Directions Hang the sheet over a clothesline. Pour each color of tempera or poster paint into its own spray bottle, adding water until paint sprays easily (usually 50 percent water, 50 percent paint). Stand in front of the sheet and spray the paint in whatever design you want. If more than one person is participating, have each person take one color and spray together, creating a modern art overlapped effect. Let the sheet dry before taking it off the clothesline.