[pure-silver] Re: Contrast paper developer
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Fri, 10 Aug 2007 12:57:39 -0700
----- Original Message -----
From: "Ibrahim Pamuk" <ibrahim.pamuk@xxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, August 10, 2007 3:02 AM
Subject: [pure-silver] Contrast paper developer
Hi,
I have recently start using Durst M805 enlarger which is
diffused light type. My previous one was condenser based
enlarger. I found I need more contrast than before. This
ends with I have to work with 4.5 or 5 grade most of the
times. I plan to test a high contast developer for printing
for this reason. Can you recommend any formula? I used to
prepare D72.
Regards
Dave Valvo's advice is the best. The contrast difference
between a diffusing enlarger and the usual partially
diffusing condenser enlarger (a condenser with a large
diffuse lamp) is about one paper grade. The contrast yielded
by the development instructions for films varies. Kodak's
charts give contrast suitable for diffusion printing on
normal grade paper, Ilford instructions are compromise times
halfway between diffusion and condenser values. For most
films the difference in development time is about 30% for
one paper grade, for tabular grain films like T-Max or Delta
films its about 20%. The difference in required exposure is
about 3/4 stop for each paper grade change in contrast.
The effect of the developer on paper contrast is
minimal, for many modern papers it is nil. Paper is
developed to "completion" that is, to the highest contrast
its capable of. This is so that the maximum black will be
reached. Film can be varied in contrast by changing
development time because normal negative films are only
partially developed. This effect is just not possible for
paper.
I find negatives developed for diffusion printing will
print fine on a condenser enlarger using about Grade-1
paper. Since I use mostly a condenser enlarger I generally
reduce development somewhat from the chart values.
I suspect Dave is right about the filters in the
enlarger being faded.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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