It is well known, from ancient Egypt, that some pigments and colourants can change with time for light effect or chemical attack. Cennino Cennini in the fifteenth century in his book “Il libro dell'arte o trattato della pittura” describes the use of many pigments and their degradation. He was aware of the problems and was able to suggest the answers in the use of pigments on several supports, but he could not understand the physical–chemical reason of the alteration processes. In this study, we point out the aging effects in seven paintings, practically of the same period (1650–1655). We considered in particular green, white and blue pigments of the palette of Valerio Castello. About 150 spots were selected on works painted on four different supports, canvas, wood panel, copper and slate. For each point, several determinations were carried on the pigments and decomposition products, aiming to determine the state of conservation of the paintings, the nature of the pigments, their alteration and if the support can affect the kinetics of degradation.
1. Cataldi Gallo M , Leoncini L, Manzitti C, Sanguineti D. Valerio Castello, 1624-1659, Genio Moderno. Milano: Skira; 2008.
2. Gettens, RJ, Kühn, H, Chase, WT Lead white A Roy eds. Artists’ pigments, a handbook of their history and characteristics, vol 2 Oxford University Press New York 1986 67–81.
3. Martin, E Grounds on canvas 1600–1640 in various European artistic centres 2008 JH Townsend T Doherty G Heydenreich J Ridge eds. Preparation for painting, the artist's choice and its consequences Archetype Publications London 59–67.
4. Gettens, RJ, Feller, R, Chase, WT Vermillion and cinnabar A Roy eds. Artists’ pigments, a handbook of their history and characteristics, vol 2 Oxford University Press New York 1986 159–182.
5. Helvig, K Iron oxide pigments: natural and synthetic 2007 BH Berrie eds. Artists’ pigments, a handbook of their history and characteristics, vol 4 National Gallery of Arts Washington 39–109.
6. Plesters, J Ultramarine blue, natural and artificial 1986 A Roy eds. Artists’ pigments, a handbook of their history and characteristics, vol 2 Oxford University Press New York 37–65.
7. Gettens, RJ, West Fitzhugh, E Azurite and blue verditer 1986 A Roy eds. Artists’ pigments, a handbook of their history and characteristics, vol 2 Oxford University Press New York 23–35.
8. Mühlethaler, B, Thissen, J Smalt 1986 A Roy eds. Artists’ pigments, a handbook of their history and characteristics, vol 2 Oxford University Press New York 113–130.
9. Grissom, CA Green earth 1986 L Robert Feller eds. Artists’ pigments, a handbook of their history and characteristics, vol 1 Cambridge University Press Cambridge 141–167.
10. Kühn, H Verdigris and copper resinate 1986 A Roy eds. Artists’ pigments, a handbook of their history and characteristics, vol 2 Oxford University Press New York 131–182.
11. Smith, GD, Clark, RJH. The role of H2S in pigment blackening. J Cult Herit 2002 3:101–105 .
12. Rinse, J. The vapor pressure, dissociation and transition point of mercury sulphide. Rec Trav Chim. 1928;47:28–35 .
13. Dreyer, RM. Darkening of cinnabar in sunlight. Am Mineralogist. 1938;23:457–460.
14. Weast, RC CRC handbook of chemistry and physics 1998 CRC Press Boca Raton, FL.
15. Scott, DA Copper and bronze in art, corrosion, colorants, conservation 2002 Getty Publications Los Angeles.
16. Lorusso, S, Marabelli, M, Viviano, G La contaminazione ambientale ed il degrado dei materiali di interesse storico-artistico Bulzoni editor Roma 1995.
17. Bianchetti, P, Santopadre, P. Un'alterazione dei pigmenti nei dipinti murali: la trasformazione dell'azzurrite in paratacamite. Boll ICR 2004 8–9:76–86.