Oils are very important for oil painters
Oil painting would not be what it is without oils! There are different varieties of oils available out there. It is important to learn which are best for your own painting practice.
The natural oils used in oil painting are obtained from seeds and nuts they are referred to as vegetable oils. Only drying and semidrying oils are commonly used in painting. There are of course oils that exist that never dry. You will never want to use these of course as you want your painting to dry eventually!
The main varieties of oils available to painters are linseed oil (a drying oil), safflower, sunflower, and poppy seed oil (all semidrying oils). Linseed oil can sometimes have a tendency to yellow over time. Whereas safflower, sunflower and poppy seed oil have less tendency to yellow. Linseed oil is the quickest drying over time in comparison to the long drying times of the rest.
All of these oils mentioned do not dry via evaporation. Rather, they dry by absorbing oxygen and forming solid forms. Once dried, they cannot return to liquid form.
These oils serve three purposes for your painting:
- They act like a glue binding the pigment to the ground.
- Oils help to bring out greater depth in the color
- Help protect the pigment for years to come by binding them in an enveloping film.
So, now a little bit about each oil and its pluses and minuses..
Linseed oil is essentially the same as the flaxseed oil you will come across at your grocery store. However, it is not edible! The extraction method used to make artist’s linseed oil uses petroleum – not something you would want to consume ;-). This oil is one of the most popular used by painters due to it creates very stable paint. There are essentially two different varieties of linseed oil – cold pressed and refined.
Cold pressed oil does not undergo any chemical treatment so is considered one of the more stable oils out of the two. However, it as more impurities in it compared to refined linseed oil – as can be noticed in its coloring.
Refined Linseed Oil
Refined linseed oil is less likely to have impurities in it. Therefore, it is less likely to yellow over time. In general people look for the oil that has the least impurities in it – these will look clearest in the bottle. Compare the images of above of the refined (appears first) to the cold pressed – as you will notice the refined oil is clearer.
Poppy oil is very pale and transparent. It is less likely to yellow over time in comparison to linseed oil. If you do not want your painting to dry quickly this is could be a good option for you! Drying time takes about 5 – 7 days on average. Those who like to work wet in wet will love poppy oil!
Walnut oil has been used to make paint for a long time – longer than linseed oil. Like poppy oil, walnut oil yellows less than linseed oil. When dry, the film of Walnut oil is stronger than poppy oil. However, linseed oil is still stronger than both. Walnut oil has a silky texture to it with a similar drying time to poppy oil. However, the big downside to walnut oil is that it must be used when fresh. If not, it goes rancid quite quickly. You probably do not want to have a smelly painting hanging at a gallery 😉
Safflower oil is used in some brands to make whites as it also has less tendency to yellow over time. Like poppy seed oil, its drying time is longer than linseed oil.
Sunflower oil is less yellowing with a slower drying time compared to linseed oil. As a lesser used oil this oil type is much more difficult to find compared to the other oils mentioned!