The lab I used to work for used Agfa PMT (Photo Mechanical Transfer) paper to make pure line positives on paper from artwork. The thin RC negative paper was black and was exposed using a process camera. This was then sandwiched emulsion to emulsion with a receiving paper and put through a simple machine with a monobath developer which put the two wet papers through rollers. They were peeled apart and the receiving paper would then have the positive image printed on it. As I remember, the black paper would show the negative, similar to how a Polaroid backing negative would appear. (Welcome to be corrected or more detail given about the process; this is only what I remember.) This was in the 80s and we never used this process for creative uses, though other films and papers in the Agfa graphic range worked well for lith and high contrast effects. As these materials were primarily for preparing artwork for reproduction, they fell out of use around this time as digital had revolutionised the printing industry long before it got hold of photography.