This tip is for making a picture with chalk on paper. When finished, spray with cheap hairspray. The hairspray puts a fine coat of lacquer on the paper and you won't get chalk dust all over.
I also do chalking on Bisque. My grandchildren love to use chalk to color the pieces. It is less messy than paint when working with children. I have cans of both Gloss and Matte fininshing spray. Not all pieces need to have that shiny effect. They chalk Christmas ornaments and Easter ornaments. Chalk also works on Plaster of Paris.