Paint flashing is an uneven appearance of a paint coating's gloss, sheen or luster.

It can occur as a result of any one of the following reasons:

• Use of a gloss alkyd/oil-based paint or solvent-based epoxy in areas of direct sunlight
• Exposure to moisture or condensation while drying
• Temperature fluctuations during drying
• Coating over a porous surface
• Paint applied at uneven film thickness (i.e. lapping)
• Insufficient film build (e.g. coating applied too thin)

Paint flashing isn't normally a major challenge, but can still create hurdles in achieving the goals of a design project.

There are several potential solutions for fixing paint sheen, depending on the cause:

• Exterior alkyd/oil-based paints and solvent-based epoxies can develop a chalky appearance. Washing the chalk off should return most of the original finish, but it can chalk again. To avoid this, recoat with an acrylic and follow all label directions.
• Prime or seal surfaces before applying the topcoat to ensure a uniform surface.
• Spot-prime any patched areas to level off the porosity of the surface.
• Apply an additional coat to even out sheen irregularities.
• Thin any touch-up coating to help it blend in better.
• Follow label and data page directions for all products used.

Be sure to see our lead information page for tips on staying safe during restoration projects requiring preparation prior to paint application.