Crude linseed oil is extremely penetrative and impregnating. It also takes longer to dry. Boiled linseed oil dries faster and penetrates well into the substrate, but not as deeply as crude linseed oil. We use boiled linseed oil as a binder in our linseed oil paints. Crude linseed oil is most often used in connection with priming outdoors. The most common linseed oil you may come across in the trade is instead hot-pressed linseed oil. We advise you not to use it because hot pressed oil is of poorer quality. If it is not clear on the packaging that it is cold-pressed, it is usually a hot-pressed linseed oil.