Colour measurements for monitoring the conservation of contemporary artworks

TLDR: In this article, the data acquired by using Fibre Optic Reflectance Spectroscopy (FORS) and spectrocolorimetry on the mural Tuttomondo (1989) painted by Keith Haring (1958-1990) on the wall of the Church of Sant'Antonio Abate in Pisa (Italy) is reported.

Abstract: In this paper the data acquired by using Fibre Optic Reflectance Spectroscopy (FORS) and spectrocolorimetry on the mural Tuttomondo (1989) painted by Keith Haring (1958-1990) on the wall of the Church of Sant'Antonio Abate in Pisa (Italy) will be reported. Tuttomondo is one of a few extant Haring large murals worldwide. Although it was in a relatively good state of conservation, alterations and fading of the colours, yellowing and darkening of the white background, and losses in the black lines were observed. A diagnostic survey was begun in September 2011 to evaluate the state of conservation of the mural in order to support the conservation intervention which was focused on cleaning and the subsequent consolidation of the mural painting. The FORS data recorded on several spots (about 1.5-mm in diameter) of the mural before any conservation procedures provided useful information on the composition of the acrylic paints supplied to the artist by Caparol Italy GmbH & Co. In regards to the yellowing and darkening of the white background, as well as the fading of the colours, cleaning tests were carried out, using various materials (e.g. hard erasers, deionised water, wishab, and cleaning emulsions). For some of these tests it was decided to use spectrocolorimetres to monitor and document the colour variations caused by each cleaning test on selected areas both before and after the cleaning process. The colorimetric data supported the choice of the final cleaning procedure, which, to a great extent, enabled the recovery of the vivid original colours. The colorimetric measurements will be used to monitor the state of conservation of the mural on a regular basis.