Isn't it standard practice to use linseed oil as a primer / base coat before putting the real paint on? There's an amusing article about the Steinway Piano company in the NY Times where they talk about the process of making pianos. Quoth the article:

Soon a worker, Jeremy Shepherd, was sponging linseed oil on the rim. "You've got to fill the pores," Mr. Senia said. "That's important, so the lacquer doesn't go in and damage the wood. This way, you know you'll have a smooth finish."