[pure-silver] Re: Contrast grades
- From: "BOB KISS" <bobkiss@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Fri, 26 Jul 2013 16:48:07 -0400
DEAR MARK,
Fasten your seatbelt because, when Richard gets home from work,
he will give you a thorough description of the methods used to determine
paper contrasts for both graded and VC paper.
However, in summary, although there are standards of how
manufacturers are supposed to determine contrast of their papers, the
reality is that, from manufacturer to manufacturer, there are significant
variations of the contrast of both graded paper and VC papers for each
"number" claimed by them.
As long ago as Adam's books, The Print and The Negative, he talked about the
significant variations of contrast of #2 papers from manufacturer to
manufacturer. Recall that his zone system was based on trying to produce a
neg that print nearly perfectly on a "middle" contrast paper and he aimed
his process at #2 contrast graded paper.
I pass the scepter to Richard.
CHEERS!
BOB
_____
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Sauerwald Mark
Sent: Friday, July 26, 2013 2:09 PM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Contrast grades
I understand how a higher number for the contrast of a paper, or for
variable contrast papers, using a filter for the higher grade results in a
higher contrast print. What I am wondering is if there is any objective
measure of what a contrast grade of 'N' is. If I use contrast grade 3
paper from one manufacturer, will I see the same contrast as if I use grade
3 from another manufacturer?
I imagine that plotting the exposure vs density you would be able to measure
the slope of the curve at some point (perhaps when the density is at a
predefined level,) and the steeper the slope, the greater the contrast - and
you could define the contrast grades by defining this gradient for each
grade has that been done? If so, where is it documented?
Mark
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