School of Hard Knocks

Peter Campbell

  • The Materials of Sculpture by Nicholas Penny
    Yale, 318 pp, £35.00, November 1993, ISBN 0 300 05556 0

There are two forces at work in sculpture. One pushes it towards the waxwork, where materials suggest something quite contrary to their native qualities – marble flesh, wooden flowers, metal drapery and so on. The other takes it towards material for material’s sake, towards the pebble which lives by its pebble-ish nature alone. Nicholas Penny’s book shows how these forces are reconciled.

Materials bring meanings with them. Not even the most resonantly-named dyes and pigments (‘vermilion’, ‘ultramarine’, ‘indigo’) carry as much baggage as ‘alabaster’, ‘marble’, ‘onyx’ or ‘bronze’. While a history of the materials of painting could be compressed into a simple chronology, the materials used in sculpture demand their own chapters. Which is what Penny gives them – one each for hard stones, marble, coloured marble, wood, ivory, modelled clay and wax, cast bronze, embossed and chased metal, and so on. Of each material the same kind of questions are asked: in what sizes, colours and quantities was it available? How was it cut, cast, polished or patinated? How strong, heavy, malleable, is it? The book, like a natural history, is most interesting when it is most particular; when, for example, it offers a commentary on an individual piece.

The Blessed Stanislas Kostka was commissioned in 1702 by the Jesuits in Rome from the French sculptor Pierre Legros to promote the veneration of a pious Polish novice. He is represented lying on his deathbed wearing a robe of black Belgian marble. His face, hands and pillows are of white Carrara marble, the mattress is yellow marble and the cover below banded calcite. Although it is displayed in the room where the boy died the effect is not, Penny points out, illusionistic – as a waxwork in real clothes would be. Its polished stone is ‘at once more seductive and precious, and more durable, as befits a figure that is to be cherished and venerated’. In the post-Roman centuries some kinds of stone became precious in the way protected hardwoods like Australian Black Bean are precious today. The only sources were exhausted or lost, and the calcite base of the bed that Kostka lies on came from excavations of a Roman villa. It was not just the scale of ancient monuments which seemed magical, but the very stuff of which they were made. For centuries Roman ruins were the only source of porphyry, as Penny explains:

Even after the dissolution of the Empire of the West, porphyry enjoyed a special prestige, for the dream of reviving Roman imperial authority was never forgotten. However the quarries had been closed in the early fifth century, and the only way of obtaining the material was to reuse what remained of ancient Roman architecture and sculpture, as well as the blocks of unworked stone that remained in Rome. The porphyry disks set into medieval church floors in Rome were sawn from ancient columns found among the ruins. Those ornamenting the façades of Venetian palaces were cut from columns looted from Constantinople (some of which had, long before, been removed from Rome).

The Kostka mixes materials in a way which was more common than a conception of sculpture centred on the cast bronze and carved stone pieces in galleries dominated by 18th and 19th-century sculpture would suggest. There was Greek ‘acrolithic’ sculpture: pieces with marble heads and hands and limestone drapery as well as mixtures of bronze and stone and wood and stone. Sculptures were even dressed in real fabric – a clay sketch of another figure of Kostka by the 18th-century sculptor Antonio Calegari is draped in cotton dipped in clay slip. Is this a cheat? Rodin once had to defend himself from the accusation of using casts from life – but applying casts of jewellery, for example, to modelled figures was a regular practice.

Some details of style are in fact forced by the physical qualities of materials. Tensile strength, for example. A reclining figure like the Kostka does not demand much. The projecting limbs of standing figures do – hence the adventitious tree stumps which appear as supports at the feet of Roman marble copies of Greek bronze figures. Elegant solutions to the problem of support are possible. Thus Penny on Bernini’s Apollo and Daphne: ‘It would be impossible for Apollo to remain upright without the support provided by Daphne, to whom he is attached where he touches her, where her hair streams onto his shoulder and where some laurel touches the cloud of drapery that floats across his waist – at each of these points there is a firm bridge of marble, but the form discourages analysis of function.’

Strength puts a limit on projection, hardness puts one on cutting and shaping. If a material is so hard that it must be ground down with abrasives, undercutting is avoided and features tend to be rounded and polished – this is the case in Egyptian hard stone figures. The economy of modelling in some jade pieces can also be read as an expression of the hardness of the material. But hardness is relative, and changes in technology encouraged sculptors to meet the challenge and cut jade into complex shapes. By the late 19th century there were tools available which allowed hard stone like granite to be cut as easily as sandstone and limestone.

Size itself is a quality. While some materials are available in more or less any size and have no grain or planes of cleavage – steel, plastics and concrete are obvious instances – organic materials and many kinds of stone have characteristic sizes and shapes which determine the proportions of sculpture made from them. Jade was and is precious because of its colour, hardness and texture. But it is seldom found in large pieces – the ancient source was river beds. A large piece of jade in a jade-using culture will be recognised as a prodigy – think of the large slab of black jade which served as Timur’s cenotaph. The shape of ivory sculpture carries the memory of the tooth or tusk it was carved from both in the long curve of tall pieces like the medieval carvings of the Virgin and Child and in the shallow curve of low-relief panels cut from the tusk’s broad hollow end. Sedimentary rocks which split on the bedding plane force the sculptor to find his shapes in a slab not a block. Hard, fine-grained woods like box and ebony come in smallish pieces – more batons than logs.

One way of meeting the limitation nature puts on the size and shape of workpieces is to shape the idea to the material. But it’s also possible to stick a bit more on. The gold collar worn by a 16th-century rock-crystal bird is there to keep its head on. If a single trunk did not serve, German limewood sculptors added a bit here and another bit there; even in the 18th and 19th centuries, when the integrity of the marble block (which, unlike limewood, was not destined to be painted) was more respected, it was allowable for Canova simply to add on Cupid’s wings.

Because materials have a character and value of their own they sometimes compete with the artist and subvert his or her intentions. Speaking of a piece in gypsum alabaster, Penny writes: ‘The stone is white but with a few brown streaks in it and a network of translucent veinings, giving it an organic appearance, even more so than that of ivory, and this, together with its softness, makes it an almost alarming material in which to see naked flesh represented.’ The materials of painting never assert their individuality in this way. The life of a piece of sculpture may of course be endangered by the material it is made of: bronzes were melted down to make canons; Inca gold sculpture was pretty often turned into ingots.

The process of making can sometimes be understood by just looking at a surface. Penny shows a detail from Michelangelo’s unfinished Virgin and Child of 1521-3 on which the marks of a claw chisel can be seen – they follow and cross planes like the hatching of a drawing or engraving. It is easy to think that pleasure in the look of such unfinished surfaces is a modern one and therefore salutary to be told that they were appreciated by Michelangelo’s contemporaries. But they were not left to be admired – except in details like the rock the David stands on, where rusticity was appropriate. Rodin’s way of leaving figures half in and half out of the block, and letting the lines show where piece-moulds joined on bronzes, was evidence of his tenderness for the unfinished state – but these things can easily become mannerisms.

On the other hand, more sculpture has, in its making, involved the destruction of admirable intermediate states. One thinks of the Riemenschneider’s woodcarvings, softened by their coat of plaster, and of bronzes which, although more durable, are not necessarily an improvement on the clay or plaster models from which they were cast. Early stages in the making of a painting may have a similar validity (the invention of photography has allowed them to be judged), and early states of engravings have always been taken seriously, but in sculpture the authority of intermediate stages is particularly strong. They are part of a drama. The building up of a model in clay or plaster, or the revelation of the work ‘hidden’ in a block of stone, has something of the character of an alchemical transformation.

Although Michelangelo’s hatchings are direct evidence of the cuts he made, the marks of his claw chisel, like those of an engraver’s burin, are the result of whole arm movements. It is their virtue, and their limitation, to have a mechanical precision and vigour. Only modelling in a soft medium like wax or clay allows all the variations of weight which one associates with a brush or piece of chalk, and a more personal, calligraphic kind of mark. The reliefs of Clodion have elements defined by incisions which are literally drawn, and the ability of wax to preserve the gestures of the modeller’s fingers make some pieces – like the horse with stable hand and jockey by Pierre-Jules Mène reproduced in the book – so fluent that the difference between a sketch drawn on paper and a modelled one seems less than that between a modelled sketch and finished sculpture. It was with such wax figures that Degas, Daumier and, before them, Gainsborough and Poussin explored the no-man’s-land between two and three-dimensional representation.

Casts have their disciplines too. Before the invention of flexible moulds, moulds of undercut or branched objects (like bodies) had to be made in several pieces and reunited for casting. Or several casts had to be joined to make complete sculptures. The technical skill involved in the making of the two Greek bronzes of warriors found in the Adriatic Sea near Riace in 1972 is astounding. A little more than life-size and dated around the fifth or fourth century BC, they have enabled us to make firm conjectures about methods. These figures began as models in clay. Moulds were taken and lined with wax. The wax casts were joined to make a hollow version of the original clay figure, but with additions, for ‘it was at this stage that the model may have been given hair and beard or even ears and genitals which would have been troublesome to mould in the original model.’ The wax figure was filled with a poured core and a supporting armature, then the figure was invested – or rather most of it was. Some parts, the ‘head, arms, and front of the feet ... and some of the smaller parts – the middle toes, the scrotum, penis, much of the beard and many of the hanging locks of hair’ – were cast separately. The invested casts were heated to melt out the wax and harden the core. The bronze was then poured into the thin space between core and mould. Consider some of the problems: the space out of which the wax had run and into which the bronze would go had to be vented to allow gas to escape; if the core and mould were not to fall together when the wax ran out they had to be joined by pins which acted as spacers. When the delicate business of pouring was over and the casts had been broken out of their moulds, separate pieces had to be joined – in this case molten bronze was run into grooves cut into the thickness of the metal. The lips had been pre-cast in copper and inserted into the wax cast, and were thus married to the bronze of the head. The nipples, also cast in copper, were added separately and fixed by hammering the surrounding bronze. Eyes (ivory or marble) with copper eyelashes were inserted, as were silver teeth. ‘ “Realism” ’ Penny writes, ‘is an inadequate word for the sculptor’s aim, when we consider the calculations behind the physical proportions of these beings. But “ideal” seems an anodyne term for creations of so alarming a particularity, their impressive, but menacing, power as warriors – that is killers – enhanced by the gleam of their teeth and eyes.’

There is one material made use of by every piece of sculpture with the exception of the pebble you turn over in the dark. That is light. The illustrations here are all admirably reproduced, most of them from photographs which are instances of craftsmanship in their own right; but any photograph is in some degree a commentary on what it represents. Of the effect of Bernini’s monument to Pope Alexander VII, Penny says: ‘In the dim light of the basilica it is the glowing white marble and the shimmering diasporo of which we are most aware; but the electric light with which the tomb has been flooded for the photograph illustrated here gives prominence to all the coloured marbles.’ Elsewhere he writes of Japanese coloured wooden sculpture that ‘this type of surface decoration, as with European painted and gilded sculpture, was designed for relatively dim interiors with artificial light, which was not intended – as is correct or good lighting today – to supply uniform, informative illumination, but rather to add animation and mystery.’ Much of the sculpture shown here is easy to see: Penny has chosen to write about pieces he knows well and the Ashmolean, the V&A and the British Museum provide a good proportion of his plates. Face to face, in ‘good’ or perhaps less than good light, they haven’t got the glitter which photography allows them, nor the drama their makers sometimes intended. But as sculpture and its materials can only be truly known face to face (or, sometimes, if you are lucky, stone or bronze to skin) the encouragement this book gives to inquisitiveness is admirable.