Historical Painting Techniques, Materials, and Studio Practice

to contain sufficient lead to fulfill the requirements of the above formula or
for a heavy lead glass.
In Venice, there is blue enamel opacified with arsenic 250 years before it is
known to have been used to opacifY glass. In Basohli two centuries later, a
pigment previously unknown in India was used and in three cases; it is very
similar to the Venetian enamel. The enamels are of exactly the same period
as when smalt first appears in European paintings, but in no example yet
identified does it contain arsenic and bismuth. Do we have two completely
independent discoveries, or were both importing enamel fr it from some Middle
Eastern source that was using arsenic as an opacifier earlier than the
Venetians? The author has been unable to find any analyses which may hold
the answer to the sources of Persian or Middle Eastern enamels of the relevant
period.
As a footnote, smalt contammg a trace of bismuth was found on a south
German oil painting (ca. 1400-1500 C.E.) in the collection of the Courtauld
Institute of Art (46). In this case, it seems likely that the cobalt oxide colorant
was obtained from the residue of the smelting of bismuth (as described previously),
and that it is an accidental constituent.
Conclusion
Trade, industry, and art are ancient, ubiquitous, and international. This paper
has endeavored to show that "new" pigments can still be found in unexpected
places. The connections and coincidences that become apparent to the scientist
through laboratory testing indicate historical trade and industrial developments,
and may sometimes ultimately depend on the craftsperson who
experiments with new materials. Our ability to understand these connections
and coincidences requires knowledge of metalworking, ceramics, glass, and
enamels to explain these connections and coincidences both in time and
place.
Notes
1. Watson, 0. 1994. Personal communication. Ceramics and Glass Collection, Victoria
& Albert Museum, London SW7 2RL.
2. Turner, W E. S., and H. P. Rooksby, 1959. A study of the opalising agents in
ancient opal glasses throughout three thousand four hundred years. Glastechnische
Berichte 32K (VIII): 17-28.
3. Neri, A. 1612. L'Arte Vetraria. Florence.
4. Turner, op. cit.
5. Darrah, J. A. 1992. Venetian and Facon de Venise glass. Unpublished analyses.
London: Victoria & Albert Museum.
6. Merrifield, M. P. 1849. Original treatises Jrom the XIIth to the XVIIlth centuries on
the arts oj painting. John Murray, London, 200-5.
7. Merrifield, op. cit., 704-5.
8. Merrifield, op. cit., cliii.
9. Harley, R. 1982. Artist's pigments c. 160(}-1835. 2nd ed., Butterworth Scientific,
172-73.
10. Harley, op. cit.
11. Ibid.
12. Ibid.
13. Tingry, 1830. The Painter's and Colourman's Complete Guide. 3rd ed. London:
Sherwood, Gilbert and Piper, 45.
14. Linton, W 1852. Ancient and Modem Colours Jrom the Earliest Periods to the Present
Time. Longman, Green, Brown and Longman. London, 55.
15. Field, G. 1890. The Rudiments oj Colours and Colouring. Strahan and Co. London,
63.
16. Mayer, R. 1951. The Artists Handbook oj Materials and Techniques. London: Faber,
69.
17. Isacco, E., and J. A. Darrah. 1993. The ultraviolet and infrared method of analysis.
A scientific approach to the study of Indian miniatures. Artibus Asiae, LIII (3/
4):470-91.
18. Merrifield, op. cit., 650-5 1, 700.
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Historical Painting Techniques, Materials, and Studio Practice