Preparation:
Make sure the paint is thoroughly dry; with thin to normal layer thickness, this takes about a year, with thicker layers several years.
If a painting is to be varnished that is already several years old, the surface of the painting can first be wiped with a cloth to which some white spirit has been applied. This removes the dirt from the canvas and opens the paint skin slightly. The varnish will then adhere better.
Steps in varnishing:
• Matt and satin varnishes contain matting agents that sag in the varnish and should therefore be shaken well before use; this is to avoid gloss differences.
• Make sure that both the painting and the varnish are at room temperature.
• It is a good idea to lay the painting flat (generously on a piece of cardboard, plastic or newspaper).
• Hold the spray can horizontally (do not point downwards) and spray forward so that a mist of varnish descends on the painting.