This is far more complicated than blind or antique work, so that it is better to practise upon some spare pieces of roan, calf, and morocco, before attempting to finish a book. Gold work is not more difficult than blind tooling, it is only more complicated. The different kinds of leather require such different degrees of heat, that what would fail to make the gold adhere upon one leather would burn through another.
The wet medium is again divided into 2 classes, one for non-porous and another for porous leather. Morocco is the principal of the non-porous leathers, with roan and all other imitation morocco. The porous varieties consist of calf of all kinds, russia and sheep.
The porous varieties must be paste-washed carefully, sized all over very evenly, and glaired once or twice; care being taken that the size and glaire be laid on as evenly as possible.
All this, although apparently so simple, must be well kept in mind, because the great difficulty is in not knowing the proper medium for the various leathers, and one book may be prepared too much, while another may have a deficiency. As a consequence one book will be spoilt by the preparation cracking, and the gold will not adhere to the other. By following the directions here given, the gold will adhere without much trouble, beyond the practice necessary in becoming accustomed to an accurate use of the various tools.
Suppose that a half-morocco book is to be neatly finished and lettered. Take a broad and narrow pallet of a suitable and proper size, work it against the bands in blind as a guide for finishing in gold. As the impression need be but very slight, warm the pallet on the gas stove but very little. Choose some suitable tool, as a centre piece to go between the bands. Work this also lightly on the back exactly in the centre of each panel, as truly as possible and perfectly straight. A line made previously with a folding-stick along the centre of the back will greatly assist in the working of a tool in its proper position. Wash the back with vinegar, and brash it well with a hard brush to disperse the moisture and drive it equally into the leather; some use paste-water for this purpose instead of vinegar. Paste-water has a tendency to turn grey in the course of time: this is avoided in using vinegar, which also imparts freshness to the morocco, and keeps it moist a longer time, very desirable in finishing.
The impressions made by the broad and narrow pallet and the centre tool are pencilled in with glaire; when dry, pencil in another coat; allow this again to dry, then rub them very slightly with a piece of oiled cotton wool. Take a leaf of gold from the book, and spread it out evenly on the gold cushion; cut it as nearly to the various shapes and sizes of the tools' as possible. Take one of the pieces of gold upon a large pad of cotton wool, greased slightly by drawing it over the head. (There is always a sufficient amount of natural grease in the hair to cause the gold to adhere to cotton drawn over it). Lay the gold gently but firmly on the impressed leather. See that the whole of the impression be covered, and that the gold be not broken. Should it be necessary to put on another piece of gold leaf, gently breathing on the first will make the second adhere.
When all the impressions are covered with gold leaf, take one of the tools heated to such a degree that when a drop of water is applied it does not hiss but dries instantly; work it exactly in the blind impressions. Repeat this to the whole of the impressions, and wipe the overplus of gold off with the gold-rag. The impressions are now supposed to be worked properly in gold; but if there are any parts where the gold does not adhere, they must be re-glaired and worked in again. A saucer should be placed near at hand with a piece of rag or a sponge and water in it, to reduce any tool to its proper heat before using. If the tool be used too hot, the gold impression will be dull - if too cold, the gold will not adhere. To use all tools of the exact degree of heat required is one of the experiences of the skilled workman.
The back is now ready for the title. Set up the words in a type-case, with type sufficiently large and suitable to the book. The chief word of the title should be in somewhat larger size than the rest, the others diminishing, so that a pleasant arrangement of form be attained. In order to adjust the length of the words, it may be necessary to "space" some of them - that is, to put between each letter a small piece of metal called a "space." Square the type, or make the face of the letters perfectly level by pressing the face of them against a flat surface before tightening the screw. They must be exactly level one with another, or in the working some of them will be invisible. Screw the type-case up, warm it over the finishing stove, and work the letters carefully in blind as a guide. Damp the whole of the lettering space with vinegar. When dry, pencil the impressions in twice with glaire. Lay the gold on and work them in gold.
But with lead type and a spring type-case (more suitable for amateurs on account of its relative cheapness, and the case fitting itself to the different sizes of the type) the latter must be warmed before the type is put in. The heat of the case will impart sufficient heat for the type to be worked properly. If the case and type be put on the stove, the type will probably be melted if not watched very narrowly. Hand letters are letters fixed in handles and each used as a single tool. The letters are arranged in alphabetical order round the finishing stove, and as each letter is wanted it is taken from the order, worked, and replaced. They are still very much used in England, but where several books are to have the same lettering, brass type is very much better. It does its work more uniformly than hand letters, however skilfully used.