Donatello – a master at work

Donatello created a multitude of textures and light effects on his sculptures. He often enhanced surfaces by applying colour, gilding and silvering, to maximise their impact on the viewer. His choice of materials would also have been influenced by the commission, and the purpose for which they were made. The use of expensive gilding – as seen on the Reliquary bust of San Rossore, for example – could carry symbolic meaning and underlined the preciousness of the object. Donatello's fascination with surface treatment and unusual combinations of materials probably derived in part from his early training as a goldsmith. Although none of his goldsmiths' work survives, some of the techniques he learned during his early artistic development can be seen in his later sculptures.

In his early years, between 1404 and 1407, Donatello worked as an assistant in the workshop of Lorenzo Ghiberti – an important sculptor and goldsmith in Florence. Here, Donatello expanded his experience with malleable materials like wax and clay, which were ideal for creating three-dimensional preparatory sketches for sculptures in different materials, and essential for the lost-wax process of bronze casting. Clay could either be pressed into moulds or modelled by hand and with tools to add volume and refine the shape.

Watch contemporary sculptor Charlotte Hubbard recreate Donatello's clay modelling techniques:

Once fired, the clay was transformed into terracotta (literally meaning cooked earth), which could be painted or perhaps glazed. One example, possibly by the young Donatello, is the Seated Virgin and Child, the surface of which is now bare, retaining only fragments from the original colourfully painted surface.

Donatello's workshop also used moulds to create the Forzori Altar, an unfinished model now in the V&A collection, that was presumably fired to preserve it for use in the studio, or to show the patron. The tight-knit workshop environment encouraged a consistent style, which makes it difficult to identify for certain which early terracottas are by Donatello.

Donatello was a talented marble carver, having gained valuable experience working for the Opera del Duomo (the body that governed the works for Florence Cathedral) in the earliest period of his career. One of Donatello's first commissions for the Opera was the marble David, which includes details, like the knotted cloak, which demonstrate the young sculptor's prodigious carving ability.

Donatello carved sculptures both fully in the round, like the David, and in relief (into a panel). His most inventive technique in marble is rilievo schiacciato (literally squashed relief), an extremely shallow relief which conveys a sense of depth by barely grazing the surface with lines that appear to be drawn in the marble. The finest surviving example of this is The Ascension with Christ giving the keys to St Peter, now in the V&A collection. The relief's realistic sense of space is enhanced through the use of linear perspective (a system of creating an illusion of depth on a flat surface) which was a novel introduction to sculpture at the time.

Watch contemporary sculptor Simon Smith recreate Donatello's marble carving techniques:

Donatello also carved in the grey pietra di macigno or pietra serena (a type of sandstone) for the Cavalcanti Annunciation in the basilica of Santa Croce in Florence, Italy, which is embellished with gilding.

Bronze was the most expensive and highly-prized material for sculpture during the Renaissance. Although it was used throughout the Middle Ages, Donatello revived classical imagery in bronze to fit the needs of his Renaissance clientele. He probably first gained experience of bronze production when working as an assistant on the Florence Baptistery doors, under the expert supervision of Lorenzo Ghiberti. From early in his career he created a range of bronze sculptures, both secular and sacred, in relief and in the round, working with a variety of assistants and specialists, including foundrymen who specialised in casting metals. Donatello's most famous bronze is probably the David, the first free-standing male nude (dressed only in hat and boots) since antiquity, which was likely a commission from the powerful Medici family. He probably also created the playful sculpture of Attis-Amorino probably for the Bartolini Salimbeni family, associates of the Medici. Here you can see the texturing on the boy's belt differentiates it from the smoothness of the skin.

A prime example of Donatello's use of gilding on bronze is the relief showing the Miracle of the Mule from the Basilica of St Anthony in Padua, Italy. Here he enhances the intricate architecture in the background with partial gilding and inlay, making it easier to distinguish through the contrast with the darker bronze, and providing a focus for the miracle scene at the centre.

Stucco is a type of plaster made from marble dust mixed with lime and other ingredients. It can be used to create low reliefs and decorative patterns. Like clay, It is far less expensive than marble or bronze and can be used with a mould to replicate an image many times. Donatello created numerous stucco compositions of the Virgin and Child, which were produced by his own workshop and probably others. These devotional images would have then been painted and placed in the home or on street corners, as well as in religious settings.

Donatello experimented with the possibilities of stucco to produce the large tondi (roundels) for the Old Sacristy in San Lorenzo, Italy. These had to be modelled on the spot, working the stucco on nails which helped to keep the moist mixture in place. He chose to leave part of the cream coloured stucco unpainted while colouring the rest with paint and cocciopesto (brick dust), a technique revived from antiquity.

Donatello's use of glass combined his fascination for embellished surfaces with symbolic meaning. The bronze Chellini Madonna is both a finished work and a mould to create glass casts of the same image. The molten glass would have been poured and pressed into the mould in order to create the glass replica. Glass was expensive and was particularly relevant to this depiction of the Virgin Mary who was likened to a transparent vessel. It was thought that the spirit of God could pass through her leaving her immaculate, just as glass can be penetrated by light without being corrupted.

The marble Madonna del Perdono, made for Siena cathedral, features half-moon slivers of a deep blue glass set into the background. These embellishments enhance the background perspective while the glossy texture and dark colour of the glass contrast with the white marble. The choice of blue glass is not accidental, as this colour was associated with Mary as Empress – blue was commonly used to depict her cloak in paintings and sculptures.

Donatello also produced an innovative design for a monumental stained glass window for Florence Cathedral, which challenged the glass-makers in his use of chiaroscuro (light and shadow effects).

Donatello exploited wood for some of his most poignant religious images, evoking the long suffering of the saints Mary Magdalene and John the Baptist who were known for their self-disciplined nature. After being sculpted, the wood was covered with gesso, a type of plaster made from gypsum, which acted as a primer for the paint. The paint was then applied to enhance the life-likeness of the figure. It also allowed the artist to change the look and feel of the wood, masking or exaggerating its texture. In the case of Donatello's Magdalene, the gesso was layered thickly and used to model the hair, with nails underneath to provide structure and support.

The quest for stunning visual effects and novel combinations was at the heart of some of Donatello's most daring sculptural experiments. The relief known as the Madonna dei Cordai is frequently attributed to Donatello because of its style and surprising arrangement of materials. The stucco image of the Virgin and Child lays on a wooden panel, disguised by paint, gilding and decorative punches. To adorn the background, a mosaic made of leather covered in varnished silver and glass has been applied to the wood using wax and glue. The idiosyncratic combination of these materials has unfortunately led to its poor state of conservation, which doesn't allow us to fully appreciate its original striking effect.

Another example is Donatello's Piot Madonna, where the background is decorated with a series of red roundels with wax images of vases and the dove of the Holy Spirit, probably alluding to Mary's role as a pure vessel. Only a few of these survive and most have been replaced with perspex. The terracotta relief was originally gilded, which would have created a stunning contrast between the reflective gilding and the coloured roundels.

Donatello's unusual combination of different materials can also be seen in works such as the Prato Pulpit, made during his partnership with the sculptor and architect Michelozzo in the 1420s – 30s. The work combines a marble relief with a mosaic background. The tesserae (small squares which form the mosaic) are made from a combination of traditional glass paste and small sections of smashed up plates – tiny blue and white patterns are still visible on a few of these. Similarly, in the Cantoria (literally singing gallery, but actually an organ loft) made for Florence Cathedral, small discs of coloured glass paste contrast with the marble, creating a glittering texture.