Production and characterization of lead, tin and antimony based yellow
pigments
Claudia Pelosi, Ulderico Santamaria, Giorgia Agresti, Elisabetta Mattei, Alberto De
Santis.
Keywords artificial yellow pigments, colorimetry, XRD, SEM-EDS, micro-Raman
This study deals with the preparation of artificial yellow pigments which have
confusing terminology in the historical references (Seccaroni 2006). By analyzing the
various recipes concerning lead-tin-antimony yellows, it was possible to reconstruct the
original production methods of these pigments, though the experimental conditions are
not clear (temperatures are not indicated, time is often unspecified and materials are not
clearly reported). We produced lead-tin yellow ‘type I’ (Pb2SnO4) and lead-tin yellow
‘type II’ (PbSnO3 or PbSn1-x SixO3) following the indication of the recipes 272 and 273
of the fifteenth century Bolognese Manuscript, lead antimonate yellow (Pb2Sb2O7),
called Naples yellow, according to the treatises written by Piccolpasso, Passeri and
Valerio Mariani from Pesaro, and lead-tin-antimony yellow (Pb2SnSbO6,5) from the
Darduin, Valerio Mariani da Pesaro and other authors. More recent work, dealing with
the production and analysis of artificial yellow pigments, were taken into account
(Cascales et al. 1986; Clark et al.1995; Kuhn 1993; Moretti et al. 1984).
The study of lead, tin and antimony based yellow pigments, produced in a laboratory
using ancient procedures, is also useful for investigations on similar materials used in
works of art (Pelosi et al. 2007). Indeed, it is very probable that the artists chose their
painting materials by selecting not only the colour of the pigments but also the
production method. Therefore, it is important to state a correlation between chemical
compositions, ancient production methods, and the final colour of the produced yellow
pigments.
The production of lead-tin-antimony based yellow pigments was obtained by pure
chemical oxides (PbO, Pb3O4, SnO2, Sb2O3 and SiO2), supplied by Across. Sodium
chloride, used in the production of lead antimoniate according to the recipe of Valerio
Mariani from Pesaro, was supplied by ICN. The oxides were mixed in agate mortars
and then introduced into the furnace at room temperature. They were warmed up to the
required temperature. The temperature was maintained constant for 5 hours. Only for
the production of lead-tin yellow type I a time of 3 h was also tested. Then the samples
were allowed to cool slowly inside the furnace. In order to evaluate the influence of
cooling condition, lead-tin-antimony yellow was also cooled in cold water at 10 °C. The
temperature was different according to the typology of pigment to be produced (670,
800 and 900 °C for lead-tin yellow type I and type II; 900, 950 and 1050 °C for lead
antimonate; 925 °C for lead-tin-antimony yellow). For the production of lead-tin
yellows porcelain crucibles were used; for lead antimonate and lead-tin-antimony
yellow porcelain crucibles and terracotta tiles covered by filter paper were used. The
obtained products were characterized by SEM-EDX, XRD and micro-Raman analyses.
Colour measurements were performed on the ground samples with an X-Rite
spectrophotometer according to CIE 1931 and CIE 1976 specifications, employing light
sources C and D65 and a 10° observer. Colour parameters were mathematically treated
to obtain the dominant wavelength (λd) and the colour purity (P%).
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Lead-tin yellow type I was produced at a temperature of 800 °C for 5 hours. At a lower
temperature the compound Pb2SnO4 was not completely formed. The correct
stoichiometric ratio was Pb:Sn = 2:1; the volume ratio was incorrect. Using Pb3O4 or
PbO does not change the final product. Lead-tin yellow type II was produced at a
temperature of 800 °C or higher using the compound Pb2SnO4 and SiO2 (10% w/w). At
lower temperatures a mixture of Pb2SnO4 and PbSnO3 was formed.
Lead antimonate, or Naples yellow, was obtained with two different recipes: the first
one using only the pure chemical oxides (Pb3O4 and Sb2O3); the second adding NaCl to
PbO and Sb2O3, according to Valerio Mariani from Pesaro. In both cases a mixture of
compound was obtained. The best pigment was produced at 900 °C for 5 hours with a
stoichiometric ratio Pb:Sb=1:1 over terracotta tile. In this sample the compound
Pb2Sb2O7 was identified by XRD, SEM-EDX and micro-Raman analyses. The addition
of NaCl probably led to the production of oxychlorides which were not well
characterized.
Finally, lead-tin-antimony yellow was produced at 925 °C for 5 hours. The obtained
compound corresponds to the formula Pb2SnSbO6,5 (JCPDS 39-0928). Experimental
tests showed that a mixture of compound was often produced and that temperature
played an important role in the composition and colour (hue and purity) of the produced
pigments. The stoichiometric ratio of the metallic elements in the chemical oxides was
also an important parameter. In fact the use of a volume ratio led to the production of
the expected pigments, but some reagents remained in the final product. For the
production of lead antimonate further experimental tests must be carried out in order to
understand the role of temperature, type of crucible and ingredients. In this preliminary
phase of the research we chose to make a simplification of the recipes, in particular to
eliminate some ingredients whose role was not completely clear. Further experimental
tests will be tried out to obtain a better understanding of the role of these ingredients
(zinc oxide, lees of wine i.e. potassium hydrogen tartrate and NaCl) indicated in the
recipes.
References
Cascales, C., Alonso, J.A. andRasines, I. 1986. ‘The new pyrochlores Pb2(MSb)O6,5
(M=Ti, Zr, Sn, Hf)’, Journal of Materials Science Letters, 5:675-677.
Clark, R.J.H., Cridland, L., Kariuki, B.M, Harris and K.D.M., Withnall, R. 1995.
‘Synthesis, structural characterisation and raman spectroscopy of the inorganic
pigments lead tin yellow types I and II and lead antimonate yellow: their identification
on medieval paintings and manuscripts’, Journal of the Chemical Society-Dalton
Transactions, 16:2577-2582.
Kuhn, H. 1993. ‘Lead-Tin yellow’. In A. Roy (ed.), Artists’s Pigments, vol. 2, (ed.),
Washington: National Gallery of Art, 83-112.
Moretti, C. and Hrelich, S. 1984. ‘Opacizzazione e colorazione del vetro mediante le
anime’, Rivista della Stazione Sperimentale del Vetro, 1:17-22 e 2:83-87.
Pelosi, C., Santamaria, U., Morresi, F., Agresti, G., De Santis, A. and Mattei, E. 2007. ‘I
gialli di piombo, stagno, antimonio: le opere di Poussin e Saraceni’, in Claudio
D’Amico (Ed.), Atti del IV Congresso Nazionale di Archeometria, Padova: Pàtron
Editore, 81-94.
Seccaroni, C. 2006. Giallorino. Storia dei pigmenti gialli di natura sintetica. Roma: De
Luca Editore.
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Authors’ addresses
Claudia Pelosi, Facoltà di Conservazione dei Beni Culturali, Largo dell’Università,
01100 Viterbo, Italy. (labdiac@unitus.it)
Ulderico Santamaria, Facoltà di Conservazione dei Beni Culturali, Largo
dell’Università, 01100 Viterbo, Italy, and Laboratorio Scientifico dei Musei Vaticani.
Giorgia Agresti, Facoltà di Conservazione dei Beni Culturali, Largo dell’Università,
01100 Viterbo, Italy.
Elisabetta Mattei, Facoltà di Agraria, Via S. Camillo De Lellis , 01100 Viterbo, Italy.
Alberto De Santis, Facoltà di Agraria, Via S. Camillo De Lellis , 01100 Viterbo, Italy.
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