Sculpture techniques: stone carving
For centuries sculptors have used stone for figurative carvings and ornamental architectural work. Different types of stone were used in different regions, with sculptors generally using geologically local materials available nearby. Marble was used in Italy and exported to northern Europe from about 1550 onwards. It is a particularly brittle stone, which is why supports are often used to connect extremities to the main part of the sculpture. It was usually the intention to remove these once the statue was installed, although this was not always done. Different types of limestone were employed all over Europe, and alabaster was popular in England, northern France, the Netherlands, Germany and Spain.
The heaviness of stone makes stability an important consideration. Many free-standing marble figures in dynamic poses are portrayed with tree trunks or columns attached to the legs in order to provide a stable base. Figures to be displayed in niches were often hollowed out to reduce their weight.
The tools used for stone-carving have remained more or less unchanged since antiquity. A mason’s axe is used to cut out the basic shape of the sculpture, which is then roughed out using picks, points and punches struck by a hammer or mallet. Different sizes of tool are used throughout the carving process, each leaving their mark. Roughing out tools leave deep, uneven grooves whereas flat chisels achieve finer results and are used as a surface finishing tool for sandstone, limestone and marble. A flat chisel struck at an angle of 45 degrees (the ‘mason’s stroke’) leaves a ridged channel, and its edge can be used to define lines. Claw chisels have serrated edges that mean they arc capable of rapid but controlled removal of material. Drills are used to excavate the stone, and can also be used to create decorative effects.
Further smoothing is achieved using rasps or rifflers (metal tools with rough surfaces) or minerals such as sand or emery (stone grit). Polishes can then be applied to sculpture of fine-grained stone after it has been abraded. Marble and alabaster were polished with pumice, producing a smooth, translucent and reflective surface, though the surface could also be left partially unpolished in order to create a variety of textures.