Oils for oil painting

Bleached linseed oil differs from purified linseed oil only in terms of colour. As the colour of linseed oil is affected by conditions (light, oxidation), the difference in colour between the two oils will largely disappear over time.

Because, over time, linseed oil shows a certain degree of yellowing, linseed oil is sometimes replaced by safflower oil, particularly for white paint. Safflower oil is pressed from the seeds of the safflower thistle. This oil yellows less than linseed oil, but the drying time is longer and the oil forms a paint film with different properties than linseed oil.

The use of white based on safflower oil in a layered structure of a painting, where it forms a substrate for colours based on linseed oil, can cause phenomena such as crackle or even detachment of layers of paint above. It is therefore advisable to limit the use of white paint based on safflower oil to the final phase of the painting.

Stand oil is a very fat oil and is consequently particularly suited for the final layers.
It is obtained by heating linseed oil without the addition of oxygen. No oxidation occurs. The oil becomes thicker as the molecules group together (polymerisation).

The honey-thick stand oil can be thinned with white spirit or turpentine and forms a more flexible film than standard linseed oil. In the past stand oil was used as a glazing medium, but these days it is used mainly as an ingredient in making one's own medium. It is a very fat oil and is consequently particularly suited for the final layers. The chance of the paint wrinkling is less than with linseed oil, and the drying time is increased, as is the gloss.

Boiled linseed oil is a linseed oil heated with siccatives that can be used in a self-made medium for oil colours to allow the paint to dry faster. The term "boiled" is not exactly correct, as the oil is heated to below the boiling point. This is done with the addition of siccatives and so the oil can be used as an ingredient to make a quick-drying painting medium. When using boiled linseed oil, pure or as an ingredient of a self-made medium, siccatives may not be added in connection with the durability of the paint film.

Compared to linseed oil, poppy oil dries slower, is paler, yellows less and is less likely to scorch the paint. Because of these properties, a homemade medium based on poppy oil can be used in combination with light colours in the "alla prima" technique. However, poppy oil forms a weaker film than linseed oil and, when used in the lower layers, can cause problems for the adhesion of linseed oil paint in subsequent paint layers. It is therefore recommended to use poppy oil only in the last layer when layered painting.

Linseed oil has proven itself over the centuries as a binder with the best combination of properties. Because, over time, linseed oil shows a certain degree of yellowing, linseed oil is sometimes replaced by safflower oil, particularly for white paint.

This oil yellows less, but also has disadvantages: the drying time is longer. Safflower oil is, therefore, not suitable for pasty use and in undercoats. White based on safflower oil is used mostly in the top layer.