Hoofdpagina van Kristallografie. Thesis by Dr. J. Dik
SUMMARY
This thesis describes a research project in the field of technical
art history. Subjects of this study are the production history of Naples
Yellow and the discolouration of smalt. Naples Yellow, or lead antimonate
yellow, is the most important synthetic yellow pigment in the history of
the visual arts. The usage of lead antimonate covers a period of more than
3500 years, the first application of the pigment dating back to the 18th
Egyptian dynasty (ca. 1500 BC). The production history of the pigment, notably
over the past few centuries, is rather diverse and not well understood. This
research project focussed on the European history of the pigment from the
16th to 19th century. The aim of this study was to describe different manufacturing
methods and, subsequently, different forms of lead antimonate used at different
periods over time. Secondly, the discolouration phenomenon of the blue painting
pigment smalt was studied. Based on a number of analytical techniques a digital
reconstruction showing the approximate original appearance of a smalt-discoloured
painting.
Unraveling the history of the manufacture of Naples Yellow
requirs a close comparative research studying textual sources as well as scientific
analysis of authentic pigment material. After interpretation of historical
production literature, reconstructions of the pigments are made according
to the descriptions in these sources. Subsequently, these reconstructions
are studied using various analytical techniques. Both paths of research,
scholarly interpretation of sources and scientific analysis of art objects,
as well as some peculiarities of such interdisciplinary research are discussed
in chapter 1.
During the Middle Ages the application of lead antimonate
yellow seems to have been limited to the Eastern Mediterranean. In the early
16th century the use of the pigment is then suddenly taken over by Italian
ceramic artists. The circumstances under which lead antimonate suddenly
popped up in Italian Renaissance are investigated in chapter 2. Two contemporary
Italian manuscripts are discussed in which the synthesis of lead antimonate
yellow is described under the nomenclature of Potters’ Yellow. Reconstructions
according to these pigment recipes show that at least three, possibly four
different types of lead antimonate can be produced. Some of these types,
notably lead tin antimonate, have been found in earlier studies. No evidence
was found for a locally limited use of this type of Naples Yellow, as has
been suggested in earlier studies. These findings should therefore be of
interest to authenticity studies. Documentary and analytical evidence indicates
that the knowledge on lead antimonate yellows originates from Middle East
ceramical and glass industries. It is argued that the know-how on the production
of lead antimonate yellows has been transferred through the migration of
glass artists from the Eastern Mediterranean to Venice during the 15th century.
Chapter 3 deals with the introduction of lead antimonate yellow
in Northern European painter studio’s after 1700. North European painters,
however, hardly applied Naples Yellow before 1700. Instead, the traditional
pigment lead-tin yellow remained highly popular until about 1730, when it
was replaced gradually by Naples Yellow. When the pigment was first imported
from Italy, the origin of Naples Yellow remained a mystery to North European
artists and craftsmen. Only during the second half of the 18th century Germans,
Frenchmen and Dutchmen seemed to have learned to produce lead antimonate
themselves. This development is discussed from technical, economical and
art historical points of view. In addition, a contemporary Northern European
manual is examined and pigments are reconstructed according to the descriptions
given by the manual. The results show interesting characteristics of 18th
century lead antimonates that clearly differ from earlier Italian types,
which could be helpful in art historical authenticity questions.
Various original samples of 19th century lead antimonate yellow
have been preserved in several historical pigment collections, such as the
Hafkenscheidt collection at the Teylers Museum (Haarlem, Holland) and the
Turner pigment collection at the Tate Gallery (London, UK). In chapter 4
pigment samples are subjected to extensive analysis, including synchrotron-
as well as laboratory-based X-ray powder diffraction and single crystal electron
diffraction. Again, chemical characteristics of these samples are discussed
in the context of 19th century textual sources on lead antimonate yellow.
In addition, a new phase of lead antimonate (Pb2SbOx
4.5≤x≤6.5) has been discovered.
While the earlier chapters deal with chronological characteristics
of lead antimonate production, chapter 5 is aimed at locating the geographical
origin of the pigment. Lead isotope analysis (LIA) is used to determine
the exact isotopic ratio of naturally occurring lead in lead-bearing material.
Given the exact knowledge of isotopic characteristics of ores, it is in
principal possible to deduce the ore source of the lead. LIA was performed
on a few 18th and early 19th century samples of lead antimonate yellow.
Samples were taken from historical pigment collections as well as a painting
of known date and origin. The results show that the method can be applied
successfully to the study of paint samples.
Chapter 6 discusses the digital colour reconstruction of a
17th century Dutch painting containing discoloured smalt. Smalt is one of
the most common 17th century blue painting pigments. Smalt consists of cobalt-coloured
potassium-enriched glass, that is ground to a fine, intensely blue powder.
Being at the time a relatively cheap pigment, smalt was used as a substitute
for other, more costly pigments roughly between the 15th and 17th centuries.
As main disadvantage, however, smalt has shown to discolour over the years.
The paintings of the Dutch painter Hendrick Ter Brugghen show severe signs
of smalt discolouration. A dramatic example of such degradation can be seen
in his painting St Luke. Employing a variety of analytical techniques, this
chapter presents the digital reconstruction of the approximate original
appearance of a painting suffering from severe smalt discolouration. The
chapter also discusses the pictorial and art historical implications of
paint discolouration.
Overzicht proefschriften kristallografie Amsterdam.
Hoofdpagina van Kristallografie.