What's the difference between a brush and a watercolor pen?

Watercolor pens are generally made of wool with strong water absorption, which is relatively soft to use. There are two kinds of pens: round and flat. Some round pens are very similar to the shape of a brush, and are mostly used for hooking and embellishing. Some are like brooms, which are suitable for laying music in a large area. Compared with the oil painting pen, the flat pen is not much different except the hair.

The brush head is round, and the diameter of the brush head is divided into large, medium, small, thin and extremely thin.

Oil painting pens usually have two kinds of tips, the most common one is bristles, which are relatively hard and suitable for drawing rough pictures. The other is made of chemical fiber, which is soft and suitable for drawing thin pictures. Most oil painting pens have no water absorption and are durable, so they need to adapt to repeated friction during painting. This is the biggest difference between oil painting pen and other brushes!