not strong or light-when it is "silky", it can still produce results if it is well controlled.

3, advertising paint is gouache! Don't you know?