Scientists at CSIC and at the University of Bologna have developed a method for the removal of calcium carbonate crystals on surface of cultural heritage and artworks by means of a light source at a specific wavelength. Industrial partners are being sought to collaborate through a patent licence agreement.

This methodology It can be used to clean virtually any type of work and material: paintings, frescoes, engravings, mosaics, sculptures or monuments, among others.Cultural heritage artworks are permanently exposed to environmental conditions that can drive to deterioration due to instability of the materials, water-soluble salts, humidity, temperature conditions, atmospheric pollutants and biological action.

One of the most significant consequences is the unwanted formation of calcium carbonate crystals, usually at very small spots in artworks. To prevent  deterioration of the piece of art it is necessary to remove these carbonate calcium crystals. This is usually possible with solvents or solvent mixtures, which are selective cleaning methods but, often, toxic.

The procedure developed by the CSIC's Instituto Andaluz de Ciencia de la Tierra and the University of Bologna allows crystallized calcium carbonate to be dissolved in a precise and safe way. It can be used to clean virtually any type of work and material: paintings, frescoes, engravings, mosaics, sculptures or monuments, among others.

Since calcium carbonate dissolves under a pH lower than 4 conditions, the method combines a treatment to lower the pH in a controlled way with the irradiation afterwards of the calcium carbonate crystals with a light source at a specific wavelength. The source of light can be an incandescent lamp, a gas discharge lamp or a light-emitting diode. To lower the pH, it is used a mixture of a photo acid generator and a sensitizer.

This method represents a significant improvement in the cleaning process because it allows the irradiation wavelength range to be extended, allowing the use of visible light (400 nm- 700 nm), and reduces irradiation time (from 5 to 15 minutes).

The CSIC has applied for a European patent with the possibility of international extension and is currently looking for companies interested in the development and commercial exploitation of the technology.

Contact:

José Ramón Domínguez Solís
Deputy Vice-Presidency for
Knowledge Transfer - CSIC
Tel.: +34 954232349 ext. 540030
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