Klaus
I agree with much of what you say. However on this list most of us are still
tied to silver gelatin - as a negative making process rather than a printing
process. In one of my comments I tried to summarise briefly the tonal
qualities which I think make platinum distinctive compared with silver
gelatin as a printing medium.
(One point where I would differ is you comment that we necessarily reduced
the number of tones in platinum. The number of tones is not really a
measurable entity in any case, but it is one of the choices we may make - if
you like by the zone system - on both silver and platinum prints.)
There are various tools we can use - such as step wedges. I think it is
important to realise what they do tell us and also their limitations.
Peter