FOR OIL PAINTINGS
Varnishes can be added during the course of painting or after it is completely dry in approximately six months time. See our lesson on Varnishing Your Work for more about how to protect your painting after it’s completely dry. Some artists use varnishes mixed with other mediums during the course of painting to create glossy, translucent glazing effects.
The first three varnishes on the list are the most common and the ones I use on my paintings.
Dammar: A natural resin made from a mixture of dammar gum and turpentine, it was originally sold as a picture varnish in 1826. The dammar gum is harvested from tropical lowland rainforest trees. Dammar varnish can be applied to a completely dry (minimum 6 months) oil painting as a final protective coat. Prevents dust from adhering to the painting surface and can be removed with solvents. Can also be mixed with other mediums (a popular mix is Dammar, turpentine and stand oil) and used during the painting process. Has a tendency to yellow and can become brittle and darken with time.
Retouch varnish: Used to give a wet look to an unfinished, dry painting before work is resumed. It unifies the painting surface and can bring back “dead” or “flat” areas where the medium has become matte.
Gamvar: A type of picture varnish created by Gamblin, it improves colors, unifies the surface, and protects the painting from damage. Here’s a video about using Gamvar from Gamblin Artists Colors: http://vimeo.com/91544967
Copal: Another resin tapped from trees, it increases flow and gloss of oil paint, but like dammar it yellows and darkens with age. Not to be used during the painting process or in the grounds (acrylic gesso or oil grounds). Copal medium is also very susceptible to cracking, especially in cold weather.
Mastic: A resin derived from the sap of the Pistacia lentiscus tree, it is less glossy than other resin varnishes and imparts a semi-gloss finish and increases color luminosity. It does have a tendency to bloom (make milky white circles) and also darkens to brownish yellow or greenish brown with age.
Picture varnish: A final varnish that can be purchased in matte, gloss, or semi-gloss.
Mixing varnish: As an ingredient in painting or glaze mediums intended to be added to tube colors for various techniques of oil painting.
Isolating varnish: A solution of a resin that is insoluble in turpentine and mineral spirits, used as an isolation coat between layers of paint. Isolating varnish can be applied directly to the canvas without the inclusion of paint to create depth and brilliance. Some are made with mastic, so be aware of the possibility of yellowing.
Download and print our Traditional Oils Recommendation List here.