Historically, several solvents have been and continue to be used in conservation studios for different kinds of procedures, such as varnish cleaning, in painting removal, dilution for commercial pigments used in retouching, among others. The most common solvents used in these procedures are based on aliphatic and aromatic hydrocarbons, the latter having the most harmful health effects due to their high toxicity. A solvent's ability to remove a given compound by dissolving it depends mostly on its polarity. In order to achieve the appropriate polarity, both solvent solutions types (aliphatic and aromatic) and their derivatives are used depending on the substance to be dissolved. There are currently certain products and solvent mixes (Shellsol, Arosol, White Spirit) sold around the world that replace, in some cases, the more toxic kind of solvents. In Latin America, however, they are either unavailable or sold at very high prices. Therefore, many conservators still use solutions that are high in toxic solvents (toluene, xylene, turpentine), as they are the widest-known and most easily available in the market. The aim of this research is to replace the more toxic common solvents with organic solvents dissolutions that are far less toxic yet equally effective and easily accessible in the local market. Solutions were developed based on paraffin and cyclic saturated open-chain hydrocarbons that are less toxic than aromatic and high-toxicity, non-aromatic ones commonly used. Paraffin hydrocarbons were chosen for study based on their polarity as well as their maximum acceptable concentrations (MAC) as per international standards. The dilution of commercial pigments for retouching and varnish removal were used as reference, being common practices in conservation studios and both requiring the use of solvents. Tests were conducted using different varnishes and commercial pigments for retouching to assess the effectiveness of the solutions and draw conclusions, placing particular emphasis on analyzing both natural and synthetic resins. Tests reveal that, even though no mix proved to be effective in all cases, simple paraffin hydrocarbon mixes and minimum aromatic hydrocarbon concentrations can lead to effective solutions in both procedures under analysis, with a significant reduction of toxicity posing no risks to the works of art being restored. We also demonstrated that the commercial solvents analyzed are not reliable when it comes to reducing toxicity, as manufacturers fail to reveal their specific composition in the Product Safety Data Sheets and actual percentage of toxic solvents used in their mixes. Using lower toxicity solvents is not only beneficial to the conservator but also to the environment, which is why it is important to find affordable and easily available substitutes to eliminate such toxic substances from conservation studios.
Paintings Conservator, Cultural Heritage Recovery Coordination. Ministry of Treasury of Argentina.
As an art conservator specializing in paintings, Luciana has been working in different restoration studios and as an independent conservator in major museums in Buenos Aires, including the world-renowned Latin American Art Museum of Buenos Aires (MALBA) and the Buenos Aires Museum... Read More →