The whole process of watercolour restoration is a delicate balance between the stability of the painting and the handling of cleaning solvents. Based on experience, we determine not to overwork the cleaning process and risk losing the original image. The main objective is to eliminate discolouring from age and fungal staining, called foxing. There are proprietary cleaners which will irrevocably damage any painting on paper and so it is essential that tests are completed to establish the stability of the image and the quality of the paper on which it is set.
Since there are so many different grades [qualities] of paper it is necessary to be certain from the outset of any restoration of watercolours, how the paper will react to moisture and to the solvents which can readily remove stains.
The process requires a more careful and delicate approach than with an oil painting since any sudden loss of paint from the paper through the misuse of a solvent can ruin the original picture. The stains left by fungal deposits on paper known as ‘foxing’ can readily be removed with carefully mixed solvents but care must be taken at all stages of preparing the solvent so that the picture is not spoilt by replacing the brown stains with white bleach marks where the solvent has been too strongly mixed and then applied.
"The restoration of watercolours is essentially a slow, deliberate and painstaking process."