S. And those who use gesso?,F. To use gesso, is to tempt fortune, for many old paintings are to be seen spoiled by the gesso, yet many are in good preservation, but this arises from the quality of the glue, which may be either too strong or too weak, but weak glue is best, because the strong absolutely spoils the canvas, whereas with the former very little gesso is required, for I have observed in the works of Bassano, that those pictures which have been primed with but little gesso are in good preservation, while those on which too much gesso has been used scale off; and you may distinguish these from the others by the texture of the canvas, the threads which are visible, although being painted they are covered with gesso, priming, and colours; while others which have smooth surfaces, from having too much gesso, scale off.,Besides the pictures on canvas, we have examples of this in old paintings on wood, which are well preserved in consequence of this practice of using glue. But dust also is very injurious to old pictures, as you will observe in those belonging to the nuns "Riformati", and Capuchins, whose pictures being kept free from the dust, the colours are preserved admirably. In order to avoid this difficulty, I use simple glue, as I have told you, when dry, that the canvas may become smooth. I afterwards give them the priming ground up with linseed oil. All earths are good for this purpose according to the taste of him who uses them. I use "terra da bocali", terra rossa, and a little umber finely powdered and mixed with linseed oil and stirred together for a short time, but not ground, over the fire.,I then spread this preparation over the canvas with a knife, and when dry and pumiced, I give the canvas another coat of the same colours, but these must be previously ground, and thus the canvas will be well primed; this is the best mode and the most certain in its results. I have also seen some persons steep the "terra da bocali" in water to soften, when it liquefies immediately; then, removing as much water as possible, the same quantity of linseed oil as of the water which remains behind is to be added; then the different ingredients are stirred together with a spatula until well incorporated. The priming is then applied to the canvas for the first time, but for the second coat the ingredients must be previously ground as I have before said. This method succeeds well and is quickly done, as little colour is required in the second coat, the canvas being already made smooth with the first. ,To the first coat made with earth distempered with water is added the oil which is pressed from the brushes when cleaning them, and which, being boiled with the sediment of the colours, dries like a mordant in the winter time; but umber is sufficient to make the second coat (which is ground) drying, and it does not require the boiled oil. This is the mode which I sometimes follow in preparing the canvas for my master, but the first mode which I mentioned is the best.,,