Many oil painters are interested in eliminating harmful solvents from their painting methods, or reducing their exposure to the most harmful, although commonly used, solvents. For those painters, there are alternatives.
The simplest is to choose water-miscible oil paints (paints that use water as both a solvent and a cleaner). In these paints, the oil binder has been chemically altered to accept water as a means of dissolving particles.
However, some professional artists struggle with certain drawbacks: the limited, albeit growing, color palette of about 80 colors, and the grainy, sometimes chalky, consistency of the paint. This is not to say professionals can’t find ways to make these paints work, but sometimes the best solutions are removing the chemicals from your process, not adding more.
In this article, we will discuss direct painting, dilutants and alkyd mediums.
Solvents versus Dilutants
It is important to note the difference between a solvent and a dilutant, as well as the differences in the application of each. Solvents dissolve the pigments in paint. In watercolors, gouache and water-miscible oil paints, water acts as the solvent. In regular oil paint, one must use turpentine, mineral spirits or odorless mineral spirits because of the oil binder. Alcohol-based mediums, such as alkyds, may technically be solvents, though the solvent action and toxicity are minimal.
Dilutants, on the other hand, merely increase the fluidity of the paint. Linseed or walnut oil are two of the most popular binders in oil paint, and can be added as dilutants in solvent-free oil painting. However, adding too much oil can cause wrinkling. Use only the smallest amounts of oil, and be sure to always follow the fat-over-lean rule (a gradual increase in the amount of oil in each progressive layer). Solvent-free painters using dilutants must apply paint in thin layers, using virtually no oil in the bottom layer of their paint. Otherwise, those layers that dry slower may crack the faster-drying layers.
Was Rembrandt Solvent-Free?
While there are conservators arguing both sides of this question vehemently, nearly all agree that the painters of the past used far less solvents than we use today. Solvents, in the form of distilled turpentine, began to gain popularity among painters in the 16th and 17th centuries.
The switch to painting with solvents is due in part to the way paint is manufactured today. Currently, oil paint is squeezed from tubes as a thick paste that requires thinning through the addition of either a solvent or a dilutant, or both. Centuries ago, oil paint had a different consistency. Because hand-ground paint is generally much thinner, it needs far less additions to make it usable.
Although he is most often remembered for his biographies of Renaissance artists, Italian painter, architect and writer Giorgio Vasari (1511 – 1574) was a master artist that conservators are fairly confident worked without solvents. In his book, The Lives of the Artists, first published in 1550, Vasari says that he “proceeds to grind the colours with walnut or linseed oil, though walnut oil is better because it yellows less with time. When they are ground with these oils which is their tempera (medium), nothing else is needed so far as the colors are concerned but to lay them on with a brush.” From this statement, we can conclude that Vasari felt that solvents were unnecessary, at least for the manner in which he painted.
Going Alla Prima
Solvent-Free Clean Up Tips
In place of solvents, oil painters can use virtually any oil to clean their brushes: linseed, walnut, safflower, poppy, etc. Wipe the excess paint from your brush with a paper towel so you get most of the pigment out, remove the remaining pigment with oil, and then wash the brush out with soap and water. You won’t be flushing any chemicals down the drain, and you’ll be saving the lives of your brushes. Keep in mind that oils are flammable, some more than others, so make sure you dispose of them in a proper manner.
Also, you can re-use the oil by keeping it in a jar, "rinsing" excess pigment out in the jar, and then allowing the sludge to settle - this takes about a day or two. You can then pour the clean oil into a new jar, and simply dispose of the sludge at a waste disposal facility.
The most straightforward way for an oil painter to go completely solvent-free is to paint alla prima, also known as the all-at-once or direct painting technique. However, if finishing a painting all in one sitting isn’t your style, or if you prefer glazing, you may require a dilutant to allow for thinner applications.
Using Walnut Oil Products
Paint manufacturer M. Graham and Company (www.MGraham.com) has been advocating solvent-free painting since it’s inception in the 1970s. The company uses walnut oil as the binder for its oil paint. Company founders Art and Diana Graham say their paint is conducive to thinner applications, without the addition of solvents, because walnut oil has a lower viscosity than linseed oil. They sell pure walnut oil, as well, which can be used a medium for the paints as necessary, but say putting pressure on the brush is really the key to getting thinner glazes of oil paint.
“We’ll get communications from artists that think this is something new, but what we’re advocating is nothing different from what artists in the 15th and 16th centuries were doing,” says Art Graham.
The company also sells a walnut alkyd medium, which acts as a drying oil and increases fluidity. Graham is quick to point out, however, that artists cannot use the walnut oil or alkyd medium as direct substitutes for solvents.
“This is a different way of painting, not a substitute for solvents,” says Graham. “People will get in contact with us and ask how you can get the same look as a turpentine or mineral spirit, but you can’t simply thin the color and douse it on the canvas.”
Using Linseed Oil Products
Creating Your Underpainting
Beginning solvent-free oil painters may struggle with creating their underpainting, or blocking out shapes, while following solvent-free rules. After all, you can't simply add a bunch of oil to create a thin glaze for the underpainting, as it probably will not be archival. One solution is to create the underpainting using a water-based paint (remember, you can paint oil paints over water-based paints, but you can never do the reverse). You can also use a regressive technique, where you apply a thin layer of oil paint by applying pressure to the brush, and then wipe away the excess with a rag or paper towel.
While walnut oil may be more fluid, there are many solvent-free painters using linseed oil paint instead.
Stephen Knudsen, professor of painting, color theory and design at Savannah College of Art and Design, in Savannah, Georgia, uses linseed oil-based paint and linseed oil as a dilutant. He also requires that students taking his classes do the same.
“I’ve been almost entirely solvent-free for about 20 years,” he says. “Even as a student, I just didn’t like using the solvents. My original background was in chemistry and biology. You start to understand what solvents are going to do to you long-term. I found that, even as a student, I could do just about anything the professor was asking me to do without the solvent.
“Painters often like to work with thinner passages of paint and get thicker. I found that I could work from lean to fat; it’s just that I usually work in a little bit fatter than most people would start. I take the paint out of the tube, add a little extra oil than most people, and use pressure (on the brush) to get the paint thin. I never add more than 50 percent oil to the paint coming out of the tube; it’s not archival."
Shine or No Shine
Some artists who are wary of solvent-free painting voice that they are concerned that using an oil or alkyd in place of a solvent will create too much of a glossy, oil-rich feel to the work.
Knudsen, an expert in color theory, explains that an artist’s choice of color has more to do with the way the painting appears because some inorganic pigments are opaque, while organic pigments are translucent.
“That look, whether you want it to be more shiny, glossy or satin, is better controlled with pigment choices,” he says. “Inorganic pigments have a higher refractive index, meaning light gets bent more as it passes through them. Organics have the lower refractive index. The inorganics do not require as much oil to suspend them. If you squeeze lead white out of the tube, which is actually an inorganic pigment, there’s not as much oil in it (in fact, it is one of the most matte coming out of the tube since it does require much oil to suspend it, especially in the form of Cremintz White); it looks matte. Cadmium paints also will be more matte. Ultramarine is an exception, as it’s inorganic and highly translucent. The inorganic tend to have more body to them, so you can create a painting that is more matte. On the other hand, an organic pigment like Quinacridone requires much more oil to suspend it and will be more glossy.”
Knudsen suggests that you take a look at the main ingredient listed on your paint tubes. Google these individual pigments (for example, titanium dioxide), to see what the molecular structure is. If the first thing listed in the molecular formula is carbon, (in other words if carbon is the main molecular component), then it’s an organic substance. Again most inorganic pigments are opaque and create a more matte look, while most organic pigments are transluscent and create a shinier look).
Graham agrees that color choice plays a big part in the effects that a solvent-free painting creates. “You should not try to glaze with an opaque color,” he says. “A glaze is really a thin application of a transparent color as opposed to thinning out an opaque color. An interesting by product of doing this is that you get a huge amount of resonance to the painting itself. When you use a solvent as a dilutent, it flattens outs. When you don’t, the work contains a high degree of brilliance, it’s recognizable to the eye.”
However, he also advises artists to take it for what it’s worth.
“Surface reflectance is what it is,” he says. “Some people like it, some people don’t. I think the best thing people can do is probably rely upon final varnishes to achieve the surface reflectance they want, rather than try to make it with the paint.”
Graham admits, however, that high-quality varnishes do need to be solvent-based. The good news is, since that’s a much shorter process, you can take the piece outside or to a properly ventilated space before applying it.
Safer Solvent Options
For artists hesitant to completely eliminate solvents, there are a number of other alkyd or alkyd resin mediums that can be added to linseed oil paints with ease, including Galkyd, produced by Gamblin Artist Colors. These products adjust drying times, as well as increase fluidity. Keep in mind that Galkyd does use Gamblin’s Odorless Mineral Spirits (Gamsol) as an ingredient, and painters can add up to 50 percent additional Gamsol to adjust the viscosity of Galkyd. Using an odorless mineral spirit and alkyd resin serves as a replacement for stand oil and turpentine formulas, without the extreme toxicity of the turpentine. As far as odorless mineral spirits go, Gamsol poses the least amount of danger to a user, with a flash point of 145 degrees (turpentine has a flash point of 90 degrees and other odorless mineral spirits a flash point of 125 degrees), and has a much slower rate of evaporation than either turpentine or other odorless mineral spirits. Find out more at www.gamblincolors.com.
Regardless of which technique you employ, the adjustments you make to your painting methods can virtually eliminate toxic fumes and solvents from your studio. It may difficult to embrace something new, but for the sake of preserving your health and the health of your family, change may be worth exploring. AC
An artist and writer, Kim Hall is the former Editor of Professional Artist. She holds a B.A. in Art from the University of Central Florida and an M.A. in Arts Administration from Savannah College of Art and Design. Kim can be reached at firstname.lastname@example.org.