The 2./ is mostly without any silver mirroring, fading, etc because the
process don't use any fixing chemicals, so (the remainder of) it cannot to
cause a silver degradation, and the picture material is often silver-sulfide
(also as a result of the process).
The 3./ usually has strong sharpness problems around the edges or
on the whole picture. Often there is a black "frame" around the picture.
Because the negative is existing more than one copies are possible.
As I know this process is in the practice recently also, in some poor
(exotical) countries. I have dates and photographs from these photographers
from the last years (I mean pictures where the master and the camera are
visible).
- Balint Flesch - Archaist/conservation photographer. - Budapest/Hungary. -