Sepia is a reddish-brown color, named after the rich brown pigment derived from the ink sac of the Common Cuttlefish: Sepia officinalis L.
Sepia ink was commonly used as writing ink in Greco-Roman civilization.
It remained in common use as an artist’s drawing material until the 19th century.
There was a magazine for African-Americans called Sepia, which existed from 1947 to 1983.
In the late 1940s and early 1950s, R&B (Rhythm and Blues) music was called Race Music or Sepia Music.

Even before that, Sepia was used in a composition “Sepia Panorama” (aka “Night House”) by

Duke Ellington & His Famous Orchestra

rec. July 24, 1940. New York
RCA-Victor recording session at Studio 2

Rex Stewart, c; Wallace Jones, Cootie Williams, t; Lawrence Brown, Joe Nanton, tb; Juan Tizol, vtb; Barney Bigard, cl; Johnny Hodges, as, ss; Otto Hardwick, as, cl; Ben Webster, ts; Harry Carney, bs, cl, as: Duke Ellington, p; Fred Guy, g; Jimmie Blanton, b; Sonny Greer, d
 

 
In April 1939 Ben Webster became a member of Teddy Wilson’s big band and was its most important soloist, but a dream came true when he was offered a permanent job in Duke Ellington’s orchestra. He therefore left Wilson in January 1940 and went to Boston to play his first job with Ellington. (Actually he had subbed for Barney Bigard on two short occasions, in 1935 and 1936).

Webster stayed with Ellington until early August 1943, and it was during these years he gained national and international fame with recordings like Cotton Tail – which became his signature tune – Jack the Bear, Harlem Air Shaft, and Sepia Panorama …