Article: Studio Safety - Sansodor vs 'Regular' Solvents

All solvents used with oil colours are “volatile,” a word that, before going any further, is worth defining relative to your art materials. In the world of chemistry, volatile means that some substances like to “reach for the sky,” and would prefer to go through life as a vapor. Some of these substances are so volatile, or so eager to make it to the vapor state that, if given the chance, they’ll make a strong statement about the transition. Like nitroglycerin. Other substances are more easygoing about the change. For painters or anyone else using solvents on a regular basis, the more relaxed about the change, the better. 

When talking about solvents for oils, two characteristics are highly desirable:

1. The solvent should be fully volatile, meaning that, when it leaves the paint film, it leaves nothing behind. Some solvents, particularly hardware grade turpentine or mineral spirits, as well as many of the recently introduced citrus-based solvents for oils, are not fully volatile and leave all kinds of impurities and detritus behind to sully your precious paint film.

2. The solvent should be low in aromatic content. Aromatics are the constituents that, when inhaled, can cause health problems (hence the label warnings on solvents, some of our mediums, and Griffin Alkyd Fast Drying Oil Colour about nausea and headache).

At Winsor & Newton we have gone to great lengths to identify and make use of solvents that best meet those two criteria. And that’s what we have in Sansodor, a fully volatile solvent, with very low aromatic content. 

A measure of how much aromatic content is within the solvent, and how much a painter can be exposed to without significant risk, is quantified as “TLV,” threshold limit value or “PEL,” permissible exposure limit. Values for TLV and PEL are generally equivalent and refer only to inhalation toxicity, measuring how much of the solvent can be present in the immediate environment without risk. Artists can use these values as a guideline to studio safety. The higher the measured value, the better.

Turpentine, the strongest and arguably the most noxious common solvent for painters, has a low TLV of 100 parts-per-million (ppm), meaning that when there’s 100ppm of turp in the painter’s surrounding atmosphere, there’s a significant likelihood of effect on the individual, from headache, to nausea, to allergic reaction, and more. Mineral spirits, or white spirits as it is called in Europe, is similar.

Common “odorless” thinners from the hardware store have a TLV of 200ppm, higher than turpentine, but still lower than some other solvents developed for fine art use. Highest of all, and tied with a competitor’s product, is Winsor & Newton Sansodor, at 300ppm. However, Sansodor has a higher flash point than the other product, meaning that it doesn’t vaporize to form an ignitable mixture in air as soon as the other product will. Bottom line?  When using traditional oils or alkyd colours, there’s virtually no way to avoid the use of solvents, and appropriate care should always be taken by the artist. That said, there’s no better solvent choice on the market than Sansodor.

As with any solvent, however, be sure to follow safe studio practices.

Finally, any artist looking to completely eliminate the use of solvents, but still desiring the unique qualities of oil colours, should consider Artisan Water Mixable Oil Colour.