The pottery tradition in Peru’s central and northern coastal states emphasizes single color vessels, especially black, gray, or brown as occurs in Chavín.
Later, this aesthetic was replaced by the use of more colors, especially in cultures like the Moche. Still later, however the Chimú potters went back to making mostly or gray vessels, returning to the old tradition.
With this archaism, they probably sought to give their works some of the prestige associated with the past.