Varnish for tempera
You can make tempera marble with lacquer or rose of Ghent and chalk. Once dry, glaze it with lacquer mixed with wine, for glue will dull and blacken it. And the whole will firstly appear red, but the varnish you will apply, which will penetrate it, will make dark and light parts appear as they should. The varnish is made like this: mix with clear Venice turpentine some aspic oil until it becomes clear and liquid, and this is done without fire. This is for things done in tempera, and the turpentine varnish that you know is for panel paintings. Pure lavender spike varnish is not good for panel paintings because lavender spike oil is too penetrating and makes colours shine unless it has been made long beforehand.