Encyclopedia
sepia
dyestuff, coloured brown with a trace of violet, that is obtained from a pigment protectively secreted by cuttlefish or squid. Sepia is obtained from the ink sacs of these invertebrates. The sacs are speedily extracted from the bodies and are dried to prevent putrefaction. The sacs are then dissolved in dilute alkali, and the resulting solution is filtered. The pigment thus obtained is precipitated with dilute hydrochloric acid and is then washed, filtered, and dried. The chemically inert pigment is fairly permanent and is used as a drawing ink and as an artist's watercolour, particularly in monochrome
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