EVALUATION OF THE EFFECTS OF ENVIRONMENTAL-CONDITIONS AND PREVENTIVE CONSERVATION TREATMENT ON PAINTING CANVASES

The use of preventive conservation measures to assist in retarding the deterioration of painting canvases has been suggested by the Conserva tion Department of the Tate Gallery [S. Hackney and T. Ernst, The appl icability of alkaline reserves to painting canvases, in Preventive Con servation Practice, Theory and Research, Pre-prints of the contributio ns to the Ottawa Congress, 12-16 September 1994, Ottawa, Canada, p. 22 3-227]. The reverse sides of paintings are treated with commercially a vailable methoxy magnesium methyl carbonate (MMC) solution. The aim of this paper is to describe how dynamic mechanical thermal analysis can be used to evaluate the effects of this treatment. Measurements are d escribed on modem commercially primed canvas samples [N. Wyplosz, S. H ackney and J.H. Townsend, Studies on the deacidification of canvas wit h methoxy magnesium carbonate (MMC), in pre-prints of the European Com mission research workshop ''Effects of the Environment on Indoor Cultu ral Property'', p. 30.] which show that the MMC treatment does affect the mechanical properties of the treated canvas samples and that dynam ic mechanical thermal analysis (DMTA) is a suitable technique for its evaluation. The treatment appears to produce a coating an the samples which acts as a moisture barrier. This was also found to occur for tre ated historic samples (Battelle process) from loose-lining canvases re moved from 19th century paintings. The response of the MMC treated mat erials to variations in relative humidity has also been studied and in dications are that their response to variations in relative humidity d iffers from those of the untreated canvases. (C) 1997 Elsevier Science B.V.