Historical Painting Techniques, Materials, and Studio Practice

Abstract
The problems of interpretation of
written sources on painting technique
are well known. Through loss
of the technical tradition, within
which details of information were
well understood at the time of writing,
technical information is obscured
fo r later generations. In
courses on historical techniques of
painting at the School of Conservation
in Copenhagen, attempts at reconstructing
the kind of gesso
ground used in early Italian painting
have prompted investigation into the
actual meaning of the "giesso uolteriano"
mentioned by Cennino Cennini
in his treatise. This paper examines
the problem from three angles:
(1) the possible meanings of Cennini's
text on this point; (2) the preparation
of gesso grounds from the
possible fo rms of gesso resulting
from the first point (dihydrate, hemihydrate,
anhydrite); and (3) technical
evaluation of the reconstructions and
comparison with the results of scientific
examination of grounds in early
Italian painting.
Questions about Medieval Gesso Grounds
Beate Federspiel
Konservators Skolen
Danske Kunst Akademie
Esplanaden 34
1263 Kopenhagen-K
Denmark
Introduction
The problems in interpreting written sources on painting techniques are well
known. Besides the paintings themselves, the written sources are the only
testimony of materials and techniques used in former times. Advanced methods
of scientific analysis employed in the examination of paintings do not
always answer questions about materials and techniques. And the written
sources do not always provide easy access to painting techniques. Time has
obscured the comprehension of the texts. The pure linguistic translation of a
written source is often far from sufficient, but may be greatly aided by reconstructing
the technical details described and comparing the results of the
scientific analyses.
Understanding Cennini's text
During the courses in historical techniques of painting at the School of Conservation
in Copenhagen, it was increasingly dissatisfying for the author and
others to reconstruct the gesso grounds as described by Cennino Cennini,
and it was eventually necessary to scrutinize his text concerning grounds.
Merely reading Cennini's instructions in the English translation by D. V
Thompson in 1933 was not sufficient; it was obvious that things were not as
easy as they may have seemed (1). Not that Cennini is imprecise in his instructions
on this point; he is more thorough in his instructions on ground
than in his description of paint application. But how can certain important
passages be interpreted 600 years later?
The original manuscript by Cennini being lost, the question of which surviving
copy to use as a source remains, of course, a central one. That aspect
will not be addressed in this article; the source used here is Lindberg's Swedish
version of Cennini's Codex Laurentianus. Lindberg's translation shows semantic
details, absent in previous translations, that are important for the understanding
of decisive technical details (2).
In Chapter CXV of his treatise, for example, Cennini describes the preparation
of the ground for painting on panel. Painting in the Middle Ages
included gilding. Gilding was the main reason for the great efforts invested
in creating a perfect ground. Gypsum was the material used in the preparations
of grounds for painting and gilding throughout the whole Mediterranean
area as far back as the first millennium B.C.E. (3). The first written
evidence of a ground for painting made of gypsum appears in the ninthcentury
Lucca manuscript, which mentions a ground consisting of gypsum
and glue for gilding on wood (4) . Cennini clearly distinguishes between gesso
grosso and gesso sotille; that is, a double-structured ground consisting of several
layers of a coarse ground on top of which are applied several layers of a finer
ground. In both structures, the medium is animal glue (5). Such grounds, with
local variations, were found in fourteenth- and fifteenth-century paintings
from Florence and Siena (6) .
Lindberg's translation, here translated from Swedish into English by the author
(7), differs in several crucial passages from the 1933 English translation by D.
V Thompson. The passage concerned is the following: The Italian text says,
"poi abbi giesso grosso cioe uolteriano che e purghato ede tamigiato amodo
di farina, ..." which Thompson translates as, "then take some gesso grosso,
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Historical Painting Techniques, Materials, and Studio Practice