When she is not home spinning discs, out haunting music stores or cruising clubs, she makes paintings about fashion-conscious Japanese teenagers who want to look cool, black and American, much like their hip-hop idols. Known as the ganguro, these teenagers dress in funky clothes, dye and weave their hair into cornrows and darken their skin at tanning salons or with makeup. Ganguro, literally ''black face,'' has its roots in the mid's, starting with a desire among Japanese girls to emulate the popular, sun-tanned Okinawan singer Amuro Namie and the black British fashion model Naomi Campbell. Blige, the Big Tymers and others. Brown, 37, first learned about the ganguro while studying painting at the San Francisco Art Institute in the late 's.