How do you spray paint a ceiling?

Canvas ceilings were almost universally covered with calcimine paint, a Whiting-based (chalk) paint with few binders. If you try to paint over calcimine paint with anything other than new calcimine paint you will have a mess on your hands, as the new paint will pull what is essentially chalk dust from the canvas. NEVER use latex or oil-based paint to recoat calcimine. To read up on calcimine paint, go to the following URL: google.com/search?client=safari&rls=en&q=calcimine+paint&ie=UTF-8&oe=UTF-8">http://www.google.com/search?client=safari&rls=en&q=calcimine+paint&ie=UTF-8&oe=UTF-8 Then go to the oldest paint store in your town and ask the oldest person employed there if the store still carries calcimine paint. (Young clerks won't have a clue.) Just be aware that when you add the weight of a gallon of paint to a canvas ceiling, the ceiling may sag in the middle from the added weight. It is therefore recommended that the old paint be removed first. To remove old calcimine paint from a canvas ceiling: Mix a pint of warm water with a few drops of dishwashing liquid in a new plastic spray bottle. Mist the ceiling a few square feet at a time. Waiting a few minutes, then use a large cooking spoon (one with no sharp edges) to gently remove some of the old paint as it loosens, starting at a crack in the paint if possible. This is a tedious job, but it must be done or the new paint will no adhere well to the canvas. Let the canvas dry thoroughly for several days before reapplying calcimine paint. One thin coat should do. Good luck!