Here I tried to get the color better by cutting up the color areas and using HVS adjustment in Photoshop to colorize them. Can't rember were the duotone is... seems like spot coloring a duotone would be best. Back when we were using .gif images for the web there was a way to force and index color image into a custom palette but I can't remember how it was done... does anyone remember?

Why were pulp covers those colors? They used cheaper colors then the process colors for the seperations? They were four color sepaprations right? Just with ochre, red oxide and prussion blue instead of CYMK?

Thanks for the links DP... I'll go check!!!