AIC's 44th Annual Meeting

In 2009 the Centre de conservation du Québec (CCQ) received a request for restoration of a photographic assemblage from the collection of the Colby-Curtis Museum in Stanstead, Quebec. The object consisted of twelve individual photographs mounted together in a wooden frame and included both daguerreotypes and ambrotypes. The brass mats of the individual photographs showed multiple corroded spots. Before undertaking the restoration, three methods of corrosion removal were studied: the Rosenberg method of galvanic corrosion of a sacrificial anode; local electrolysis; and localized application of an ion exchange resin - in this case Amberlite IR120 H. The three approaches will be discussed briefly in terms of effectiveness, rapidity of action, and controllability of the application system. The ion exchange resin approach was selected for use on the object at the CCQ. The resin (a polymer with acidic side groups), when placed in contact with metal oxides (or chlorides, or carbonates), cause these corrosion products to be reduced. The used exchange resin can be completely removed, leaving no chemical residue. Subsequent development of the method refined the technique for application of the resin and explored the use of mica powders for inpainting the treated areas. The ion exchange resin treatment method seems to be a promising approach to the treatment of brass mats from cased photographs; it should be further tested for its potential effects on the tinted shellac coatings and to discover its long term effects, if any.