The ancients used ink ingots to make books. When choosing ink, the first thing to look at is whether the ink quality is delicate and moist. Good ink is thin and hard, fragrant, and bad ink is thick and loose, with a bad smell. Secondly, it depends on the color of the ink. Black and purple are the best, followed by pure black, cyan and gray. Third, listen to the sound. The sound of good ink is heavy, the knock is loud and crisp, the sound of bad ink is light, and the knock is small and dull. The quality of ink directly affects the effect of books. No matter whether the nib is soft or hard, good ink can make the pen smooth, rotate flexibly, and be non-sticky, non-astringent, non-stagnant, non-flying and non-scattering. Therefore, calligraphers of all ages attached great importance to the choice of pen and ink. Although grinding ink is good, it is more troublesome. It is more convenient for calligraphers now, but it can't meet the present situation and should be improved.