Heraldry as art: An account of its development and practice, chiefly in England

by G. W. Eve

Among the materials suitable for interior decoration gesso is an excellent means of obtaining relief in work that is to be painted, and it is more readily handled than modelled plaster, from the ease with which it can be kept moist. In early work the smaller details of monuments were frequently modelled in this material, as were the arms on some of the stone shields in Westminster Abbey; and on the decorative panelling, on which jewels and enamels were also modelled and painted.

Gesso is simply the Italian name for Plaster of Paris, burnt gypsum, but is technically understood to mean a preparation of plaster or other material which depends for its hardening on the solidifying of some cohesive medium, usually a form of glue, and not on chemical action in the material.

Methods of making gesso are described by Cennino Cennini in the MS., written in 1437, in which he describes minutely the technical practices of his time. First the plaster is to be “well washed and kept moist in a tub for at least a month” and is to be stirred up well every day until “it almost rots and is completely slaked and it will become soft as silk.” It was then made into cakes, dried and kept for use. By this process it became what was called gesso sottile, though the term is also applied to the similar preparation of whiting, to be mentioned presently. As to its use, it is directed to “Put some cakes of gesso sottile into a pipkin of water and let them absorb as much as they will. Grind it fine, mix it with fine glue in a pipkin, put the pipkin in water so that it becomes hot but does not boil, for if it did it would be spoiled.”

A very important point is the thorough slaking and tempering of the plaster, which continues to improve the longer it is kept. The glue that was used was made from hides, size being made from the fine kinds of skin, vellum and parchment, as the finest kind is made now. Fish glue was also used from very early times.

Very useful gesso is made with whiting (calcined chalk) instead of the plaster. The latter is said to be tougher, but whiting is certainly easier in working. The whiting should be soaked in water for at least twenty-four hours (like the preceding preparation this kind of gesso is all the better the more thoroughly it is prepared), and mixed in a vessel, with the fine thin glue, the whole being placed in a saucepan of water and kept hot. By keeping the pot of gesso in the water while it is being used it will be kept liquid for some time (though the top will skin over rather soon) and it may be remelted by again heating it from time to time. I find ordinary gelatine a good adhesive and melt it into the consistency of a not too strong size before adding it to the whiting, together with a few drops of oil or glycerine as a preventive from cracking. The gesso is best used with a long-haired brush, such as those called riggers, from which it is allowed to flow in a blobby way, the lights being first loaded on and afterwards joined down by subsequent painting. It may at this stage be modelled to some extent, and for this a stiffish brush moistened with warm water is an efficient tool. When it is dry the gesso may be carved and shaped with knives and riffles with the same facility as plaster. It may then have a coat of gelatine (which should be very thin, as otherwise it will form a skin that is likely to blur detail), and the work is ready for painting or other treatment.

In the treatment of wooden shields in this way care should be taken that they are well seasoned, and unless they are sufficiently thick they should have transverse pieces at the back to prevent warping; a coat of gesso on the back is also useful for the same purpose. If the wood is well stopped by being sized several times and is slightly roughened the layers of linen or other keying material may be dispensed with.

Gesso work is well adapted for treatment in colour, and of this the quality may be much improved by the use of underlying metal, gold under red, and silver under blue. These metals are applied by the ordinary gilders’ methods and are then painted over. Very beautiful effects may also be obtained in monochrome on modelled gesso, when the gradations of tone may be made to help the relief and vary the colour.

Pyrography, or burnt word etching, is also employed in heraldic decoration, a notable instance being the series of shields on the fireplace of Lord Leven and Melville at Glenferness. An example of this method of work is shown in Fig. 204, a fanciful composition designed for the door of a cabinet.

In arranging a scheme of heraldic decoration, the field of choice is a very large and varied one, from the simplest shield or badge on the frieze of a mantelpiece to the carefully planned series decoration of a whole building.