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How to Thin Oil Paint

how to thin oil paint

Painting with oil paint can be difficult because it’s so thick and hard to work with, especially for rookie artists. You may have already tried thinning the paint yourself, but you’ve found that this doesn’t always work how you want it.

Indeed, artists utilize different methods and tools to thin their paint. Let’s look at how we can get better results when working with oil paints!

The first step is to understand how the paint behaves when it’s thinned. The oil paint will start to dry very quickly, so you’ll need to work fast.

You may also find that the color changes slightly when it’s diluted, so be prepared for this and adjust your painting accordingly. Read on!

How To Thin Oil Paint With Medium?

The best way to thin oil paint is with a medium. This will help the paint flow more easily and give you better results. A medium of your choice can be bought at an art supply store or online. You just need to add a small amount of the oil to your paint and mix well.

There are many different types of mediums available, so how do you know which one to use?

Some mediums have been made specifically for use with certain oil paintings. They are more effective than others because they balance out how thick or thin your paint is already.

Not all types of oil paint are compatible with the same medium. So, before purchasing a medium for your paints, make sure that it’s made specifically for them.

Medium Type 1: Oils

One way to thin oil paint is to add some oils,

Slow-Drying Oil:

  • Linseed oil – This type of oil takes around five days to dry, which is considered slow. You should also know that it can turn yellowish after a while, thus not the best choice for thinning light and cool tone colors
  • Stand oil – Stand oil texture is the same as linseed oil. Still, it is better in terms of retention of the original color since it is pretty thick
  • Walnut oil – Another slow-drying medium for thinning oil paints is walnut oil. You can use this medium to make your paintings look more vivid and intense. Furthermore, it resists yellowing through time quite well, better than linseed and stand oil

Very Slow-Drying Oils

  • Poppy oil – This type of oil really takes its time to dry completely. Therefore, people use it when they want to slow down the drying process. The weak point of this oil must be stability
  • Safflower oil – During its long drying period, this oil creates a sticky feeling. So, do not panic if it appears to be different from other types of oil. The good thing is safflower oil is not prone to extreme and quick yellowing

All of these oil mediums produce a glossy finish for your paintings.

These oils will make the mixture less viscous and easier for you to work with. Still, how the painting appears in its final form may change slightly depending on how much was added (the color can become weaker).

Important Notes:

  • You should be careful when using these because too much of them usually leads to a sticky mess that’s difficult to clean off
  • Although it might seem easy at first glance, working with thinner paints requires careful preparation so that things don’t go wrong later down the road!
  • Keep your paintings dry until use; otherwise, this could lead to problems such as yellowing or cracking over time
  • Don’t cover up any areas that are already painted in oil-based mediums (such as gesso) because they’ll most likely be ruined if exposed to this stuff
  • Another problem that can occur is how the paint starts drying unevenly due to how it was mixed. In that case, you should avoid shaking or stirring your painting too much after adding any of these types of chemicals. That way, things don’t get out of hand!

Medium Type 2: Acrylics

how to thin oil paint with medium

If you’re looking for an easier way to thin your oil paints, try using some acrylic medium. It will help make the paint less viscous so that it’s easier to apply while still retaining its color properties as-is.

Acrylics already have a much thinner consistency, which means that the resulting mixture will be easier to work with!

Important Notes:

  • Avoid thinning your paints too much if you’re using colors on top of white. This can cause them to look more transparent and light than how they appear in their container
  • Just like anything else, though, take care not to overdo it. Too much of this might also lead to problems down the line. In particular, avoid using this method if you’re working on top of white surfaces because the colors might not look as bright and vibrant as how they do in the container

Acrylic Gum

Consider using acrylic gum if you’re looking for a more specialized way to thin your oil paints. It is a substance that will help make the paint less dense so that it’s easier to apply while still retaining its color properties.

This type of medium isn’t recommended for all types of oil painting. Some may react poorly, depending on how thick they were originally (oil-based varnishes will usually stay unaffected).

Medium type 3: Solvent

Another way to thin oil paint is using solvent for a moderate drying time. If you want to achieve a matte finish, this is the method to go. Indeed, not all solvents can be used for thinning oil paints; you can choose among these two most popular choices:

  • Mineral Spirits
  • Turpentine

These mediums feature a watery consistency, thus creating a low level of viscosity for your colors.

Important Notes:

  • You should wear a mask to prevent the solvent fumes from hurting your lungs over time, especially if you frequently thin and draw oil paints.
  • Painters should only use mineral spirits to thin their first two or three layers of paint. Also, use less solvent and add more oil for the next layer compared to the previous one
  • Furthermore, do not use a solvent medium to thin your paint if the current layers on your paint are thick and oily.
  • Indeed, high-quality and artist-grade solvents are recommended for use when thinning your oil paints.

Medium Type 4: Water and Gels

Finally, you can also thin the paint by adding water. However, this should only be done as a last resort, as it will affect the quality of your painting. If you decide to use water, add just enough to make the paint more manageable and mix well.

On the other hand, using gels is also recommended to achieve a high level of viscosity with your paintings. For instance, you can work with safflower Alkyd as it is a solvent-free gel.


As you can see, there are many different ways to thin oil paint depending on the desired results. Using the right medium and solvent can make your painting process easier and achieve better outcomes!

Also, you can use two methods simultaneously, like adding oil and solvents to thin your paints. Therefore, feel free to experiment with different methods and find what works best for you.

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