Blushing

Blushing is the name given to a phenomenon where, after polishing, the paintwork becomes cloudy. This is caused by evaporation of solvents within the paint. It is best avoided by not polishing cars that have been recently repainted. If it occurs, it can be removed by waiting another month and trying again.

What it means

Blushing is a paint defect that shows as pale, milky or cloudy patches in fresh paint or clearcoat. Instead of drying clear, the finish looks as if a light white fog has been trapped inside it. This usually happens when the solvent evaporates very quickly and chills the surface, causing moisture from humid air to condense into the paint film. It is most often seen in cellulose and 2K systems sprayed in poor conditions, or when the wrong thinners are used for the booth temperature.

Why it matters

• Ruins clarity and depth: Even if the panel is dust free and smooth, blushing kills the gloss and clarity, so the colour looks washed out and cheap.
• Can signal wider process problems: Blush is a clue that temperature, humidity, air movement or solvent choice is wrong, which can affect other parts of the job too.
• Often needs rework: Mild blushing can sometimes be improved with controlled warming or a light overcoat, but heavier defects usually mean flat and polish or full respray of the affected area.

Where you’ll see it

You will see blushing mentioned on bodyshop rectification sheets and technical bulletins, often described as milky clearcoat, moisture blush or whitening in the lacquer. It tends to show up on larger panels such as bonnets, roofs and doors, and can be easier to spot on darker colours where the milky cast contrasts with the base colour underneath.

Context

Blushing sits in the family of paint defects caused by application conditions, alongside solvent pop, die back and loss of gloss. While solvent pop is about trapped solvent gassing out and leaving pinholes, blushing is specifically about moisture being trapped in the film or poor solvent balance causing the lacquer to lose clarity. Prevention usually comes down to controlling booth temperature and humidity, choosing the correct thinner or reducer and avoiding very fast products in cold, damp air.

Common mistakes

• Spraying with fast thinners or reducers in cold, damp conditions and being surprised when a milky blush appears as the paint flashes off.
• Trying to polish blushing out of a still-contaminated or moisture filled film instead of addressing the root cause with correct application and, if needed, repaint.
• Ignoring booth humidity, gun distance and overlap patterns, which can all contribute to uneven build and localised blushing.
• Continuing to pile on more coats over a blushed area in the hope it will disappear, which often makes the cloudiness worse and adds to the amount of material that later needs to be removed.

Written by Danny Argent. Last updated 19/11/2025 15:39