Notes on Bookbinding for Libraries

by John Cotton Dana

Another form of deterioration, more noticeable in the newer books, renders the grain of the leather liable to peel off when exposed to the slightest friction. This is the most common form of decay noted in the most recent leathers.

Decay is caused by both mechanical and chemical influences. Of the latter some are due to mistakes of the leather manufacturer and the bookbinder, others to the want of ventilation, and improper heating and lighting of libraries. In some cases inferior leathers are finished (by methods in themselves injurious) to imitate a better class of leathers, and of course where these are used durability cannot be expected. But in the main the injury for which the manufacturer and bookbinder are responsible must be attributed rather to ignorance of the effect of the means employed to give the leather the outward qualities required for binding, than to the intentional production of an inferior article.

Embossing leather under heavy pressure to imitate a grain has a very injurious effect.

The shaving of thick skins greatly reduces the strength of the leather by cutting away the tough fibers of the inner part of the skin.

The use of mineral acids in brightening the color of leather, and in the process of dyeing, has a serious effect in lessening its resistance to decay.

Quite modern leather dyed black seems, in nearly all cases, to have perished, although old black morocco (sixteenth, seventeenth and eighteenth centuries) in good condition is not uncommon.

In a very large proportion of cases the decay of modern sumac-tanned leather has been due to the sulphuric acid used in the dye bath, and retained in the skin.

Tobacco smoke has a darkening and deleterious effect on leather bindings.

Light, and especially direct sunlight and hot air, possess deleterious influences which had scarcely been suspected.

Gas fumes are the most injurious of all the influences to which books are subjected, no doubt because of sulphuric and sulphurous acid they contain. They are especially injurious to books on the upper shelves of a high room.