Demystifying Water-soluble Oil Paints

The Science of Art by Mot Tuman

Ready to get into water-soluble oil paints, how are they different from traditional oil paints and how do they work? Join Mot in the “Science of Art” as we explain the secrets behind water-soluble oil paints in this article with a full video.

Find in this article: explanations, images, video and faq’s below

How to Start with Water-Mixable Oils

1. Pick a starter line: Choose a water-mixable brand (e.g., LUKAS Berlin, Cobra, Artisan, Duo Aqua) and 8–12 core colors.
2. Block-in lean: For the first layer, thin paint lightly with water or a water-mixable thinner; keep it lean.
3. Use matching mediums: Switch to water-mixable linseed/safflower oils and gels for body and flow in later layers.
4. Mind compatibility: You can mix with traditional oils, but too much traditional paint reduces water-mixability. Keep it minimal.
5. Clean up solvent-free: Wipe, then wash brushes with soap and water; finish with a brush cleaner if needed.

Pro tip: Follow fat-over-lean—add oil content gradually in later passes for durable films.

In this Science of Art article: What makes water-soluble oils different from traditional oil paint and what is in their formulation and how are they are used. They are traditional oil paint that has been modified chemically to be water-soluble. (See Full Length Video below!)

“Some of you who have never used water-soluble oils before might be wondering what exactly the difference is between them and traditional oil paint. The answer is not much. Surprisingly, water-soluble oils are just traditional oil paints that have been modified chemically to be water-soluble and there’s a few different ways that manufacturers do that. 

“But before I get into exactly how they do it, I want to show you guys exactly why just adding water into oil paint isn’t going to work.”

“You can see that oil is known as hydrophobic which means it doesn’t like to interact with water. It doesn’t like to bond with water and it’s going to stay separated from the water no matter how much water you include. 

“When you think about having a water-soluble oil paint you’re probably wondering how you can solve this problem of the oil never wanting to interact or be broken down by the water.” 

Why Use Water-Soluble Oil Paint?

“One of the reasons people might want to have a water-soluble oil paint is that the traditional solvents used for oil paint, like turpentine or mineral spirits, tend to have carcinogenic or toxic fumes that can be hazardous to breathe in without proper ventilation or over a long period of time.” 

“So, a lot of people have wanted to have an oil paint that has a less toxic or safer solvent to use, which is how water-soluble oils came about. But in this case water is not able to work as a solvent for traditional oil paints because oil–like I said earlier–is hydrophobic. It’s not going to want to be broken down. 

“A solvent, while we traditionally think of it as something that is toxic or hazardous because of that association with traditional oil painting, can really be anything. Water works as a solvent for watercolors and for acrylic paints. 

“A solvent is any liquid that can break down some other substance. In this case, water cannot be used as a solvent for traditional oil paints, but there is a way that we can modify oils in order to make them be broken down by water.”

The Magic of Water-Soluble Oil

“I want to show you guys the difference between what I just showed you and mixing water with a modified linseed oil that is meant to be water-soluble.”

“You can see how this doesn’t bubble up and form larger blobs like our last example did. It breaks down a bit more and even starts to dissolve. You can see it becomes one with the water and we get this hazier look rather than before where the oil was just sitting on top.”

What Is The Difference?

“How do we get from the linseed oil that could not dissolve in water to the water-soluble linseed oil that could? There’s really only one ingredient that you need to add into something to make it water-soluble and that ingredient is known as an emulsifier. 

“An emulsifier can mean several different things. The most basic type of emulsifiers we have is just the act of mixing two things together. So, if you ever noticed that your peanut butter or your mayonnaise are separating from each other over time, that’s because they have been emulsified together. 

“You need to remix them together in order to reincorporate that oil into the rest of the ingredients. They have been emulsified but they’re not chemically bonded, so they’re still going to separate over time. 

“That kind of emulsification isn’t going to work for a water soluble oil paint, but a different kind of emulsifier known as a surfactant will. A surfactant can come in many different forms but the most common form of surfactant that we know is a dish soap.”

“I’m going to show you guys what happens when I mix a surfactant like dish soap into oil paint.” 

“The reason that a surfactant–like what’s found in the soap–is able to work in order to break down the oil paint is because the molecule in the surfactant has two different sides to it that kind of work as a chain between the oil and the water. 

“One side of this molecule is hydrophilic, meaning that it likes water and it wants to bond to water molecules, and the other end of this molecule is hydrophobic, meaning it does not want to bind to water molecules but it is inclined to bind to oil.” 

“Essentially, what happens is that the surfactant is working as a link between the two. It’s going to hold the water on one side and the oil on the other and it’s going to be able to break apart that oil. That way that’s part of the reason why using soaps like this to clean your brushes after you work is effective in getting all of the oil out.” 

“There’s a little bit of a risk here if you’re trying to do this. You are risking the archivability because adding the right amount of soap into the oil paint to be able to get it water-soluble without breaking it down too much is kind of tricky. There’s a risk of this not being archival because we’re using something that has additional additives that we’re not aware of.”

Can I Use Water-Soluble and Traditional Oil Paint Together?

“There are several caveats to combining water-soluble and traditional oil paints. Once the water-soluble paint starts to cure it actually starts to act the same as a traditional oil paint. What happens is that as the water evaporates off it is going to take that emulsifier with it. So once it begins to cure it will no longer be water-soluble and it will act and look the same as a traditional oil paint.”

“You might be wondering what kind of mediums you can use with this. We get questions very frequently about how someone wants to use their traditional oil painting mediums with the water-soluble oil paints and vice versa. 

“What effects would that have on your paint? The breakdown is that you can use traditional oil painting mediums with your water soluble paints and vice versa, but there’s a little bit of a caveat. 

“Traditional oil painting mediums are not going to have the emulsifiers to be able to make them water-soluble. So, if you’re mixing traditional mediums into a water-soluble oil paint it’s going to make it less water-soluble. It still will to some extent, but it’s not going to have the same reactions. 

“You’re essentially turning it back into a traditional oil paint; the opposite can be true as well. If you’re taking water-soluble mediums and you’re mixing it into a traditional oil paint you can kind of make it water-soluble to some extent, but it’s never going to be as water-soluble as a pre made water-soluble oil paint with water-soluble mediums.”

Conclusion

“The reason that this traditional oil paint was able to break down with water was because of that molecule in the surfactant that has that one hydrophilic end and that one hydrophobic end creating a chain between the oil paint and the water to make it soluble.  When mixing water-mixable oils with traditional oils, keep traditional content low (brands like Cobra advise up to ~20%) to preserve water-mixability.

“But you can see here just adding a surfactant in, like a dish soap, is going to add in some unknown variables, so we’re not sure about the archivability of this. We’re not sure how it’s going to affect the drying time. 

“So there’s a little bit of give and take there if you’re trying to experiment at home with your own water-soluble oils.

That’s why a lot of companies will make sure to have actual in-house chemists

“That’s why a lot of companies will make sure to have actual in-house chemists working on their products so that they can be sure to add in the correct amount of surfactant and surfactants that won’t have any additional additives that will potentially mess with the archivability, the sheen, and the quality of your oil paints over time.”

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Frequently Asked Questions

Do Water Soluble Oil Paints Dry Faster?

A: Water soluble oil paints may initially become touch-dry faster than traditional oils paints, but once they begin to cure and the additives that make them water soluble evaporate out, they become chemically the same as traditional oils paints and will take the same amount of time to cure. 

Do You Need Linseed For Water-Soluble Oil Paints?

A: Yes, the methods for painting with water-soluble oil paints are the same as for traditional oil paints. It is recommended that you use a water-soluble mediums specifically made for Water-soluble paints, otherwise your paints could lose their solubility. 

Can You Make Your Own Water-Soluble Oil Paints?

A: While you can mix in a small amount of dish soap into oil paints to make them water-soluble, the consistency it creates is unlike water-soluble oil paints sold on the market and there are concerns with additional additives affecting the paints quality and archivability. 

What Oil Paints Are Water-Soluble?

A: There are several water-soluble oil paint brands on the market, including Lukas Berlin and Cobra water mixable oils. 

What is the Difference Between Water-soluble and Water-Mixable?

A: Water-soluble and water-mixable are two common terms used for oil paint that has been modified to be thinned down with water. While they use different wording, the two terms mean the same thing.

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More Resources

• How Real Oil Paint Was Made
• Water Mixable Oil Paint vs. Traditional Oil Paint
• Synthetic vs. Natural Brushes for Oil Painting
• Brushstrokes & Molecules: Unveiling the Chemistry Behind Oil Paint
• What is Underpainting in Oil Painting?