This surface cleaning  project, organized by the Courtauld Institute of Art and the Instituut Collectie Nederland, aimed to define guidelines for the use of various materials for surface cleaning unvarnished paintings. The following cleaning agents were tested on three 20th-century oil paintings: saliva, an ammonium hydroxide solution (pH 8–8.5), triammonium citrate (TAC) and sodium tripolyphosphate (STPP). The chelating agents were used at a range of concentrations, and preliminary tests were performed at a range of pH. The surface topography of the paint before and after cleaning was examined using scanning electron microscopy (SEM). Swabs used to apply the cleaning agents were analysed with SEM/EDX to determine what type of material was removed during cleaning. An attempt was made to detect citrate residues using gas chromatography/mass spectrometry (GC-MS).


A more extensive investigation into surface cleaning unvarnished paintings has been published as:

Rachel Morrison, Abigail Bagley-Young, Aviva Burnstock, Klaas Jan van den Berg and Henk van Keulen (2007)

β€œAn investigation of parameters for the use of citrate solutions for surface cleaning unvarnished paintings,”

Studies in Conservation, Vol. 52, No. 4, pp. 225-270.


Surface cleaning unvarnished paintings

The effect of selected materials used for

Dr. Abbie Vandivere, accredited painting conservator based in the Netherlands