Book pages can become yellow with age or when exposed to smoke. Ink-spots can contribute to ruining them too. To bring them back to their original splendor, our nineteenth century ancestors used this trick:
PROCESS OF BLEACHING OLD BOOKS AND COPPER – PLATE PRINTS WHICH ARE BECOME YELLOW BY AGE, SMOKE, &C.
The process now practised for bleaching these articles is as follows:—Take off the binding of the book, unsew the book and separate the leaves, place them in a shallow leaden pan, with slips of common window-glass interposed between them, so that the leaves lie horizontally without touching each other.
Or a still better method is the following :—Make a wooden frame of about the size of the leaves to be bleached, and having placed upon it the slips of glass, let the leaves be placed upon the glass perpendicularly, about a line distant from each other. This being done, pour into the vessel the bleaching liquid, which is made by dissolving one part by weight of oxymurate of lime in four parts of warm water, and suffer the articles to be immersed in it for twenty-four hours: it may then be rinsed in soft water.
By this process the paper will acquire a whiteness superior to what it originally possessed. All ink-spots, if any were present, will be removed; but oil and grease spots are not effaced by it. — Copper-plate prints bleach more easily than letter-press.
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