 Once he had made corrections, the "tlacuilo" applied a heavy black ink over the drafting black ink, but it is still visible in places.The red draft lines were never painted over.Some of the erasures the "tlacuilo" made are still evident.Angela Herren Rajagopalan, a scholar of pre-Columbian Mesoamerican art, believes that the "tlacuilo" worked all at once rather than folio-by-folio.