Retouching (sometimes also known as in-painting). Retouching should only be carried out to cover areas of damage in a painted surface. This will help to return the painting to a visually acceptable state. Great care is taken to restrict any retouching to the in-painting of local losses.

Accurate retouching is carried out using a stable medium that is different to the original. This medium should be non discolouring and it remains soluble in solvents. Retouching should always be easily reversible should it be necessary to remove it at any point in the future.