Paper Conservation: Decisions & Compromises

Fig. 3: A woman under a blossoming tree, Wilanow Palace Museum,
photo by T. Rizov-Ciechanski, a fragment and a close-up of the fragment
of a glittering background
of calcium carbonate. Also, a certain quantity
of titanium, magnesium as well as traces of sulphur
and chlorine were detected. The presence
of titanium combined with partial resistance to
acid as well as of very small particles viewed in
transmitted light might indicate that there was a
titanium dioxide white pigment which may have
come from overpaints. The presence of magnesium
can be connected with calcium carbonate
(magnesium content of calcite). Large calcium
carbonate particles make it possible to conclude
that a naturally derived calcite was used (for example,
coming from a limestone or shells). The
presence of anorgenic limestone was excluded
because it has a very different microscopic morphology.
Mineral forms of carbonate were widely used
throughout the world. The Chinese tradition of
calcining and slaking crustacean shells in order
to obtain shell white dates back to antiquity. Titanium
white is a synthetic pigment that has been
produced on a larger scale since 1920. The fact
that it was used means that there were conservation
interventions that took place in the European
area at a later time.
The second object (Fig. 2) depicting “A woman
under a blossoming tree” was an element of a
wall decoration in the Chinese Cabinet, a part
of Count Potocki’s Chinese Suite which was furnished
first. Three other similar objects were also
used as the cabinet’s decoration. It is not known
when they were brought to Wilanow or whether
they were reused to decorate the cabinet and if
they had not been used as a decorative element
in another room before.
It is a representation which is typical of
Chinese art exported to Europe. Thematically
and technically similar woodcuts are located
in the Schloss Favorite palace in Rastatt. The
large object (163 x 90 cm) was made by using
the woodcut technique, with painted parts (the
objects from Rastatt were identified as woodcuts
by F. Wappenschmidt), or it may have been only
painted. It dates back to the second half of the
eighteenth century, to the Qianlong period.
A sheet of paper was used as a surface; it was
obtained by gluing the overlapping edges of five
sheets of paper made from Broussonetia Papyrifera
fibres and then it was lined with three sheets of
paper, which was also made from Broussonetia
Papyrifera.
The paper was dyed yellow and covered with
a glittery substance (Fig. 3), the composition of
which is still being subjected to additional studies,
and dusted with metallic powder. Colours
were applied onto a surface prepared in this way.
Initially it was suspected that the surface was
dusted with powdered metallic tin and sprinkled
with ink or paint as there were clearly different
colours. Analyses performed using the XRF method
did not reveal any other metals (gold, silver),
whereas tin was found in all studied locations. In
order to confirm the results, studies were carried
out by using the SEM-EDS mapping technique.
In the tested sample of paper, all dots, also the
black and brown ones, contained tin, but no pigments
or organic compounds were identified.
The size of the dots ranged between 0.02 and 0.4
mm. The sample was analysed using Raman spectroscopy.
Tin oxide was identified in small, dark
brown dots.
The layers of colour were applied using paints
with an emulsion binder containing glutin
glue and vegetable oil (FTIR analysis showed
that there were lipid and protein substances).
Colours, which were slightly transparent, were
applied in very thin layers (the layers were 0.007–
0.049 mm thick). In the paints, for example calcium
carbonate, copper green, white lead, smalt,
orpiment, organic red, and minium were identified.
The performed studies and analyses were aimed
at establishing the work’s substance. Complementary
studies of the objects’ content and
ICOM-CC Graphic Documents Working Group Interim Meeting | Vienna 17 – 19 April 2013
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