15 Easy Ways On How To Thicken Oil Paint – Artist Tips

There are several methods for thickening oil paint, including using:

  • thickening agents like impasto medium
  • painting butter
  • cold wax medium and linseed oil
  • mixing with additives like drying oils, resins, and powdered marble
  • using texturing techniques like palette knives, brushwork, and impressionist techniques.

By using these techniques, artists can create layered, tactile works that showcase their unique vision and style.

Ways to Thicken Oil Paint

Using Thickening Agents

Impasto Medium

This is a gel-like medium that can be added to oil paint to increase its thickness and create impasto effects. It can also enhance the paint’s color and shine.

Impasto medium can be used straight from the jar or mixed with oil paint.

When using impasto medium, it’s important to make sure that it’s thoroughly mixed with the paint and not over-applied, as it can crack when it dries.

Impasto Medium
Impasto medium

Painting Butter

This is a thick, buttery substance that can be added to oil paint to increase its viscosity and texture.

Painting butter is made by mixing beeswax and damar resin with linseed oil.

It can be melted and added to oil paint to create thick, textured strokes.

However, it can be difficult to mix with some colors, and it can also affect the paint’s drying time.

lukas oil impasto painting butter medium main
How to thicken oil paint with painting butter

Cold Wax Medium

This is a mixture of beeswax and solvent that can be added to oil paint to create a matte finish and increase the paint’s thickness.

Cold wax medium can be applied straight from the jar or mixed with oil paint. It’s important to note that it can also affect the paint’s drying time.

Gamblin’s cold wax medium is one of the best on the market.

Gamblin’s cold wax medium
Gamblin’s cold wax medium is one of the best on the market.

Linseed Oil

This is a commonly used medium in oil painting that can also be used to increase the paint’s thickness.

When added in small amounts, it can enhance the paint’s flow and transparency.

However, it can also make the paint more prone to yellowing over time.

Refined Linseed Oil
Refined Linseed Oil

Beeswax Medium

Beeswax medium is a thick, buttery substance that is made by mixing beeswax and damar resin with linseed oil.

When added to oil paint, it can increase the paint’s thickness and create textured strokes.

It’s important to note that beeswax medium can be hard to mix with some colors, and it can also affect the paint’s drying time.

So while it can be used to thicken oil paint, it’s important to use it carefully and experiment with different ratios to achieve the desired effect.

Beeswax medium
Beeswax medium

Oil Painting Ground

Oil painting ground can be mixed with paint to create texture and thicken it, but the results may not be as effective as using other thickening agents or additives.

Oil painting ground is typically used as a surface preparation, applied to the canvas before painting to create a smooth and even surface.

Mixing it with paint can create a gritty texture, but it may not increase the paint’s thickness as much as other materials.

Additionally, oil painting ground can affect the paint’s drying time, so it’s important to use it in moderation and test for compatibility with other materials.

Oil painting ground
Oil painting ground

Mixing with Additives

Drying Oils

Drying oils like stand oil, fast drying linseed oil can be added to oil paint to increase its thickness and transparency.

These oils can also enhance the paint’s glossiness and depth.

However, it’s important to use them in moderation, as they can also increase the paint’s drying time.

Drying Oils
Drying Oils

Resins

Resins like damar resin or mastic resin can be added to oil paint to increase its thickness and create a glossy finish.

Resins can also enhance the paint’s durability and make it more resistant to yellowing over time.

It’s important to note that they can also affect the paint’s drying time and may require solvents to remove from brushes and palettes.

weber oil painting mediums 4oz 8oz 16oz
How to thicken oil paint with resins

Powdered Marble or Fine Sand

Marble Dust is a type of special powder that’s made from something called calcium carbonate. It’s very, very fine, which means it’s extra small.

It’s also very dense, which means it’s very heavy for its size. When artists mix Marble Dust with oil paint, it can make the paint thicker and give it a rough texture.

As most marble dust is white, it will not alter the hue of your oil paint but you really need to mix it well to ensure that all the dust is covered in oil paint or it will not stick.

Fine sand can also absorb some of the oils from paint, making it appear thicker.

Adding powdered marble or fine sand to oil paint can be useful when creating a base layer for a painting or when trying to achieve a more organic look.

It can be difficult to mix with some colors and may not be suitable for all types of paintings.

I personally do not like this approach unless I wanted an very textured oil painting base.

As you may or may not know, my style of oil painting is smooth but for artists out there who like to create some texture give this a try.

Calcite, Barite, Calcium Carbonate or Bentonite

Make a paste with either calcite, barite, calcium carbonate or bentonite with some linseed oil and then mix it with your oil paint (you do not need to mix all of them).

Specialty art suppliers typically carry materials such as Calcite, Barite, and Bentonite that can be used to thicken oil paint and add texture to paintings.

These materials are also commonly found in pottery supply stores, where they are used in the creation of glazes.

Texturing Techniques

Palette Knife

Palette knives can be used to apply thick layers of paint to a canvas, creating a textured and impasto effect.

Palette knives can also be used to scrape paint off a canvas, revealing layers of color underneath.

Brushwork

By using thicker brushes and applying paint in a more vigorous and expressive manner, artists can create texture and thickness in their paintings.

Impressionist Techniques

Impressionist techniques like stippling or dapping can be used to create a textured, impressionistic effect in oil paintings.

These techniques involve applying small dabs of paint to a canvas with a stippling brush or other small tool.

Tips and Considerations

When using thickening agents and additives, it’s important to take safety precautions and follow manufacturer instructions.

Some of these materials can be flammable, toxic, or irritating to skin and eyes.

Test For Compatibility

It’s important to test for compatibility when mixing different types of thickening agents and additives.

For instance, mixing oil-based additives with water-based paint can cause separation and other issues which will just ruin your painting and cause untold issues.

Add More Oil Paint in Layers

You can layer on more oil paint in layers. As each layer dries, slab on more oil paint and wait for the skin to develop before applying another layer.

This will give you a thicker oil paint but a word of warning, this will take a long time to properly cure and dry as you are basically slowing down the oxidization process of oil paint where the oil ‘dries’ leaving a hardened layer of pigment and medium.

Add More Pigment

Oil paints can also be thickened if you mix your own batch or if you buy the right colored pigment.

All you need to do is add more pigment to your oil paint and this will increase the ratio of pigment to oil, leading to a thicker impasto of paint.

The analogy I like to use is that of adding more flour to dough if you made it too watery.

Reduce The Amount of Oil In Oil Paint To Thicken It

Another low tech hack for how to thicken oil paint is to take your oil paint mix and put it on a thick sheet of cardboard or newspaper and let it soak up and absorb the oil from the oil paint.

Use a palette knife to mix the oil paint around and once you have your desired oil paint thickness then scrape it up and place it back on your painting palette.

Do not use solvents

Using solvents may seem like a good idea as it should thin the oil paint out and then it can evaporate faster leaving just a thicker goo of oil paint but no, it does now work this way and don’t do it.

Do not mix house paint or latex based wall paint thickening agents

Thickening agents with latex for houses are not suitable for oil paints made for art.

The pigments in artists oil paints are different to house paints and while it may appear to work the long term results are unpredictable.

Finally

You should experiment and play with different techniques to find what works best for their unique style and preferences so when using my tips and considerations for how to thicken oil paint.

I suggest making a small batch and doing a spot test over a few days to see if you like the results and if they work for you.

Leave a Reply

Your email address will not be published. Required fields are marked *