[Aztlan] 1930s facsimiles

[James Wechsler]

Can anyone recommend a source for the technical processes used in Mexico to publish isolated figures from codices during the 1930s? For instance, would the Chalchiuhtlicue on the cover of Caso's 1937 Religion of the Aztecs (and the black line reproductions of deities inside) have been photomechanically reproduced from the original (or facsimile) codex or did artist/technicians typically redraw the figure?

Thanks very much.

James Wechsler