I imagine that few of us these days process enough b/w film to make a
replenished system practical, since they thrive on volume. When I was at Kodak
I ran a 3-1/2 gallon replenished sink line that used first D-76 and, later,
HC-110. But in those days (late 1980s on) we shot a great deal of 4x5 b/w. For
a number of reasons that system was replaced with a Wing-Lynch 4E, but that's
another story.
XTOL is the only developer I know of that replenishes with itself (an oddity
when it was introduced in the '90s.) Edgar Praus in Rochester does a great job
in his lab using replenished straight XTOL. As far as manufacturers offering
replenishers to go along with their developers, it's for a reason. Many, many
tests in the research lab proved that it works.
In my personal photography, I've long used one-shot developers, as much for
convenience as anything else.
Mark Sampson
-----Original Message-----
From: `Richard Knoppow <dickburk@xxxxxxxxxxxxx>
To: pure-silver <pure-silver@xxxxxxxxxxxxx>
Sent: Fri, Jul 14, 2017 3:05 pm
Subject: [pure-silver] Re: Replentishing With New Developer
What you suggest is given as the recommended method for many modern
developers, for instance T-Max RS and Xtol. I think it would work for
either D-76 or DK-50 provided the correct amount of developer was
replaced. For any replenishment system to work you really should
establish the rate of replenishment by sensitometric means but that is
over kill for most of the sort of work we do. For photofinishing (does it
exist any more?) or motion picture processing it is essential but probably
not for small home labs. I think the reason the replenisher formulas have
a lot of alkali in them is to compensate for the accumulation of bromide
and iodide in the developer. However, while average density and film
speed can be held fairly constant the shape of the film curve may change
as it does when more restrainer is added. I need to find my copy of
Haist's book because I think he deals with this. Its in storage (I think I
know where) and I hope the silverfish haven't gotten to it.
On 7/14/2017 7:45 AM, Tim Daneliuk wrote:
When dealing with D-76 or DK-50, is it really urgent that one use the
replentisher chemistry? Why can't I just use fresh devloper (at the same
dilution) and top up the working developer with, say, 1oz of fresh dev
every use?
--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
WB6KBL
