Occasionally, I’ll hear from a painter who’s developed sensitivity to odorless mineral spirits (OMS), the solvent for oil painting. I think traditional oils, gouache and watercolors are the safest and least environmentally-damaging of mediums, but some people get headache from OMS. There are workarounds for solvent-free oil painting that can minimize or eliminate exposure.
A reminder: the binder in oil paints are drying oils: mostly linseed oil, but occasionally poppy seed, safflower or walnut oil. All are edible. The pigments used in paints are the same across all mediums. Avoid the heavy-metal pigments, and your risk from painting is low, no matter what medium you use.
The toxicity of OMS (refined to remove aromatic hydrocarbons) is also low. It’s not likely to hurt you unless you drink it. You can fly with Gamsol, because its flash point is so high it’s not even considered combustible. If OMS gives you headache, I’d start by switching to it.
Consider a fan or an activated carbon filter for your studio. (HEPA filters will not remove volatile organic compounds from the air.) And empty the trash after every painting session. Not only can OMS- or oil-soaked rags lower air quality, they’re also flammable.
Oil painting requires both solvent and a medium. The solvent evaporates completely and is used to thin paint and clean brushes. Mediums become a permanent part of the paint film, altering gloss, body, and drying time. Mediums bind the pigment, while solvents dilute it. But many mediums contain solvents to speed dry time or control gloss.
There are many solvent-free mediums available on the market, including Gamblin’s solvent-free gel, but the oldest and most thoroughly-tested is plain old linseed oil. Just make sure you buy artist’s grade to avoid yellowing.
I’ve had many students who avoid the worst of OMS sensitivity with careful brush protocol. They wipe, rather than swish, their brushes during a painting session. (That is a good practice for preserving the fat-over-lean rule anyway.) At the end, they clean their brushes with coconut or other kitchen oils and then wash them with a good brush soap. The amount of OMS needed for the painting process itself can be what’s held in a small palette cup.
What about miscible oils?
I’ve never met a miscible (water-mixable) oil paint that behaves like traditional oils. They’re marketed for less-toxic brush clean-up and simpler waste disposal, but neither is really true. The environmental problem with paint is in the heavy-metal pigments. They shouldn’t be going down your drain any more than they should be in a landfill. OMS can be poured into a jar and the pigment particles allowed to settle. These can then be disposed of as solid waste, if you started without heavy-metal pigments.
My problem with miscible paints is that they’re stodgy. That’s no surprise, since they are made by the same process (saponification) that we use to make soap.
The trade-offs of solvent-free oil painting
Solvent-free mediums tend to be oil-rich since they’re not cut with OMS or varnish. They must be used sparingly to maintain good film integrity. It’s also very difficult to underpaint in thin washes without OMS, so a very direct alla prima painting technique must be substituted for the layering typically used in oil painting. If you choose miscible oils, the drying times and handling characteristics are different from traditional solvent-thinned oils. Lastly, you won’t get away with wiping down your brushes and setting them aside to clean later. They must be cleaned with soap and water after each painting session.
(I’ll share my Sedona paintings with you on Wednesday.)
Have you had a look at Michael Harding’s Miracle Medium 0? I am not sensitive to OMS (Gamsol is what I use) but thought I would give this a try through the winter when the house is more closed up-it seems to have an even better safety profile. I wonder if anyone sensitive to Gamsol/OMS has given it a try with success..
SDS https://324c4af6.delivery.rocketcdn.me/wp-content/uploads/2023/08/MICHAEL-HARDING-MIRACLE-MEDIUM_GHS-SDS_MHA2023-068.pdf
Thank you for all the time you spend to create interesting and relevant content. I’m a diligent reader!
Good article Carol! I have been an anti-advocate for OMS since I first discovered them. (Frankly, yuk. Although I know some people are doing nice work with them. I can’t get past the feeling that I’m painting with soap!) And for those of your students and readers who want additional information, I would refer them to Virgil Elliott’s book “Traditional Oil Painting” and the Facebook page of the same name, as well as George O’Hanlon’s page “Painting Best Practices”. Both have a long history in Painting, and conservatorship, and have forgotten more than most of us will ever know. It was nice to see you in Sedona and I really enjoyed demoing with you. Congratulations on the win and the sales!
Carol you need to try Cobra watersoluable oils as their consistency is much more like regular oils. Although I do not compare as I use them but just enjoy their versatility. The watersoluable oils are much easier to clean up after with water having already wiped as much paint from your brush on a rag or paper towel. Use a thin acrylic underpainting like toning the canvas with regular oils. Apply watersoluable oils on top of the already dried acrylic toning to do your painting!