I painted an old window with chalkboard paint and wrote on it with chalk paint pens. I did this as a decoration for our wedding and also our house.
First I taped around the window panr tape with Frog Tape (painted tape) this protect the old paint on the frame. Then I painted the window pane with black chalkboard paint.
Next I took the painter's tape off and touched up the window frame some. I sanded the spots that I wanted to look older.
Lastly I used chalk paint pens to write on the window! The chalk pens look much brighter and crisper than regular chalk.