PHOTO Louise Wijnberg
PHOTO Genevieve Silvester
water sensitivityWater sensitivity is a large topic with regard to unvarnished modern (oil) paints and cleaning. This phenomenon is not able to be identified visually, although there are visual indicators for water sensitivity. It is an important aspect for conservators, and often only identified after physical contact with the paint surface, such as during testing for surface dirt removal. This section of the website will contain links to research and current information on the causes of water sensitivity, up-to-date research in treatment methods for the removal of dirt from water sensitive paint and case-studies of paintings with water sensitivity.
Water sensitivity refers to the (negative) effect that aqueous solutions have on paint. It indicates that when an aqueous solution comes into contact with (oil) paint, the paint can swell or can be damaged/removed during physical contact with, for example, a wet swab. Water sensitivity is not visible per sé, however water sensitive paint often has what can be described as an oily, glossy film when viewed in daylight conditions. It is most often present on paintings from the 50's through to the 90's, although all periods since the 1900’s have paint films which are water sensitive. (Cooper et al. 2014) Some pigments are sensitive across all brands of paints, such as pure synthetic ultramarine blue, either due to the pigment itself or additives used in relation to its formulation (Mills et al. 2008, Tempest et al. 2013).