Part 2: Assembling a solution – How Not to Poison Yourself in the Studio
by David Molesky
Paint mixing station at Molesky’s Brooklyn studio, early 2020.
Having realized the adverse health effects of solvents in the studio, I set to work to improve my own studio situation and ways to communicate this discovery and help my painter friends avoid poisoning themselves while painting.
Looking online, I could see from blogs and scientific papers that the aromatic ring compounds found in solvents are indeed irritants to the lungs, skin, and brain and can become extremely dangerous over prolonged exposure. Full-time oil painters are at the greatest risk.
Painting rags probably contribute the greatest toxic threat in the practice of oil painting. The rag’s structure makes for greater surface area for the solvents to become airborne. Not to mention that these rags soaked with oil mediums are also fire hazards that can potentially self-ignite and burn your studio down! I had heard that Lucian Freud’s studio burnt down on two occasions because of oil soaked rags combusting.
It is important to dispose of soiled rags properly. If you will use rags with solvents in the studio, you should take additional precautions — wear gloves and then properly dispose of the rags immediately after using them in a designated sealed container. When I use rags during a painting session, I collect them in a cookie tin. Then at the end of the session, I collect the contents of the tin and put it into one of my dog’s poop bags (unused of course — newspaper bags would also work). Then I pour water into it, squeeze out the excess water, tie it off, and then take it out to the garbage.
I must note that I do allow solvents into my practice on occasion. If I am beginning to work on a surface that has been sitting around for many months in my studio, I want to clean off all the atmospheric oil and dirt from the surface before adding paint. In this way I can ensure that the paint layers will make a strong bond to the surface. Sanding also helps create “tooth” and a better surface for binding. But there is also a solvent-free option for this purpose. Many of my friends insist that a dilute ammonia spray, like windex, works just as well. Not that ammonia is all that less toxic to breathe.
If you can avoid using solvents when cleaning up, then your brushes (and health) will last longer. One may ask, “don’t I need solvents to get the paint out of the bristles?” No. But if you let your brush dry caked in paint, then you might need to let them sit in a solvent for a while. Best to just stay on top of things and clean your brushes at the end of every session. If you do this, warm water and a good brush soap will do the trick. I and many of my painter friends prefer Jack’s Oil Soap. I also use a nail brush or wire brush to help clean the bristles.
If for some reason you have to leave before cleaning your brushes, drop them into a jar of oil or better yet a small roller pan. Allowing the brushes to lay on their side rather than sitting on their points will keep the bristles in a better shape. Sometimes I’ll add one drop of clove oil into walnut oil to slow down the drying time of this container of oil and to help keep it from getting super thick. I have heard other people use safflower oil instead (but I feel more confident to use the same oil I am painting with.)
If you choose to leave the brushes in oil, you can just take the brush out of the pan and wipe the excess oil off when you are ready to begin again. You could wipe this oil off on a rag, but what I often do is paint a stroke of oil onto my glass table to identify the color that was on the brush previously. Then rather than having to deep clean this brush, I can designate its use for similar colors. (For example, if it’s dark then I obviously don’t use that brush for my lightest colors).
As I mentioned in part 1, you are better off not using solvents in your medium, especially if you find yourself wiping your brush onto a rag. The rag will increase the surface area for the solvent to evaporate into the air and it will get absorbed into your skin if you are not using some barrier method like a glove.
Many people who use linseed oil also use solvents during some part of their process, either diluting the paint to keep the first layers lean (low oil content) or as an ingredient in a painting medium, so as to thin out the oil and help it spread. Vincent Desiderio has mentioned thinning the paint in his first layers this way. And I remember that Odd Nerdrum’s go-to painting medium is a mixture containing 1 part linseed oil with 1 part odorless mineral spirits — this is widely used and one of the most basic painting mediums.
It is common practice to cut (dilute) linseed oil with solvent when making a painting medium because linseed oil dries in an incredibly tough film. Contrary to belief, oils do not dry because something evaporates off (like water does when used with watercolor or acrylic). Drying oils go through a chemical reaction with oxygen. When the fatty acids oxidize a chemical bond is formed that links them together into longer lipid chains.
DIFFERENCES BETWEEN OILS
The difference in the strength of these lipid films, drying time, and propensity to darken are all correlated qualities. In other words, the darker the oil, the stronger the film, and faster the drying time. The paler the drying oils have a less durable film and a slower drying time. These include clove, poppy, and safflower oils.
Walnut oil is darker than these oils but paler than linseed oil, and its dried film is less durable than linseed oil. The film made with dried linseed oil is so durable that it has long been used as a material for flooring, especially in parts of the house prone to exceptional abuse such as kitchens – this product is called linoleum. I find the film made by dried walnut oil to be plenty strong, especially as I don’t expect for people to be walking on my paintings or using it as flooring in their kitchens.
You do not want to use an oil for painting that is intended for food use. These oils that are refined for eating purposes are processed to contain things that prevent them from drying. When oils are refined as drying oils, like the ones we use in painting, certain organic compounds that retard drying are removed. So make sure your walnut oil is intended for use in oil painting and not salad dressing.
Some drying oils intended to be used in painting have been processed so that they have partially reacted with oxygen. This includes: sun thickened, stand oil, and boiled linseed oil. I’ve listed these oils from lighter to darker, with each having a quicker drying time to the former and each getting progressively darker.
When you buy oil paint that is ready-made for you in a tube or can, that paint is made with the right amount of oil to bond that amount of pigment to the surface of your support, be it a canvas or panel, etc. If you begin to dilute this paint heavily with turpentine you are not only poisoning yourself but you are also interfering with the ability of the paint to adhere securely to the surface.
Some people use only a little bit of oil as their medium, when working over an underpainting. Jason Yarmosky uses this technique. He paints the underlayer with paint straight from the tube and then uses linseed oil as a medium on top of this layer. This method works only for paintings made in a few layers. It only offers a narrow spectrum of lean to fat from the absorbent ground (wet-sanded acrylic gesso in Jason’s case). The benefit of this technique is that he has eliminated solvent from his practice. But if someone is working in a more “indirect” method — meaning that they will overpaint an indeterminate amount of layers — then other techniques need to be used.
As you paint in more layers, you need to extend the range of these layers from lean to fat, where the first layers have the least amount of oil and each progressive layer is more “fat.” In part 3, I will discuss techniques for expanding the range of oil content in your medium without having to use solvents through a discussion of my approach using walnut oil.