http://www.kunsthaus.ch/en/the-collection/conservation/examples-from-the-world-of-art-conservation/progress-report-october-2010-to-april-2011/?redirect_url=title%3Dmet

Kunsthaus Zürich

Progress report: October 2010 to April 2011

Definition of the main areas of research and systematization of work processes

Initial detailed examination of the plaster sculptures showed that the success of the research work would depend not only on clearly formulated questions, but also on a solid structuring of the information that was obtained. The focus for the first three months was therefore on systematizing workflows and defining standards for photographic and written documentation.

The main areas of research have been defined more clearly, such that the plaster sculptures are examined according to their origin, production techniques and function. This means looking at the original models – the individual plaster works – and contemplating the methods employed during their production and the designated purpose of each object – i.e. whether or not it was used as a model to make further castings.

The resulting information is then presented as far as possible in a broader context. Thus, for example, fragments of plaster lodged in the depressions of a sculpture indicate that it was produced using a negative plaster mould (see fig. 1). This detail is important because it proves that the sculpture is a direct cast from the original clay model. Or one finds traces of gelatine left over from subsequent castings (see fig 2). Cuts or scratches on the surface are not necessarily indicators of damage, but can provide important information on how subsequent castings were carried out (see fig. 3).

Comparative protocols in the form of posters represent a useful resource in day-to-day working practice. They enable the most important information about an object to be readily compared with that of other objects (link: sample poster).

The photographic recording of UV fluorescence was fully integrated into the process. This method is not a qualitative technique. Information gained in this way is not absolute but has to be corroborated constantly by means of further investigations. However, it helps to better differentiate certain surface phenomena, such as deposits (e.g. release agents used in de-moulding, and agents used for hardening the plaster), gelatine, and fragments of plaster lodged in the surface (see figs. 4 and 5). UV fluorescence testing enabled us to establish that sometimes more than one treatment had been carried out, or that due to a conspicuous chromaticity, a presumed use of materials would have to be looked into. For example, shellac, a release agent that is applied before casting, fluoresces bright orange, whereas protein glue shows up as a rather cool bluish green. In addition to acquiring a collection of findings, a series of experiments: ‘Moulding methods: from clay to plaster. From plaster to plaster’ – was conducted at the end of 2010 that aimed at simulating the sort of casting-specific surface phenomena found on Alberto Giacometti’s plaster sculptures. A clay model was deliberately provided with tool marks and fingerprints à la Alberto Giacometti (see fig. 6). A two-section plaster mould was then made from this model, and the clay model removed. After the negative form had been repeatedly coated with shellac and Vaseline it could be filled once again with plaster. The resulting surface damage, which is virtually unavoidable when a plaster object is removed from its plaster mould (see fig. 7), could then be compared directly with damage on the plaster original.

Once released from the mould, the positive plaster cast was coated again, as described above, and a two-section gelatine mould was made (see fig. 8). It became evident that every single stage of this procedure left its trace on the surface of the plaster objects. When these traces are clearly identifiable, it is possible to make relatively unambiguous statements about the origin, production techniques and the later use of a Giacometti plaster sculpture. However, a number of questions remain open.

Fig. 1: Detail of a fragment of plaster lodged in the surface. © 2011 Kunsthaus Zurich
Fig. 1: Detail of a fragment of plaster lodged in the surface.
© 2011 Kunsthaus Zurich
Fig. 2: Detail of a piece of gelatine stuck to the surface. ©2011 Kunsthaus Zurich
Fig. 2: Detail of a piece of gelatine stuck to the surface.
©2011 Kunsthaus Zurich
Fig. 3: Cuts caused during removal of gelatine mould © 2011 Kunsthaus Zurich
Fig. 3: Cuts caused during removal of gelatine mould
© 2011 Kunsthaus Zurich
Fig. 4: Comparison of chromaticity of three plaster works. GS 334, GS 322, GS 309 © Alberto Giacometti Estate / ProLitteris, Zürich
Fig. 4: Comparison of chromaticity of three plaster works. GS 334, GS 322, GS 309
© Alberto Giacometti Estate / ProLitteris, Zürich
Fig. 5: Comparison of UV fluorescence from three plaster works. GS 334, GS 322, GS 309 © Alberto Giacometti Estate / ProLitteris, Zürich
Fig. 5: Comparison of UV fluorescence from three plaster works. GS 334, GS 322, GS 309
© Alberto Giacometti Estate / ProLitteris, Zürich