It is to be hoped that some system of examining and hall-marking leather by some recognised body, may be instituted. If librarians will specify that the leather to be employed must be certified to be manufactured according to the recommendations of the Society of Arts Committee, there is no reason why leathers should not be obtained as durable as any ever produced. This would necessitate the examining and testing of batches of leather by experts. At present this can be done more or less privately at various places, such as the Yorkshire College, Leeds, or the Herolds’ Institute, Bermondsey. In the near future it is to be hoped that some recognised public body, such as one of the great City Companies interested in leather, may be induced to establish a standard, and to test such leathers as are submitted to them, hall-marking those that come up to the standard. This would enable bookbinders and librarians, in ordering leather, to be sure that it had not been injured in its manufacture. The testing, if done by batches, should not add greatly to the cost of the leather.
On the question of the qualities of an ideal bookbinding leather the committee report:—
“It is the opinion of the committee, that the ideal bookbinding leather must have, and retain, great flexibility.... (It) must have a firm grain surface, not easily damaged by friction, and should not be artificially grained.... The committee is of opinion that a pure sumach tannage will answer all these conditions, and that leather can, and will, be now produced that will prove to be as durable as any made in the past.”
The committee has so far only dealt with vegetable-tanned leather. I have used, with some success, chrome-tanned calfskin. Chrome leather is difficult to pare, and to work, as it does not become soft when wet, like vegetable-tanned leather. It will stand any reasonable degree of heat, and so might perhaps be useful for top-shelf bindings and for shelf edging. It is extremely strong mechanically, but without further tests I cannot positively recommend it except for trial.
While the strength and probable durability of leather can only be judged by a trained leather chemist, there remains for the binders selection, the kind of leather to use, and its colour.
Most of the leather prepared for bookbinding is too highly finished. The finishing processes add a good deal to the cost of the leather, and are apt to be injurious to it, and as much of the high finish is lost in covering, it would be better for the bookbinder to get rougher leather and finish it himself when it is on the book.
The leathers in common use for bookbinding are:—
- Goatskin, known as morocco.
- Calf, known as calf and russia.
- Sheepskin, known as roan, basil, skiver, &c.
- Pigskin, known as pigskin.
- Sealskin, known as seal.
Morocco is probably the best leather for extra binding if properly prepared, but experiment has shown that the expensive Levant moroccos are nearly always ruined in their manufacture. A great many samples of the most expensive Levant morocco were tested, with the result that they were all found to contain free sulphuric acid.
Calf.—Modern vegetable-tanned calf has become a highly unsatisfactory material, and until some radical changes are made in the methods of manufacturing it, it should not be used for bookbinding.