Conservation around the Millennium (Hungarian National Museum, 2001)

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1. Agostino Barbarigo Doge hands over a banner (condition on receipt)

Similar black layers could be observed at the restoration of other detached frescoes. In one case, investigations were made in Germany on the occasion of a thesis work for the Restorer Training Institute in 1993.1 Nevertheless, this study raised more questions than it could answer. The investigated black glue layer had been especially sensitive to water, while the one we dealt with was not. The main problem is that the investigations demonstrated animal glue, which is at least queer. It explains why it is soluble in water but raises other problems. Namely, this glue should theoretically not be soluble in water! Frescoes were usually torn off the wall with glued canvas stuck to the painted surface. This canvas, the so called “facing" has to be removed from the surface of the fresco in warm water before applying it to the new support of the painting. It means that the new support must be stuck to the backside with a substance that remains stable in hot water.

Bleached shellac could be used for pulling down the painting from a moist wall. In this case animal glue is justified for glueing it to the new support, since the “facing" was removed with alcohol. It is also interesting to observe that several of the earlier used glue layers are sensitive to water, which does not have a logical explanation. (The use of shellac is rather exceptional!)

The main bulk of the glue on the Romanino paintings contained calcium- carbonate according to the analyses made thus far. When it had been removed, a substance of protein character was demonstrated. This result resembles very much the traditional Italian glue, which is composed of lime, white cheese and linseed oil. The materials prepared more than a hundred and fifty years ago secured the survival of the paintings, they have stayed stabile and even porous,

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