Oil Painting for Beginners - Finishing
An oil painting must be properly cured before it can be varnished. This is because varnish will cut off the supply of Oxygen reaching the painting and it will take a lot longer to cure. Why Varnish?
The advantages: You do not have to varnish a painting but it will improve the finished look, as it will even up any variation in sheen across the painting. Also a painting that is varnished can be wiped clean with a damp cloth. Generally it provides a protective film and this film can be removed with Turpentine. (Very Carefully!!!)
The disadvantages: Cheap varnish is prone to yellow with age. Use a good one or not at all. I suggest Windsor Newton Artists Gloss Varnish or Matt Varnish. A semi Gloss Varnish can be achieved by mixing the two together. Bear in mind that gloss is dominant. Use more flat than gloss to achieve semi gloss. Varnish can by brushed on with a large brush. Lay it flat or it will run and ruin your painting. Spray varnish can also be used but should be also be done on the flat.