Colour measurements for the characterisation and monitoring of contemporary works of art

Abstract

In contemporary art, the expression of the artist's creative message is often considered more important than the preservation of the artwork itself. Considering wall paintings preserved outdoors, it is evident that these tend to lose their original aesthetic characteristics over time, particularly their colour. It is therefore very important, for documentary and conservation purposes, to measure the colorimetric values of such artefacts. Indeed, colour measurements make it possible to follow the conservation procedures to which the work is subjected, to check the colour results of retouching or other restoration processes and to monitor the behaviour of the work itself during temporary and permanent exhibitions. For this reason, any conservation study and/or intervention should include a preliminary campaign of diagnostic investigations. The spectroscopic and colorimetric investigations conducted as part of the conservation project of Keith Haring's Tuttomondo mural made it possible to: identify the pigments used by the artist; check the chromaticity before, during and after the cleaning treatment; check any colour variations following the protective treatment; and create a colour mapping after the treatment to provide reference colorimetric values to be used during the work's maintenance processes. The diagnostic campaign confirmed the effectiveness of the cleaning treatment that induced significant colour changes throughout the surface. All colours, which were faded after twenty years of environmental exposure, appear more saturated and bright after the conservation treatment. The protective treatment, on the other hand, did not induce colour changes on the surface, except for the red area, confirming the good transparency characteristic of the conservation product. One year after the conservative treatment, the mural did not change significantly, confirming the effectiveness of the chosen treatment.