Solvents have long been a problem in the world of oil painting.  A solvent, or paint thinner, is used to thin the paint and clean brushes.  Thinning  is an important part of painting with oil-based paint.  The tendency is to paint thin to thick. This means applying a thin first layer of paint as the composition is being worked out. This thin layer of paint becomes your guide with general colors, shapes and edges.  Then, as you build up paint on the canvas in the subsequent layers, it is easy to correct any edges, shapes and colors because the first layer does not have bumps and ridges created by thick paint.

A thin paint can also be used for effect.  When I want my paint to drip, I load up my brush with thinner, not oil. The thin paint will roll or seep down the canvas, which can be an interesting contrast to the more detailed painting that happens in subsequent layers. Of course, solvent is also used for cleaning brushes. When cleaning, it is best to remove as much paint as possible by swishing the brush in a can or jar of thinner before washing with brush soap. Solvents are also reusable. When you are done painting for the day, you let the solvent sit in its container.  The pigment from the paint will slowly settle to the bottom of the container and then you can pour off the clean solvent that has risen to the top to reuse it.

The harmful part of thinners are the vapors. They can be toxic and irritating to the skin, nostrils and lungs. Over the centuries, artists have used a very pungent and caustic paint thinner called turpentine. Turpentine is derived from pine trees but is toxic and flammable. It is also hard to spend a long time around the odor because it is so strong.  In 1924, Mineral Spirits, a petroleum distillate, was created for the dry cleaning industry.  By the 1950's and 1960's, the dry cleaning industry had moved on to other solvents, but mineral spirits began to be used in the home and for thinning oil-based paints.  Mineral spirits is less flammable and pungent than turpentine, but still had its issues. Mineral spirits, in large doses or consistent exposure over time, can be toxic. Thou its smell was not as bad as turpentine, it still had a strong chemical smell. It wasn't until the 1990's that an odorless version of mineral spirits was created. This was a great improvement to the painting experience. Today it is hard to imagine the images in documentaries from the fifties and sixties of artists who were using open coffee cans full of pungent flammable paint thinner and smoking cigarettes while painting. From the linings of their nostrils to the capillaries in their lungs their respiratory system were under attack.

Although odorless solvents were a great improvement, the thinner was still made from petroleum and the vapors can still be toxic, irritating and combustible.  Mineral spirits is refined from petroleum.  Petroleum refineries are a major source of air and water pollution for employees and people who live near them. The chemicals in and around refineries have been proven to cause cancer, reproductive harm, and breathing problems such as asthma and emphysema, as well as causing headaches, nausea, dizziness, and stress.

In my efforts to move to more earth-friendly products, I have discovered a plant-based solvent called Eco-Solve by Natural Earth Paint Co.  According to their website, Eco-Solve is "the most eco-friendly, plant-based, professional paint thinner on the market. Representing a major breakthrough in eco-art technology, Eco-Solve can be used to thin paint, clean brushes, and restore old, dried brushes, providing earth and health-conscious professional artists with a safe alternative to toxic conventional paint thinners."  Eco-Solve is made from processed soy bean oil and is 100% natural.  Eco-Solve has been tested by professional toxicologists to be non-toxic and it does not emit harmful vapors, irritate the skin or pollute the soil or waterways. It is also archival, professional artist-quality, and non-yellowing. It is extremely effective for cleaning brushes and tools. As an added bonus, it is safe and legal for air travel (unlike conventional solvents) and the packaging is 100% post-consumer recycled aluminum or glass bottles.

What a website says is one thing, but the proof is in the pudding, as they say. I have been working with Eco-Solve for a little while now and have found it to be an excellent paint thinner.  It performs as well as odorless mineral spirits. It thins oil paint down for consistent washes and drip effects. It also cleans brushes well. I have had no issues with cleaning brushes with Eco-Solve.  Even a brush with some hardened paint was made like new after using Eco-Solve and a good brush soap. Of course, we all clean our brushes right after painting, not letting them sit around to dry... right?

Are there any negatives to Eco-Solve? The website mentions that it might take paints mixed with Eco-Solve slightly longer to dry than conventional turpentine/mineral spirits. This has not been an issue for me as I am working on several paintings at once and simply paint a different canvas if one is still too wet. Yet, even a day after creating thin washes with Eco-Solve I found the paint to be dry. I have not seen much difference on thicker layers of paint whether using odorless mineral spirits or Eco-Solve.

Eco-Solve does have a smell. The website describes it as a subtle fruity licorice scent. I agree with that description, but it really struck me at first because I had used odorless mineral spirits for so long.  But after only a couple sessions I no longer even notice the smell.

The cost is the only aspect that might hold people back. It can be as much as three times the cost of Gamsol or other odorless mineral spirits.  Of course, my thoughts on environmental issues is that if we don't pay now, we actually pay more later - sometimes with our lives. But, because Eco-Solve evaporates so slowly it actually lasts longer in its palette container. Thus, it has a longer life and there is less need to replenish it as often as other solvents, which helps with the cost factor.  Evaporation rate and flammability are related. The more flammable the solvent, the faster it evaporates and vice-versa. Eco-Solve is considered non-flammable, so it evaporates slowly and paint mixed with Eco-Solve, as stated, may dry a little more slowly. I am still working to determine just how much this slower evaporation rate effects the overall cost and if it ends up being more comparable to odorless mineral spirits if there is less of a need to replenish it on your palette. I will share more on this as the data comes in. 

I highly recommend Eco-Solve for oil painting. Especially for those that have had skin irritation from petroleum-based thinners. I have been around so many solvents over the years that I feel my breathing has been slightly effected. It will take much longer to see if using Eco-Solve will help in that area.

Let me know what products you have used and how they have effected you.