Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

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sepia inks

Inks that are compounded from the dark pigment discharged by the common cuttle-fish and other cephalopods, family Sepiidae, in order to mask retreat. The effect of this fluid is somewhat remarkable, in that 1 part ink in 1,000 parts of water is sufficient to make the latter opaque. It was used as an ink in ancient Rome, but is little used today except as an artist's coloring. The dried ink is pulverized and boiled with alkali, which is subsequently neutralized with acid so as to precipitate the pigment. The pigment is then washed, dried, and incorporated with oil. The main feature of this process, with regard to permanency, is the amount of acid used to precipitate the pigment, because acid in ink is as detrimental to paper, as is acid in the paper itself. Although sepia inks are reasonably permanent in dull light, they tend to fade rapidly when exposed to bright natural light. (20 , 143 )

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