Historical Painting Techniques, Materials, and Studio Practice

process described by Cennini for gesso sottile as furnishing the best ground
for gilding (29). In fact, Cennini describes in Chapter CXVIII how certain
panels can be grounded only with gesso sottile.
Conclusion
Finally, returning to the meaning of the giesso volteriano in Cennini's text,
we presume that the material must have been calcium sulfate dihydrate
burned at 300-650 °c, thus forming soluble anhydrite, which was used fo r
the gesso grosso. The preparation of the gesso sottile would be a process of
changing the chemical composition, altering the texture, and washing.
The author does not agree with the point of view put forward by E. Martin,
et al. that Cennini did not know whether the giesso volteriano he discussed
was unburned gypsum directly from the quarries of Volterra or if it was
processed by being burned (30). Cennini must have had a good understanding
of these materials. That we do not understand the exact meaning of his words
600 years later is another matter. In his own time and geographical sphere, it
was most likely very well understood, at least by other craftspersons.
Acknowledgments
It was extremely difficult to obtain raw calcium sulfate dihydrate in Denmark. I am
very much indebted to the following persons who made the practical experiments
possible: V Meyer (Building Materials, Kalkbr;enderihavnsgade 20, 2100 Copenhagen),
who readily took the trouble to import unburned gypsum for my research
purposes, and to Niels Erik Jensen (CTO, Aiborg Portland, 9220 Aiborg 0st), who
demonstrated a keen interest and readiness to help with this project by providing me
with raw gypsum in various forms. I wish to thank my colleague, chemist Mads Chr.
Christensen (School of Conservation, Copenhagen) fo r his help in carrying out the
analyses, and for fruitful discussions. My colleague, geologist Nicoline Kalsbeek,
(School of Conservation), has kindly furnished me with information from the Cambridge
Structural Database. Finally, I wish to thank Professor Bo Ossian Lindberg
(Institutionen fOr Konstvetenskap, University of Lund, Sweden) for reading and commenting
on the text.
Notes
1. Cennini, C. 1960. The Craftsman's Handbook: II libro de/l'arte. Translated by D. V
Thompson, Jr.. New Yo rk, Dover Reprint (Yale University Press, 1933).
2. Cennini, C. Boken om nullarkonsten. Oversiittning och notkommentar av Ossian Lindberg.
Unpublished manuscript provided by Professor Lindberg. Part of the text
has been published in Lindberg, B. 0. 1991. Antologi om milleriteknik. Lund: Institutionen
fo r Konstvetenskap, Lunds Universitet. As shown by Lindberg, the
Codex Laurentianus (Florence, Biblioteca Laurentiana, MS 78 P 23) must be considered
closest to the lost original manuscript. The Codex Riccardianus (Florence,
Biblioteca Riccardiana, MS 2190), however, is our only source for several passages
which are missing in the Laurentianus text. Therefore, Lindberg based his edition
on both the Laurentianus and the Riccardianus codices, as Thompson also did.
For the discussion of the surviving transcripts of Cennini's text and the various
editions and translations, see Lindberg, B. 0. 1991. Cennino Cennini: den obnde
masteren. In Miliningens anatomi. Exhibition catalogue. Kuituren, Lund, 39-48.
3. Oddy, W A. 1981. Gilding through the ages: An outline history of the process
in the Old World. Gold Bulletin and Gold Patent Digest (14): 75-79, in particular
page 77. See also, Gilded wood: conservation and history. 1991. Gilding Conservation
Symposium, Philadelphia Museum oj Art. Madison, Sound View Press, 34.
4. Berger, E. 1973. Quellen und Technik der Fresko-, Oel-und Temperamalerei des Mittelalters.
Liechtenstein Sandig reprint (Munich 1912), 13.
5. The medieval sources mentioning the preparation of grounds also mention (animal)
glue as the medium. The only exception, to my knowledge, is the fifteenthcentury
Bolognese manuscript, which mentions a ground that apparently has no
medium but depends on the setting with water of the hernihydrite. See Merrifield,
M. P 1849. Segreti per colori, Original treatises on the arts oj painting,
Vol. II. London, John Murray, 595.
6. Martin, E., N. Sonoda, and A. R. Duval. 1992. Contribution a l'etude des preparations
blanches des tableaux italiens sur bois. Studies in Conservation (37): 82-
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