How to Choose a Paint Primer

Prime new drywall with a polyvinyl acetate primer especially for new drywall. A PVA primer saves you money -- the first coat on new drywall really soaks into the surface, and drywall primer is cheap. Priming the drywall first also ensures a more durable and washable finished surface.

Skip the priming on composite wood trim and of course pre-primed trim. You don't really have to prime new wood either, although it may save you some time. Wood primers do not "raise the grain" of wood as much as water-based paint will, and you'll have to sand a little more thoroughly in between the first and second coats.

Apply an oil or shellac primer to redwood or cedar, no exceptions. These woods contain tannin, which will bleed yellow and brown stains right through any water-based paint.

Prime exterior wood trim and siding with either a good acrylic or an oil-based primer for best finish.

Clean galvanized metal (like gutters) and aluminum and paint, without a primer layer. Iron and steel usually must be primed with a rust-inhibiting primer before painting.

Paint white or light colors directly over dark or intense color walls: no primer necessary. Since most primers aren't designed to hide underlying colors well, most likely you'll just be adding an unnecessary coat of paint to your job.

Apply a tinted primer when going from a light color to a deep color, like red. Check with the paint store when buying the paint on other colors. Most colors will only require two coats of paint -- no primer necessary. Some colors in "neutral" or "accent" bases, like some reds, require a colored primer or you'll be doing up to six coats of paint!