This article provides a short review of mineral-based pigments used in paintings with examples drawn from technical studies of selected historic paintings. Pigments such as azurite, natural ultramarine, orpiment, and clay earth pigments have been identified. Some examples will also be given of particular case studies which describe the alteration of selected pigments and consequences of these interactions. The second theme shows how use has been made of such interactions in evaluating the effects of environmental impact on paintings and reference is made to previous studies and the application of paint films as dosimeters. Accelerated ageing and site exposure studies are reported, and results provide information on pigment binder interactions. Dynamic mechanical analysis (DMA) and thermogravimetric analysis (TG) have been used to characterise the behaviour of pigments in binding media and to assist in characterising samples from wall paintings. Reference is also made to the occurrence of iron-oxide based minerals present as corrosion products in archaeological iron objects. Examples are given of objects from two archaeological sites in England, the Anglo-Saxon burial site Sutton Hoo in Suffolk, and the burial site in Wetwang, East Yorkshire. It will be shown that post excavation changes occur in the objects and this information is used to inform preventive conservation of these objects, in storage and in display.
1. Harley, RD. Artists’ pigments c 1600–1835. London: Butterworths Scientific; 1982.
2. Feller, RL, eds. Artists’ pigments. 1 London: Cambridge University Press; 1986.
3. Roy, A, eds. Artists’ pigments. 2 New York: Oxford University Press; 1993.
4. Fitzhugh, EW, eds. Artists’ pigments. 3 New York: Oxford University Press; 1997.
5. Hradil, D, Grygar, T, Hradilova, J, Bezdicka, P. Clay and iron oxide pigments in the history of paintings. Appl Clay Sci. 2003;22:223–236. .
6. Roy, A, Spring, M, Piazotta, C. Raphael’s early work in the National Gallery paintings before Rome. Natl Gallery Tech Bull. 2004;25:62–72.
7. Roy, A. The National Gallery Van Dycks: technique and development. Natl Gallery Tech Bull. 1999;20:5–83.
8. McKim-Smith, G, Anderson-Bergdoll, G, Newman, R. Examining Velázquez. New Haven: Yale University Press; 1988 ISBN 0-300-03615-9.
9. Sheldon L , Woodcock S, Wallert A. Orpiment overlooked: expect the unexpected in 17th century workshop practice. In: Preprints ICOM Committee for Conservation, vol. 1. 14th Triennial Meeting, The Hague, 12–16 September 2005, p. 529.
10. Selwyn L . Overview of archaeological iron: the corrosion problems, key factors affecting treatment, and gaps in current knowledge. In: Proceedings of metal 2004, National Museum of Australia ACT, 4–8 October 2004, p. 294–306.
11. Thickett D . The use of infra-red and Raman spectroscopies for iron corrosion products. In; Postprints 6th Infrared Users’ Group, Florence, Prato, Padua 2005, p. 86–93.
12. Watkinson, D, Lewis, MT. Desiccated storage of chloride-contaminated archaeaological iron objects. Stud Conserv. 2005;50:241–252.
13. Turgoose, S. Post excavation changes in iron antiquities. Stud Conserv. 1982;27:92–101. .
14. Cohen, NS, Odlyha, M, Campana, R, Foster, GM. Dosimetry of Paintings:determination of the degree of chemical change in museum exposed test paintings(lead white tempera) by thermal analysis and infrared spectroscopy. Thermochim Acta. 2000;365:45–52. .
15. Odlyha, M, Cohen, NS, Foster, GM, West, RM. Dosimetry of paintings: determination of the degree of chemical change in museum exposed test paintings (azurite tempera) by thermal and spectroscopic analysis. Thermochim Acta. 2000;365:53–65. .
16. van den Brink O . Molecular changes in egg tempera paint dosimeters as tools to monitor the museum environment. Ph.D thesis, University of Amsterdam, 2001. http://www.amolf.nl/.
17. Musumarrra, G, Fichera, M. Chemometrics and cultural heritage. Chemom Intell Lab Syst. 1998;44:363–372. .
18. Colombini, MP, Modugno, F, Giacomelli, A. Two procedures for suppressing interference from inorganic pigments in the analysis by gas chromatography-mass spectrometry of proteinaceous binders in paintings. J Chromatogr A. 1999;846:101–111. .
19. Odlyha, M. Introduction to the preservation of cultural heritage. J Therm Anal Calorim. 2011;104:399–403. .