According to Lanzi, Antonio Contri discovered a valuable process, by
means of which he was enabled to transfer fresco paintings from walls to
canvass, without the least injury to the work, and thus preserved many
valuable paintings by the great masters, which obtained him wide
celebrity and profitable employment. For this purpose, he spread upon a
piece of canvass of the size of the painting to be transferred, a
composition of glue or bitumen, and placed it upon the picture. When
this was sufficiently dry, he beat the wall carefully with a mallet, cut
the plaster around it, and applied to the canvass a wooden frame, well
propped, to sustain it, and then, after a few days, cautiously removed
the canvass, which brought the painting with it; and having extended it
upon a smooth table he applied to the back of it another canvass
prepared with a more adhesive composition than the former. After a few
days, he examined the two pieces of canvass, detached the first by means
of warm water, which left the whole painting upon the second as it was
originally upon the wall.
Contri was born at Ferrara about 1660, and died in 1732. Palmaroli, an
Italian painter of the present century, rendered his name famous, and
conferred a great benefit on art by his skill in transferring to canvass
some of the frescos and other works of the great masters. In 1811 he
transferred the famous fresco of the Descent from the Cross by Daniello
da Volterra (erroneously said, as related above, to have been the first
effort of the kind), which gained him immense reputation. He was
employed to restore a great number of works at Rome, and in other
places. He was invited to Germany, where, among other works, he
transferred the Madonna di San Sisto, by Raffaelle, from the original
panel, which was worm-eaten and decayed, and thus preserved one of the
most famous works of that prince of painters. At the present time, this
art is practised with success in various European cities, particularly
in London and Paris.