Complex sentence: The term's popularity spread east in the late 1970s and 1980s, however its use began to decline amongst colour artists in the 1990s and is seldom used in 2000, replaced by more accurate terminology such as polychrome.
Split into simpler sentences: The term's popularity spread east in the late 1970s and 1980s, but began to decline in the 1990s. It was seldom used by 2000, replaced by more accurate terminology such as polychrome.