Linseed oil

From Principles of Applied Arts

Linseed oil is a yellowish drying oil derived from the dried ripe seeds of the flax plant (Linum usitatissimum, Linaceae). It is obtained by pressing, followed by an optional stage of solvent extraction. Cold-pressed oil obtained without solvent extraction is marketed as flaxseed oil. It is suitable for human consumption (though not recommended for cooking) and is used as a nutritional supplement which is high in omega-3 fatty acids, especially alpha linolenic acid, and relatively low in omega-6 fatty acids, allowing it to be used to lower the ratio of omega-6 to omega-3 oils in the diet, which may have health benefits. Boiled linseed oil was used as a paint binder or as a wood finish on its own. Heating the oil makes it polymerize or oxidise more readily. However, today, metallic dryers are used instead of heat. The use of metallic dryers makes boiled linseed oil inedible.