Updated: Jan 19, 2022
What an oil painting medium is, has both a simple and complicated answer. The simple answer is that oil mediums do the same thing for oil paints that water does for watercolor.
To make watercolors work you need water, to make oil paints work you need oil (in both cases the water and the oil are the "medium" of their respective paints).
Oil mediums do the following:
- extend your oil paints to cover more area
- quicken or retard the drying time of your paints
- modify the texture of your oil paint, making it thinner or thicker
- alter the paint's sheen, making it high gloss, satin, or matte
What medium is a good starter medium?
How do I use a medium while painting?
To start it is best to think of using the oil medium just as you would water in watercolors. With watercolors sometimes you want your paint to be really thin so you add lots of water. Sometimes you want your watercolor paint to be bolder, but with still movement so you add less water. Sometimes you want a thick dry stroke so you add little to no water.
Now lets translate that into oil painting. Add five or so oil drops onto your palette or a teaspoon or so of gel, a little goes a long way. Add a little directly into paints with a palette knife if you want a thin glaze to your paint. Dip your brush into your medium and then into your paints if you want bold color that is smooth. And no medium if you want thick brush strokes (there are mediums you can add to enhance your Van Gogh strokes while using less paint, more on that later).
Now for the more complicated answer (this is going to be long)
There are a billion different types of pre-made mediums and a billion DIY medium recipes all over the internets. When I first started oil painting I found the amount of mediums, the information on each medium, and the knowledge needed to understand that information so overwhelming. So here, let's keep it simple. Each artist will eventually find their own groove, their own preference, or like me, your preference will change as your painting ability matures and develops; but each artist also needs a starting point.
First let's take a quick look at traditional mediums, then pre-made mediums, and then a basic recipe idea.
Traditionally mediums are made up of two parts: solvent (drying agent) like turpenoids or mineral spirits and oil (retarding agent) like linseed or stand oil .
Artists adjust the ratio of turpenoid to oil in order to either slow down or speed up the drying process. More turps means a faster drying time. More oil means a slower drying time. Scroll down to the Recipe section of this post to see how to combine oil and solvents.
Pre-made mediums take the guess work out of needing to come up with a useable ratio. For example, too much turps will ruin the integrity of the paint pigment. Too much oil and you will get a greasy mess.
There are so many more, but it is hard to go wrong with these three. Some pros and cons however.
Pros: Creates a great hard, glossy film for your painting, leaves a nice shine, and you will almost never have dull spots. It is a gel like substance that you just scoop out with palette knife, put on your palette, and dip your brush into when needed, or mix directly into large amounts of paint. This was the first medium introduced to me and it is great.
Cons: It is so stinky. Do not use in a closed room and do not use around pets and children. It is toxic. Purchase a small bottle as first, because once open the liquin inside the bottle will start to dry out. You cannot add oil in order to extend drying time. It is what it is.
Pros: Creates a great hard, glossy film for your painting. It is a better beginning choice than just Galkyd, as it allows from both smooth and heavy brush stroke application. It is also not stinky, as it is made with Gamsol Odorless Spirits. It gives your painting a nice gloss without dull spots. Use a dropper to put 5-10 drops onto your palette at a time, dip your brush in when needed, or mix directly into large amounts of paint.
Cons: While it is made of some of the best, odorless spirits, it is still made with a solvent and is still toxic. Do not use in a closed room and keep out of reach of pets and children.
Walnut Alkyd Medium
Pros: Non-toxic and eco-friendly. It is solvent free, decreases drying times, but slower than the other two. It leaves paints with a matte-ish finish, and can easily be combined with M. Graham's walnut oil to extend drying time. I use this medium, usually in a 50/50 ratio of oil to alkyd. Use a dropper to put 5-10 drops onto your palette, dip your brush when needed, or mix directly into large amounts of paint.
Cons: The painting surface does not dry hard and can leave you with dull spots (dull spots can be corrected, but the soft surface and dull spots are annoying). You can use it in a closed room and it is safe to be around pets and children (however, you don't want them playing with it).
Basic Traditional Recipes
Traditional Recipes are made of a solvent and oil. Like everything there are so many solvents. If you want an exhaustive list read here. My top two (even though I try to avoid solvents) are Gamsol and Eco-House Orange Terpene.They both do the same thing. You can also use M. Graham's Walnut Alkyd in place of a solvent, albeit it does not dry as quickly.
Also like everything, there are so many different oils and each does its own thing. My top two are Refined Linseed Oil or Walnut Oil. If you would like you can read more about some standard oils below or here.
A Basic Recipe
Note: This incorporates the Fat over Lean principle, which I will be covering in separate post.
Leanest: 5 drops of alkyd or solvent of choice
Leaner: 4 alkyd / 1 drop oil
Fattiest: 1/5 drops of oil
What do I use?
I use 50/50 walnut oil to walnut alkyd. I do like the way it moves the paint, but I hate the soft paint film it leaves after drying. I have been considering switching to Galkyd lite, but I paint with my little ones around and not having solvents around them is a must for me.
Well that was painfully long. Did I miss anything? Let me know in the comments and happy painting!
This is a rewrite of two of my original blog posts: Types of Mediums: The Simple Option and Types of Mediums Extended: Oils, Thinners, Mixtures, Questions, etc.