Of Painting in Oil on Canvas.
§ 88. _Painting on Canvas._[218]
In order to be able to convey pictures from one place to another men
have invented the convenient method of painting on canvas, which is of
little weight, and when rolled up is easy to transport. Unless these
canvases intended for oil painting are to remain stationary, they are
not covered with gesso, which would interfere with their flexibility,
seeing that the gesso would crack if they were rolled up. A paste
however is made of flour and walnut oil with two or three measures[219]
of white lead put into it, and after the canvas has been covered from
one side to the other with three or four coats of smooth size, this
paste is spread on by means of a knife, and all the holes come to be
filled up by the hand of the artist. That done, he gives it one or two
more coats of soft size and then the composition or priming. In order to
paint on it afterwards he follows the same method as has been described
above for the other processes. Because painting on canvas has seemed
easy and convenient it has been adopted not only for small pictures that
can be carried about, but also for altar pieces and other important
compositions, such as are seen in the halls of the palace of San Marco
at Venice,[220] and elsewhere. Consequently, where the panels are not
sufficiently large they are replaced by canvases on account of the size
and convenience of the latter.[221]