Primers are specially formulated paints that adhere to the wall and create a uniform surface for paint. By sealing pores, primers prevent stains from seeping through wood and can make a paint job last longer. Complete priming before painting unfinished surfaces and when switching between oil-based and latex paint layers.
Primers are available in three different formulas. Oil primers are slow drying and are best used on bare woods as they prevent raising the grain. Latex primers are fast drying and provide a more flexible finish than oil-based primers, making them a good choice for drywall. Shellac primers are used to spot prime-stubborn stains.