<<
Peter Marshall says that you can make such a record on POP, others say you
cannot, over the full range of tones and challenged me to do so. As this is
not
what I was on about, I did not take up the challenge. >>
No, I said you can produce the range you said on quite ordinary multigrade
paper - and I have the step wedge print here as proof! (I ran out of
steps!) The point I was making is that it is NOT a matter of the range of
negative densities that can be printed that distinguishes (for example)
platinum from silver. If you can get it on a silver negative you can print
it on a silver paper.
The visual differences are more subtle and have to do with the shapes of the
characteristic curves and the paper surfaces and coatings and the actual
position of the image metal, its state of division etc.
Incidentally I understand the practice with large format photography in the
distant past was to give what we would regard very full exposure and
development. The negatives produced would be more like the ones that Terry
prefers (or thinks superior) for platinum and were printed by contact on
silver gelatine paper that was very soft by today's standards (Grade 0 or
below). Grain and sharpness were hardly of importance - and very dense negs
were no great problem.
Once enlargement became important photographers needed to rethink their
methods and aim for lower density, less grainy and sharper negs - and so
the need for the Zone system. It was _not_ a response to any problems of
silver gelatine printing paper and of course can be used with any printing
material or method which can produce consistent results. If you know the
characteristics of the negative that you need for _any_ process the Zone
system (or indeed the application of more rigorous sensitrometric methods)
will enable you to suit exposure and development to the scene to get these
results.
Peter Marshall
Fixing Shadows and elsewhere:
http://faraday.clas.virginia.edu/cgi-uva/cgiwrap/~ds8s/Niepce/peter-m.cgi