Process
Henry Moore carving plaster maquette for Three Way piece No.2: Archer 1964-65. Photograph: Errol Jackson
Henry Moore carving plaster maquette for Three Way Piece No.2: Archer 1964-65. Photograph: Errol Jackson.
The maquette
 Moore would begin working with a soft material such as clay, plaster, or plasticine. He would make a small model, or maquette, that he could turn in his hands, viewing it from every angle. He commented, 'When I take one in my hand . . . I am seeing and feeling it as life-size.'

The works you are looking at on these pages are maquettes and are small versions of large works in the exhibition Henry Moore: journey through form

The working model
Once Moore decided that a particular maquette was suitable for enlargement, he would produce a larger working model. For enlarging in plaster, a wooden or metal armature or frame would be built up to support the plaster sculpture. When the basic form was complete, the surface finish was achieved using tools such as spatulas, knives, trowels, cheese or nutmeg graters, and even dentists' tools.

Henry Moore working on polystyrene for Large Spindle Piece 1966/1974, Perry Green 1977.
Henry Moore working on polystyrene for Large Spindle Piece 1966/1974, Perry Green 1977. Photograph: Errol Jackson.

Having first used polystyrene in the early 1960s for a stage set design, Moore realised that this easily shaped and portable material could simplify the enlargement process by eliminating the need for an armature. However, he still had to make a plaster cast from the polystyrene enlargement in order to add the surface markings and modelling.

The 'lost-wax' process
The plaster model would then be sent to a foundry for casting using the 'lost-wax' process. During this complex procedure, a rubber mould is taken from the plaster so that a wax replica can be made. The wax is enclosed in further moulds, then melted out and replaced by molten bronze, leaving a hollow bronze cast that is finished and patinated to give the desired surface texture and colour. The mould used to cast one of the small Three Interior Forms about 1975 (CN 1787.1-3) can be seen here, as well as the moulds used to cast the maquette for Helmet Head No.6 1975 (LH 650). Further enlargement used a cast of the working model as a reference with a grid system to scale it up.