Pastiglia

Pastiglia [paˈstiʎʎa], an Italian term meaning "pastework", is low relief decoration, normally modelled in gesso or white lead, applied to build up a surface that may then be gilded or painted, or left plain.

Within paintings, the technique gives areas with a three-dimensional effect, usually those representing inanimate objects, such as foliage decoration on architectural surrounds, halos and details of dress, rather than parts of figures.

In white lead pastiglia on caskets, the subject matter is usually classical, with a special emphasis on stories from Ancient Roman history.

[10] The subjects were typically classical, drawn from both mythology and Ancient Roman history (especially the early period covered by Livy), but biblical ones are also found.

[13] Despite usually having locks, their thin alderwood frame meant that the caskets were probably too fragile to be used for really valuable items like jewellery, and they are thought to have been used for a variety of small objects including cosmetics and collections of seals, coins and the like.

Both panel paintings and gilded frames had a thin flat layer of gesso as part of their preparation, to which the pastiglia decoration was added.

On furniture and frames the gesso seems sometimes to have been carved from a thicker flat surface in a subtractive technique, and sometimes built up in an additive one, for smaller and larger areas respectively.

Another additive technique was to simple pipe the gesso from a bag through a nozzle, like icing a cake, to give long round lines, often used as the tendrils in foliage designs.

In Gothic architectural frames for polyptychs, pastiglia is very commonly used to decorate small flat areas such as spandrels and behind scalloped edges.

[19] In his gold-ground Madonna of the Quail (Verona, attributed), the pastiglia is on the halos and borders of the Virgin's dress at neck and cuff, her crown, and in foliage decoration to the gold "sky", all typical locations in earlier religious paintings.

These are luxury leather bindings which incorporate, normally at the centre of the front cover, small inset plaquettes or roundels with designs in relief, which may be painted in colour.

What may have been Grolier's first such binding has a plaquette with 11 human figures and an architectural setting in a scene about two inches (50 mm) wide, showing Marcus Curtius leaping into the hole, the same subject as on the British Museum casket illustrated at the start of the article.