# Blushing (solvent blush)

Source: https://coatmentor.com/defects/blushing/ · Updated 2026-10-14

A milky, cloudy haze or pale, low-gloss spots on a drying film.

*Figure: Blushing (solvent blush): the surface as you see it, and a schematic cross-section.*

## Causes

- Fast solvent evaporation cools the wet film below the dew point, and moisture condenses in it.
- Spraying in humid air, or blowing air on the wet film.
- Fast-drying lacquers and other evaporative coatings are the most prone.

## Prevention

- Watch the dew point margin, and use slower thinners in humid conditions.
- Do not blow air onto a wet film.

## How it is assessed

Visual. It is a physical effect of moisture, unlike amine blush, which is a chemical reaction on epoxies.

## Telling it apart

- **[Amine blush](https://coatmentor.com/defects/amine-blush/):** Amine blush is a chemical product on the surface of amine-cured epoxies, greasy and water-soluble. Solvent blush is moisture trapped in the film of a fast-drying coating.
- **[Chalking](https://coatmentor.com/defects/chalking/):** Chalk forms over months of weathering and wipes off as powder. Blush forms while the film dries.

## Repair

Light blush may clear with a slower thinner. Otherwise abrade and recoat. The specification and the coating manufacturer have the final word on the repair procedure.

**16** practice items in the members area mention blushing (CIP 1: 7 · CIP 2: 5 · FROSIO written: 4).

## Related

- **Concepts:** [Dew point and the 3 °C margin](https://coatmentor.com/learn/dew-point/)
- **Standards:** [ISO 8502](https://coatmentor.com/standards/iso-8502/)

## About this page

Written from coating practice and the published rating standards, in our own words; the drawing is schematic. Checked on 2026-10-14; errors go in the [corrections log](https://coatmentor.com/method/). CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.