This reduces the consistency and improves flow of Artisan oil colours. It also increases the gloss and transparency of Artisan. Artisan Water Mixable Linseed Oil is the main binder in the Artisan colours. When mixed with colour it reduces their consistency. Linseed oil is the most commonly used medium. It is combined with water or Thinner to maintain the structure of the paint film. It is also used when painting in layers to maintain the fat over lean rule - each successive layer must have more oil in it than the previous one.