All painted works  should be coated with varnish. Varnish not only aids in preservation of the work, but also improves its appearance by providing an even gloss, saturating the colours, and to protecting the paint. It protects from abrasion, atmospheric pollutants, and ultraviolet radiation.

The varnishes used can be matte or glossy, and depend on the period and subject of the work.

Varnishes are applied either by brush or spray.