A clear coat of varnish on an oil painting is the final step in the creation of a lasting work of art.
Varnish may be thought of as the final layer of paint in an oil painting. It is important for two reasons. First, a properly applied varnish layer will even out the variations of gloss in different shades of oil paint, lending a uniform luminance to the finish. Second, varnish is a necessary protectant against dust and atmospheric contaminants that begin to degrade the surface of an oil painting almost as soon as the paint dries. The most important attributes of an oil paint varnish are superior clarity, favorable removability properties for later restoration and easy application.
Instructions
1. Allow a minimum of six months for an oil painting to dry before applying varnish. Test to see if the oils have cured completely by dipping a lint-free rag into a solvent, such as white spirits, and gently rubbing it across the surface of the painting. If no color transfers to the rag, the oil painting is dry.
2. Select a 1-inch to 4-inch flat, soft, tightly packed brush specifically designed for varnishing.
3. Lay the painting on a flat work surface. Do not varnish vertically.
4. Apply the varnish in a succession of thin coats. Thick coats may cloud and/or reveal brush strokes.
5. Avoid fast or sharp brush strokes during application. Thin varnish may bubble if brushed too energetically. Inspect the surface from different angles as you varnish to detect bubbles. Brush them out as soon as they are detected.
6. Use long even strokes, covering the painting from top to bottom while advancing from side to side.
7. Avoid brushing over completed areas that have begun to dry. Applying fresh varnish over varnish that is curing will cause clouding. If you notice any missed areas, allow the varnish on the remainder of the painting to cure completely before touching up.
8. Place the oil painting under a tent of plastic film after varnishing to avoid attracting dust while the varnish cures.
