Conservation around the Millennium (Hungarian National Museum, 2001)
Pages - 55
PROCESS OF RESTORATION AND CONSERVATION Before cleaning, the first task is to preserve the inventory number marked on the bottom of the object and other data of documentary value. The inventory number was written in china ink on the bottom of the glass, then several layers of varnish were applied over it for protection. I did not apply any protection to the inventory number since the varnish did not seem to react to the materials I proposed to use for the treatment. CLEANING Mechanic cleaning First the dirt, which was loosely adhered to the surface, was mechanically removed from the glass. It could not penetrate the surface of the glass, but the cleaning effect of washing would have been rendered more difficult, and the object would have suffer an unnecessarily long chemical treatment. I used a scalpel to remove the remaining traces of adhesive from the fracture surfaces of the separated fragments. Cleaning with detergents Cleaning with detergents started with the separation of the still adhered fragments with soaking them in warm water. For surface active substance, fatty alcohol sulphate (anionic detergent) was used in a concentration of 0.2% on a temperature of about 40 °C. The surface active substance helps the penetration of the water between the fracture surfaces, decreases the adhesive capacity of the adhesive and the various fragments become easy to separate. The softened adhesive was mechanically removed from the surfaces. Soaking in the surface active agent also loosened the layers of dirt on the surfaces of the glass and they could be removed with a soft brush. Thick black markings could be seen beside the fractures on the inner surface of the glass, which could not be removed with the anionic detergent. I tried using another, non-ionic detergent (Prenol 10). Non-ionic detergents work within different conditions than anionic ones. Their critical micellar concentration is lower (0.05-0.5 g/l), the time needed for cleaning is shorter, they are more difficult to be washed off, and the temperature of the water cannot be higher than 30 °C. We found out during washing that the pattern on the surface of the glass was coated with the resin that was used as adhesive. The enamel paint became worn especially the black contours, so the missing details of the pattern were painted back on the surface and the whole was covered with resin. After cleaning with non-ionic detergent, the colours of the vessel appeared in an altogether different hue and the colours revived. The tulips became lilac, the flowers bright yellow and the background of the jug also turned into bright yellow. Cleaning was followed in both cases with thorough rinsing in water. Anionic detergents create a slightly alkaline medium. If the object stays longer in an alkaline environment, the stabilising and modifying substances of the material can be damaged. It had not been known that the object displayed data that refer to the origin of the glass vessel. It had been covered with thick fat atmospheric pollution. The 55
