Sculpture techniques: wood carving
Regional availability played a large part in determining which wood was chosen for a sculpture, though the properties of individual trees was also a factor. The hardness of a wood depends on the density of its grain. Softwoods from evergreens such as cedar and pine are coarser, less dense and easier to carve, whereas hardwoods from deciduous trees such as oak, boxwood, walnut and limewood, are harder but more durable and allow more elaborate carving and finer details.
In southern Germany, sculptors favoured limewood, but oak was more widely used in northern Germany, the Netherlands, northern France and England. Walnut was used in Burgundy and France, but in Italy, Spain and the Alpine regions pine or poplar were more popular.
Wood is carved in a similar way to stone. The design is drawn on a split tree-trunk, the size of which usually determines the dimensions of the finished sculpture, though extra sections can be pieced in. The form of the sculpture is roughly carved with a broad axe and then shaped with tools such as the narrow axe, flat-headed chisels, gouges and skew-bladed firmers (a kind of chisel with a hooked end used for cutting folds in drapery). After carving, the surface is normally smoothed with sandpaper or other abrasives.
Wood naturally contains moisture when first felled and can re-absorb it later in damp conditions. Cracks usually follow the grain of the wood and are caused when parts dry at different rates. Sculptors therefore try to minimize cracking by removing all superfluous wood, especially the heartwood at the centre of a log. Another cause of damage to wooden sculpture is woodworm. The holes and burrows that woodworm causes are often visible on the surface of older pieces.
Wood sculptors often cooperated with painters as wood sculpture was sometimes painted or decorated with gilding, or embellished with glass or semi-precious stones. At the end of the fifteenth century limewood sculptors in southern Germany produced unpainted wood sculpture. Although these sculptures were not painted, they were coated with transparent glazes, sometimes tinted brown.