Hmm, I could be wrong but I always figured that Hurrell originally shot to whatever (ortho?) film was available, made paper internegs and retouched them heavily. Many of the images have that graphical look.

One interesting thing about these turn-of-the-century photographers- Hurrell, Steichen, Edward Weston, Cunningham et al, is that some of them modified their style as the more modern materials became available, others didn't.