What is used to prevent discoloring of the finish?

• A. Stain controller
• B. Primer
• C. Sealer
• D. Preservative

Answer: (A)

Preventing discoloration of the finish relies on blocking the substrate from affecting the topcoat. A sealer provides that barrier, sealing the surface so tannins, knots, or other underlying stains can’t migrate into the finish. By filling the pores and creating a uniform base, it helps the topcoat stay true to its color and appearance, reducing blotching or color shifts. Primer helps with adhesion and hiding the substrate, but its primary role isn’t specifically to prevent discoloration. Preservatives protect wood from decay or mold, not the color of the finish. Stain-control products exist, but the sealer is the standard choice for directly preventing finish discoloration.