1911 Encyclopædia Britannica/Sepia

SEPIA (Gr. σηπία, cuttlefish), a deep brown pigment obtained from the ink-sacs of various species of cuttlefish (q.v.). To obtain sepia. the ink-sac, immediately on the capture of the animal, is extracted from the body and speedily dried to prevent putrefaction. The contents are subsequently powdered, dissolved in caustic alkali, and precipitated from the solution by neutralizing with acid. The precipitate after washing with water is ready to make up into any form required for use.

Sepia-bone or cuttle-bone consists of the internal “ shell " or skeleton of Sepia officinalis and other allied species. It is an oblong convex structure from 4 to 10 in. in length and 1 to 3 in. in greatest width, consisting internally of a highly porous cellular mass of calcium carbonate with some animal matters covered by a hard thin glassy layer. It is used principally as a polishing material and for tooth powder, and also as a moulding material for fine castings in precious metals.