Painting with Linseed Oil: What you need to know

In this article with details, information, images and FAQ’s, we will give you a behind the scenes look into the foundation of oil paint, Linseed oil.
Written by: Mot Tuman

What is Linseed Oil?

Created from Flax seeds, Linseed oil defines the features of an oil paint. It works as a binder, holding the pigments together, as well as a medium. Adding more Linseed oil can create fattier, more transparent paint layers as well as slow down the drying time of oil paint.

Linseed oil, as well as the other oils used in oil paints, is known as a drying oil.

Drying oils are exactly as their name describes; they dry over time. This is unlike well known non-drying oils that you can often find in your kitchen, such as olive oil or canola oil. Drying oils have a slight difference in their molecular make-up that allows them to fully cure, even if it might take 6 months or more to do so.

This is what makes oil paints distinct from other mediums, such as oil pastels. While oil paints will become touch dry and eventually cure, oil pastels will never fully dry. Though there are several different drying oils that can be found in oil paints, Linseed oil is the most popular for several reasons. 

Why Use Linseed Oil?

Linseed has the strongest film of any other oil used, making it less likely to crack. It also dries relatively fast for an oil, becoming touch dry in a few days and curing fully in about 6 months. Unfortunately, Linseed also tends to have a pale yellow color. This makes it unideal for pale hues of paint, such as white, because oils tend to yellow over time. 

Because of this, you may find some other drying oils in your paints such as Poppy or Safflower oil. Both of these are pale, better suiting them to white paints, despite the fact that they have a weaker paint film and dry at a slower rate. 

There are also paint manufacturers that may combine drying oils, such as Poppy and Linseed, to gain mixed attributes. This could give a paint less of the yellowing that comes with Linseed while still having some of the strength that Poppy lacks. 

Types of Linseed Oil

You may come into contact with slightly different types of Linseed oil available on the market. While any type of Linseed oil should accomplish similar tasks in your oil painting, here are some of the different labels you will encounter on the market and what they mean: 

Refined Linseed oil is the most common type of Linseed on the market. It is different from raw Linseed in that it has been processed to have a low level of acidity and will dry faster than unprocessed, raw linseed oil. 
For oil paint made with refined linseed oil binder: Tusc & Pine Artists’ Oils

Cold pressed Linseed oil is oil that has been extracted from flax seeds without the use of heat. It creates an oil without impurities that may dry slightly faster than typical Refined Linseed oils.  

Linseed Stand Oil is slightly paler and thicker than other types of Linseed oil. 

Water-Mixable Linseed Oil, also known as water-soluble Linseed oil, is Linseed that has been modified chemically to be soluble with water. While it is specifically made for use with water-soluble oil paints, it can be combined with traditional oil paints. Traditional oil paints will become slightly water-soluble when enough water-mixable Linseed is added in. 

How to Use Linseed Oil

Linseed oil is traditionally used as a medium to add fat content into oil paint. Following the fat over lean rule, the more layers of paint that are added to a canvas, the fattier each layer needs to be in order to have the right adhesion necessary to keep the painting from cracking. 

An artist can achieve this extra fat content by increasing the amount of oil added into each layer of paint. The more Linseed oil, the thinner and more transparent the paint. 

Fat Over Lean 

This rule of fat over lean is important when an artist is painting over the course of several days, weeks, or even months, with each layer of paint beginning to cure before the next one is applied. When it comes to painting alla prima, or all in one sitting, fat over lean should still be followed to some extent, but the linseed oil will mix and infuse with other wet areas of paint on the canvas since they have not cured yet, making issues with adhesion and curing less of a problem. 

How Much is Too Much?

However it is important to not use too much Linseed oil. An excess amount of linseed oil can cause paint to wrinkle and loose adhesion, particularly if it is applied in thick or impasto styles. 

The exact amount of Linseed you should use varies depending on the pigment and oil content of the brand of oil paint, but a good rule of thumb is to make sure your mixture never exceeds a runny sour cream consistency. Ideally, the biggest difference in ratio of oil to paint content should be applied as final layers, such as with a glaze. 

Going Beyond The Medium

Besides adding it in as a medium, linseed oil can also be used as a binder to create your own oil paint. For an in-depth tutorial on crafting oil paint check out this video: https://www.youtube.com/live/F0as669X1us?si=4qX0wJym531bC586

Frequently Asked Questions (Q&A)

What is Linseed Oil Used For?

A: Linseed oil is typically used as a binder and medium for oil paint. It can bind together pigments to give oil paint its unique attributes as well as add in additional fat content. It is also known for increasing a paint’s transparency and slowing dry time

Is Linseed Oil Toxic?

Linseed oil is considered non-toxic when used for its described purpose. Ingesting Linseed oil is not recommended. 

Should I use Linseed oil before painting?

It is not recommended to use Linseed oil on a canvas before painting because it will add fat content that can mess with subsequent layers’ adhesion. Instead, start out with a thin layer of paint created with a medium meant to reduce fat content, such as turpentine, and slowly increase the amount of fat content in subsequent layers, as per the fat over lean rule. 

What are the disadvantages to Linseed oil?

Linseed, while it is a go-to for many artists and paint manufacturers, does have the tendency to yellow more than some other oils, such as Poppy or Safflower. However, its durability and drying time are the best out of any other oil, making it the most popular.