Alkali refined linseed oil is a pale oil extracted from the seeds of the flax plant. It is used in many of Michael Harding's paints because it produces the strongest paint film during the drying process and ensures the longevity of each painting.

When mixed with oil paint, linseed oil will increase the gloss and transparency of the paint, and will thin the paint so that it flows more easily and does not hold brushmarks. It will also slow the drying time of the paint. Linseed oil is also highly suitable for use with dry ground pigments.

Please note soft materials which have absorbed linseed oil should be stored in sealed containers, as the oil will oxidise when exposed to the air. This chemical reaction releases so much heat that the rags may spontaneously combust. Make sure the lid of the container is closed securely and store in a cool place. Brushes and tools used with linseed oil should be cleaned with white spirit.