A wood finish refers to a layer, film or penetrant designed to enhance and/or protect the appearance or durability of wood surfaces. Finishes are usually either penetrating or surface types. Penetrating finishes infiltrate wood pores and fibers and generally provide a lower sheen than a surface finish. Most are oil based, the most common being Linseed or Tung oil.
Surface finishes leave a hard, protective film over the top of the wood. Generally applied with a brush, the most common types are lacquer, shellac, polyurethane and varnish.