You can draw a harder point on the blackboard with chalk dipped in water. At this time, there is a trick: for example, in a calligraphy, the solid part inside can use white dots. Before the white one is dry, you can use the pink one as the ditch edge, so that the pink can penetrate into the white one a little bit, which is very beautiful.

In addition, gouache pigment can also be used, but it is recommended to use the large bottle for blackboard newspaper, which will make the color matching more convenient.

If you want to be different, you can cut the pleated paper into ribbons, then fold it and stick it on the blackboard as a border, which will have a three-dimensional effect. Of course, the person who does it must have certain skills.

There are also cans that can be used to spray colored solids at weddings. I can't say what it is at once. This can be equated with painting.

That's all I can think of