Ingredients for varnish and varnish mediums definition

Finished oil paintings benefit from a protective layer to keep dirt, dust, and other material from damaging the work.  These varnish and varnish mediums can be bought commercially or made by the artist.  Common components of these protective layers are as follows:

Beeswax oil medium - 10 parts raw linseed oil, 2 parts beeswax, 1/16 part litharge. 

Beeswax medium - 1 part beeswax, 3 parts turpentine. 

Damar varnish - 1 part crushed damar resin, 4 parts turpentine.

Damar varnish medium - 9 parts damar varnish, 9 parts turpentine, 4 parts stand oil, 2 parts Venice turpentine.

Shellac varnish - 1 part shellac (clear or colored), 7 parts alcohol.

Stand oil medium - 1 part stand oil, 3 parts Venice turpentine.

Varnish medium - 1 part copal varnish, 1 part linseed oil, 1 part turpentine.