| the black oil, otherwise they will harden on the palette. They should be ground more fluidly than in the cases where raw oil is used. Ground in the black oil, they are both fluent and firm to the touch of the brush..
The black oil, by itself, has a soapy quality. It is extremely soft and it's tendency after being applied to the ground is to expand and run. The Italians found that by adding beeswax to it they could control this tendency, for tile beeswax served to cut and fix the oil. It seems to have performed the same function for the black oil as egg did for Van Eyck's boiled oil..
This addition of beeswax also serves another purpose it cuts down the glossiness of the colors and gives them a lightness and suppleness, like that of a mousse--such as we see in the Italian paintings of this period. The beeswax (prepared according to, the directions which are given on Page 178), is added to each of the colors, including the white. This wax is also, worked into some of the black oil and is used as a medium or diluent on the palette. The quantity of wax is always a question of the painter's preference. The heaviness of the impastos will be in direct proportion to the amount of wax in the paints. If the quantity used is excessive, the colors themselves will become waxy and too translucent and hard If this occurs, more oil or pigment can be added to them..
Canvases used by some of the Venetians seem to have been primed only with the coats of calcium carbonate, which we have described, and then to have had their absorption broken by one or more final layers of clear glue water. But many canvases have the lead and oil priming as well..
The essential condition for all of the canvases was the toned ground, some middle tone being used, red ochre, grayed with black or white or else simply gray..
The medium used to dilute the colors was the black oil mixed with beeswax or essence of turpentine. The black oil with the wax was supple and fluent and made possible a perfect blending of the colors, but for the highlights and the more precise accents in the drawing, essence of turpentine was probably used. It is unlikely that raw oil could have been used because it makes the colors too mat, and destroys their airy texture..
Note: for the variations in the technique of Titian and Tintoretto refer to chapter IX