What are drying and semi-drying oils in oil painting?

Drying and semi-drying oils are the vegetable oils used to make oil colour: linseed, poppy and safflower. The different methods of processing oils produce products with different drying rates, consistencies and colour.

Oils are used to modify the consistency, gloss and drying time of colour. Using oils can prevent over-thinning, which may happen when using solvents. They are also particularly useful in maintaining flexibility of paint films, especially when working fat over lean.

How do the types of linseed oil differ?

Cold Pressed Linseed Oil will dry slightly quicker than Refined Linseed Oil and may have better flow with some colours. Stand Oil is paler and thicker than refined and is the slowest drying linseed oil. Drying Linseed Oil is the fastest drying linseed oil.

How do poppy and safflower oil differ from traditional linseed oil as mediums?

Poppy and safflower are classed as semi-drying oils, while linseed is a drying oil. Semi-drying oils are paler than linseed but dry more slowly. Poppy oil is supplied as Drying Poppy Oil, which has driers added to it. This provides a pale medium for use with whites and blues, but with a comparable drying rate to linseed to help avoid cracking.

What is the best equivalent to the discontinued Bleached Linseed Oil?

Drying Poppy Oil has the same properties as Bleached Linseed Oil. It is quick drying and its pale colour makes it suitable for whites and pale colours. It is also effective in increasing the gloss and transparency of oil colours and is non-yellowing.