# Bleeding

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

Stains or a colour change in a new top coat, as patches, halos or an overall shift, where colour moved up from below.

*Figure: Bleeding: the surface as you see it, and a schematic cross-section.*

## Causes

- Solvent in the new coat dissolves a coloured coat below.
- Coal tar or bitumen under an ordinary top coat.
- Some red organic pigments under a light top coat.
- A strong solvent in the new coat over an old coating of unknown type.

## Prevention

- Seal a bleeding coat with a barrier coat, for example an aluminium-pigmented sealer, before the top coat.

## How it is assessed

Visual. Another coat of the same top coat does not cure it: the colour comes back.

## Telling it apart

- **[Fading and discoloration](https://coatmentor.com/defects/fading/):** Fading is paler colour from sunlight. Bleeding is a foreign colour coming up from below, often soon after the new coat.
- **[Contamination and inclusions](https://coatmentor.com/defects/contamination/):** Stains from outside, such as rust run-off, sit on the surface and often wash off. Bleeding stains are inside the new film.

## Repair

Apply a suitable sealer or barrier coat, then the top coat. The specification and the coating manufacturer have the final word on the repair procedure.

**2** practice items in the members area mention bleeding (CIP 2: 1 · FROSIO written: 1).

## Related

- **Concepts:** [Protective coating types](https://coatmentor.com/learn/coating-types/)
- **Standards:** [SSPC-PA 1](https://coatmentor.com/standards/sspc-pa-1/)

## 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.