Is walnut oil really a substitute for mineral spirits?
Not exactly.
This is a question I’ve been asked dozens of times through email, Facebook, and during our community webinars. It’s also a question I’ve had myself, which is why I’ve done so much research on the subject over the years.
For this blog post I’ve done my best to condense the information into a short and easy to digest explanation, but please let me know if more information or details would be helpful.
I like using walnut oil because it keeps the colors from getting that dry sunken look, but it doesn’t achieve the same watercolor like washes that we can get so readily with mineral spirits.
M Graham & Co walnut oil
If we are planning to have the background wash visible in the final painting and want the colors to flow together like watercolors, then mineral spirits is a better choice than walnut oil. If we intend to cover most of the background with thicker paint and want our shadow pattern shapes to retain their more glossy appearance, then walnut oil or straight paint is the better choice.
Depending on how much we use, mineral spirit washes may not be entirely sound either because the mineral spirits dilutes the oil binder (walnut, linseed, poppy or safflower) and can cause the paint layer to become thin and weak. Since it has only been around since the 1920’s we don’t know for sure what effect it might have on our paintings. I wouldn’t worry though if you use mineral spirits – artists took to it like a moth to a lamppost and we haven’t heard anyone stomping around complaining that their investment art is falling apart.
Gamblin Mineral Spirits
Since I started using a tiny bit of walnut oil for my washes I haven’t really missed the mineral spirits – much.
I would caution not to use too much walnut oil, especially on acrylic gesso, because it will tend to bead. The reason it beads up is because of the nature of the mechanical bonding that occurs between the oil and the acrylic. Acrylic is plastic and porous – it has lots of tiny holes we can’t see with our eyes. The oil paint attaches to the acrylic by filling in and holding on to those holes. When too much oil is used, the holes fill up and the oil has nowhere to go so it beads up. At that point it will need to be wiped off and more pigment (paint) added to the mix.
Leak proof canister to carry my walnut oil in for plein air painting.
If you decide to use walnut oil for your washes, take heart – there are artists from the 1800’s and early 1900’s who used soupy oil washes that have held up beautifully for more than a hundred years (not on acrylic grounds though, since acrylics are fairly young tykes – not used by artists until the 50’s).
Here’s an example of one of my recent paintings, done completely without mineral spirits:
Take a Ride on Reading 12×16 by Bill Inman
Have fun and keep experimenting. And then let us know what you discover along the way 🙂
Hi Bill. I am trying a mixture of about 40./60 Gamsol and stand oil and like the results too. :o).
Many artists like a similar mixture Linda, glad it is working for you! That’s the fun of experimenting – discovering what works for us and makes painting even more enjoyable.
Can you substitute walnut oil for cooking? Is it the same?
Not really Mary. Oils used for painting have characteristics that allow the suspended pigments to harden and dry, while most cooking oils won’t. I would recommend sticking with the oils used as a binder in paints – walnut, poppy seed, linseed or safflower. They are used as binders because they are poly-unsaturated, while store oils are generally mono-unsaturated which don’t dry correctly for painting. If you really want to use a medium then either linseed or walnut are the best choices because they dry with the toughest films. They yellow more than safflower or poppy, but the latter lack linolenic acid (which is why they yellow less and why they form a weaker paint film). You’re better off using paint straight from the tube if possible for many reasons – anything added to the paint can cause longer-term problems.
Does the brand of oil matter? I tried boiled linseed oil from lows, and it made my paint awfully yellow. I feel as though the gamsol linseed oil did not have such a yellow tinge. I really enjoy thinning down my paints yo do glazes. However, I do not care for turpentine or mineral spirits. They claim to be odorless, but the ones I have purchased smelled quite strongly.
Thank you for listening.
I use walnut oil but not for washes. Mineral spirits just washes paint away, I prefer turpentine.
Turpentine creates beautiful oily washes Sharon, but the fumes are so toxic to our bodies I have mostly stayed away from it. One of my professors when I was in art school had to give up oil painting because of turpentine and I have heard many other horror stories from professional artists since then. Make sure you have excellent ventilation when you use it.
As a very inexperienced ‘artist’ ha ha I have used Almond oil with some success. however drying time increases. Also used Rosemary oil which is rather pungent. I will try Safflower oil and Gamsol if I can get them.
Walnut oil is a binder, turpentine is a solvent. A nice painting medium is half oil half solvent. Painting with solvent alone undermines the durability of the paint.
Haven’t heard of using Almond oil Gordon – I would love to hear how well your paintings fare over time.
I studied with Alex Shundi for a couple of years. He recommended a medium of one third linseed oil, one third damar varnish and one third good gum turpentine. He Usedmineral spirits only to clean brushes an palette. The only exceptions were for an initial sketch or toning a canvas when you needed the quick drying.
That mix was a standard for artists for a long time Daisy. Turpentine works beautifully for washes, but I shy away from anything that emits toxic fumes. Damar has been replaced by many with more recent mediums that have less of a tendency to yellow and bloom, but since I don’t use mediums I don’t have any good recommendations otherwise.
I’ve only used Walnut oil in glazing. I’m confused on the wash because isn’t Walnut oil with oil paint a fat?
Yes it is Susan – oils make the paint fat while solvents thin. I have never worried too much about the fat-over-lean conundrum because I paint wet into wet mostly and because I use so little of it for my washes – they are never soupy like a mineral spirit wash. Then again, artists in the past have used soupy oil washes without any cracking issues that might be caused by longer and slower drying times. Fat over lean is much less of a problem when we paint without mediums and complicated processes. If we get too worried about it we would need to take into account the slower and longer drying times of individual pigments like an umber compared to a cadmium – beyond the scope of most artists and generally not necessary at all to concern ourselves with. Most of us will never be in museums (and look at the work that is anyway – created with all kinds of non-archival practices and materials) and the use of reasonable painting practices will last at least our lifetimes and the lifetimes of our collectors. I paint on panels now, but I still have some of my canvas paintings from the early 90’s and even they are holding up incredibly well even though I haven’t been gentle with them. One of them has some paint that is 1/4 inch thick and only two small cracks in some white clouds – and those came from something pushing the painting from the backside when it slipped down a wall. It is definitely a good idea to understand the fat-over-lean principle, but maybe not to over-complicate painting because of it. Have you heard of specific horror stories from someone not following that principle with the use of too much oil early on? I am always interested in info that will help our community.
Hi Bill, I was told by a famous artist on cape cod to try walnut oil so I did and I’ve been very happy with the oil colors staying bright and true.
Great to hear Diane! So far so good for me as well – although it’s only been about 6 years since I stopped using mineral spirits.
Have a question. I have a couple of oil paintings that were done in the late 50’s. I need to clean and put something on them to get the paint that seems to have sunk in in places. What should I use? Not experienced with this so don’t want to ruin them.
I’m not sure either Karen, restoration is a tricky business because there are so many variables that can affect the outcome. You don’t want to use water or soap in any way. If they are historically valuable, you will want to consult or hire a professional. If they are more sentimental or just for decoration you might try cleaning with a duster first and then some mineral spirits or oil like walnut or linseed and wipe gently with a lint-free cloth. Then let it dry for a few weeks and if it looks clean use a varnish like Gamvar to brighten it up.
I have been using 50% M. Graham walnut oil and 50% M. Graham Walnut Alkyd mix for my oil paintings. Anyone else?
I tried the galkyd once and couldn’t stand the stickiness and quick dry time Linda. I have heard other artists say they like the M. Graham Alkyd, but they use just a tiny amount so the paint doesn’t get sticky – also some said they do the same thing with the oil and alkyd and it works great.
Good question I painted some in the 1980s and never varnished them, how to clean them now and what to use on them? Well tried twice to comment and selected FB think they both failed……or worked twice. Plus am on FB already in a different window:)
I have not worried myself much about that before Patricia, but I will make a point of researching good cleaning methods.
Hi, I have been using a mix of half walnut oil & half mineral spirits for my initial layer of underpainting, then putting it away & then sticking to my oil paints without anything else. It works well especially when you can finish your whole painting in one sitting. It is important to clean my brush frequently to keep colors clean & avoid picking up the underpainting color & making mud.
Thanks for the article! Is it appropriate to mix walnut oil with mineral spirit to create a medium? For my first layer, I would use mineral spirit plus paint? Second layer, I would use 1 part oil 3 part spirit plus paint? Third layer, 2 part oil 2 part spirit plus paint? For final layer, 3 part oil and 1 part spirit plus paint? I’m asking because I want to avoid cracks since I paint in layers. Thanks!
Does anyone know where I can find a list of m. Graham oil paint colour drying times? I know the colours dry at different rates, but I cannot find a comprehensive list anywhere.