Plastellina - bevarande av skulpturskisser

Abstract

The aim of this thesis is to investigate the material plasticine from a conservation perspective. The idea came from an existing problem with numerous sculpture models made of plasticine. These are Per Hasselberg's pieces at Gothenburg Museum of Art and Julius Kronberg's collection in his studio at Skansen, Stockholm. A literature survey and a case study which includes an examination of the two collections were carried out. Climate and storage conditions for the objects were different. Some are placed in a museum with controlled relative humidity and temperature, while others are still in their original location in a late 1800’s building. Common damages are cracking, crazing, loss of material and changes in shape and dimensions. Plasticine was developed in the 1890’s as an oil-based modelling clay. Since then, there have been a wide variety of plasticine-like products on the market, with different material compositions. Common for all of them are the three components wax, oil and fillers. No scientific research has been undertaken on the ageing characteristics of plasticine and few articles have been published on preventive and interventive conservation. Some, usually early, brands of plasticine contained sulphur. The emission of volatile sulphur compounds can cause corrosion of nearby metal objects; but despite this, it has been recommended for the mounting of objects. To investigate the sulphur content of Per Hasselberg's model Salve, a SEM-EDX analysis and an Oddy test were performed. The thesis ends with a discussion where recommendations for preventive conservation are given. The most important guideline is to store the objects in a climate where temperature and RH are stable.