This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
The commonest transparent material is glass, and the polish, smoothness, and hardness of its surface adapt it well to the process. The operation is performed on the back of the sheet of glass, and this must be borne in mind with reference to the reversed position of the pattern. The surface to be gilt is thoroughly freed from adhering grease, etc, by rubbing with whiting, and the latter is removed by the aid of a silk cloth. Adhesion of the leaf is secured by simply moistening the surface of the glass with the tongue or the breath. When it has become attached and has dried, it is breathed on again, pressed all over with a pad of cotton wool, then warmed by the fire, and finally rubbed with dry clean cotton wool to bring up a polish. Next, on the gilded ground is marked the pattern which is to be exhibited, and such portion of the leaf is fixed by a coat of Brunswick black or of japanners' gold size containing a pigment such as yellow ochre, which is allowed to dry quite hard before proceeding to rub off the leaf from the portions which are not to be gilt. This rubbing off is done with pieces of wet cotton wool, the hand being meantime held off the work by a strip of wood supported across it at a suitable elevation.
If the pattern is to be made up of different kinds of leaf (deep and pale golds and silver), each kind is applied in turn, in the same manner, all over the unoccupied space, and rubbed out where not wanted. The background is finished by a coat of paint or bronze powder, the latter being rubbed with a "bob" upon a layer of varnish. The preliminary fixing of the leaf may be done with a water size, such as already described, if desired; this takes longer to dry, and, if allowed to get too dry, holds so firmly that it is difficult to remove the superfluous leaf.