Digital BW, The Print

I am currently printing a portfolio for a friend. She photographed nudes on
35 mm Tri-X. The PiezoTone prints look posterized in the midtones (like a
print that was not totally fixed) , the transitions from the midtones to the
darker skin tones are much too hard. Because I just started with PiezoTone I
thought it was my fault and checked everything again and again with no
improvements. But today I tried Woolfs workflow and the Epson driver. And
voila: the problems are solved although the highlights are not as dotfree as
with the Piezo driver (under a magnifier). But thats not a problem with
grainy negatives...

In my opinion the holy 21 step wedge test does not show the real problems
unless you are exclusively working with large format cameras and ASA 100
films or digital cameras. My assumption now is that the piezo driver has
difficulties with interpreting noisy pixels. And you all can proof this if
you use the 21 step wedge and add a small amount of noise that is more or
less in the range of a 35 mm 400 ASA film. Then the tonal transitions being
smooth when printing the step wedge straight become totally different. In
the range of 35% to 50% you can find posterization, from 50% to 60% there is
an artificial lumpy structure not related to the noise, from 65% to 70%
again some posterization, from 70% to 100% again a too noisy lumpy structure
(but less pronounced than in the 50 to 60% range). Making the same
experiment with the Epson driver and Woolfs workflow does not show this
phenomenon.

If it is the grain that disturbs the piezo driver interpretation of density
then this would explain why some people reported problems with posterization
and bad skin tones and others did not mention it at all although the product
is long enough in the market (btw: who tested fading before launching
PiezoTone?? Should have been noticed before as well.).

Any comments?

Peter Baumbach
Fine Art Photography Munich



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