Glossary: Paint Primer
**Paint Primer** is a preparatory coating applied to raw surfaces (like bare drywall, plaster, or raw wood) to seal the substrate, block stains, and ensure optimal adhesion and coverage yield of the topcoat paint.
Substrate Sealing & Adhesion
Using primer prevents the substrate from unevenly absorbing the binder in paint, which can cause dull spots or poor coverage rates. For metric applications, primer ensures the 8.59 m²/L paint yield is achieved on the first topcoat.