sepia

sepia. A brown pigment made from the ink of cuttlefish and other marine creatures. It is mentioned by Roman writers and was perhaps used in the ancient world for writing, but it was evidently not until the late 18th century that it was much used in art—for ink drawings and, because of its semi-transparent quality, in washes. When first applied to paper, sepia is a warm black, but it gradually turns reddish brown. It is more opaque than bistre, which it tended to replace in the 19th century, but it can be difficult to tell them apart (and to distinguish them from other brown pigments, especially as different types of ink were sometimes mixed). The terms tend to be used fairly loosely.