from the wall, but the most successful method is the following: a canvas thickly spread with a strong adhesive is laid on the face of the fresco. When this substance has thoroughly dried the canvas is torn away from the wall and a surface varying from 1/16 inch to 1/4 inch is pulled off with the canvas. This is then levelled somewhat on the back and another canvas covered with mastic is very carefully laid over the back. When this has been put in place and has thoroughly dried the whole fresco is turned over and heat is applied to the front side to soften the glue. The canvas is then gently removed and the glue is wiped off. When the back canvas has been allowed to stay until the glue has thoroughly set it can be mounted upon a frame just like any ordinary picture. The curious thing about the process is that while the fresco appears on the canvas in almost as good preservation as when it was on the wall, the wall from which the fresco has been torn retains a shadow of the picture sometimes almost as clear as the original although, of course, uneven in surface. (A good example of this is the representation of St. Catherine, by Luini, in the Church of the Pelucca. The original is now in the Brera in Milan, while the wall of the chapel from which it was taken still shows a ghostly shadow of its former glory.)
