PATRIMOINE

Couleurs du Sud

Icon of the Cretan school conserved in the Benaki Museum (Athens) and investigated by the MedColour project. In-depth investigation has identified the organic and inorganic pigments of the reds of the different paint strata.© Benaki Museum, Athens – Photo Conservation department
Icon of the Cretan school conserved in the Benaki Museum (Athens) and investigated by the MedColour project. In-depth investigation has identified the organic and inorganic pigments of the reds of the different paint strata.
© Benaki Museum, Athens – Photo Conservation department

Analysing the natural pigments used by artists and craftsmen in the Mediterranean basin throughout history. Reproducing them industrially for use by restorers and creative artists today. Spotlight on the MedColour European project.

Ochres that pass from bright yellow to deep orange, reds that can darken to near-black, inimitable blues… Since antiquity, the works and objects of art from the Mediterranean heritage have shared a common colour palette.

These tonalities are found equally in painting, textiles and manuscripts from the Middle East to southern Europe simply because the artists and craftsmen of this part of the world used the same pigments, taken from plants, minerals insects and shellfish, even if our knowledge of the ‘colour routes’ they took over time is imperfect. ‘From the 19th century onwards, synthetic colouring agents took over from traditional techniques based on natural pigments, which then fell into oblivion. If we want to restore ancient works, we need therefore to identify and analyse these pigments. Rediscovering them would enable us to avoid the clumsy restorations of the previous century, and maintain our entire Mediterranean heritage with proper respect for its specificity. This is the objective of MedColour and for this we are making use of the most advanced physical and chemical technologies,’ explains chemist and project coordinator Ioannis Karapanagiotis.

High tech in the service of art

More than 130 works from different periods and different techniques, all of irrefutable provenance and dating, were the subject of this research. The evidence is as varied as little rugs of the Seljuk period at the Museum of Istanbul (Turkish and Islamic art), a tunic (sakkos) of Emperor Ioannis Tsimiskis (Iveron monastery on Mount Athos in Greece) or 13 icons from the 15th to the 17th century belonging to the Cretan school. The latter in particular are enabling us to study the evolution of the reds, to identify the organic and inorganic colours, and to see whether novel pigments were introduced after the discovery of the New World.

Microscopic samples have been used to examine the structure of different layers of paint, using a combination of several sophisticated physical and chemical methods, such as Raman spectroscopy or High Performance Liquid Chromatography (HPLC) coupled to a photodiode detector(1). This new knowledge makes it possible, for example, to restore works of art knowing exactly what pigments were used in a particular layer of varnish and to clean each stratum with appropriate solvents. Additionally, manufacturing wool or silk in the traditional manner will help carpet restorers to use colours that are close to the original and far more resistant to light than industrial products.

To present the concrete aspect of their approach, the MedColour partners organised various workshops at the Sidi Mohamed Ben Abdellah university at Fez (Morocco) in November 2008. ‘We wanted first of all to inform SMEs and organisations in the craft sector of the possibility of creating new natural colouring agents, manufactured industrially, but incorporating traditional recipes,’ says Rachid Benslimane, of the University of Fez. ‘It was also an opportunity to disseminate to researchers and specialists the latest results of our work on new methods of diagnosis and identification of natural colouring agents in objects of art and the technologies for producing and characterising these colorants.’ The dissemination of this knowledge is another important objective of the MedColour partners. They are currently developing a database that will provide information on conservation strategies for the Mediterranean heritage.

Christine Rugemer

  1. Raman spectroscopy is a non-destructive method for characterising the molecular composition and structure of a material. HPLC, or high performance liquid chromatography, is an analytical separation technique based on the hydrophobicity of the molecules of a compound. A photodiode is a semiconductor component that can detect radiation from the optical field and convert it into an electrical signal.
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