[pure-silver] Re: Multigrade 1:9 developer vs Dektol 1:2
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Wed, 22 Feb 2012 18:16:48 -0800
----- Original Message -----
From: "Eric Nelson" <emanmb@xxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Wednesday, February 22, 2012 5:37 PM
Subject: [pure-silver] Re: Multigrade 1:9 developer vs
Dektol 1:2
I did a little more research and found that at the next
dilution listed, which is 1:14, the development needs to be
increased as expected, as well as the capacity is
diminished. Perhaps a false economy indeed, but along those
same lines, I do get good blacks in Ansco 115 diluted 1:5
but developed for 2-2.5 mins. Certainly as black as needed
anyway! :) So perhaps for RC prints, which is a relatively
quick development, 1:14 would be fine but there won't be
much more of that done here anyway.
Thanks Richard.
e
I am pretty sure the RC papers that develop quickly have
developer-incorporated emulsions. This was originally to
allow the paper to be used in an activator type rapid-access
machine. I am not sure anyone uses these any more but I
think some RC emulsions still have developer in them. The
developer-incorporated papers develop in about half the time
of a conventional emulsion weather coated on RC or fiber
paper. Most conventional papers take somewhere between one
and two minutes for complete development. The cold tone
papers like the late-lamented Kodabromide, would develop in
one minute, warm tone papers took about two minutes. These
are minimum times and extending them by about fifty percent
was common. Development time can compensate for exposure
over a rather narrow range. Despite the extensive literature
on control of contrast by development the contrast of paper
is pretty much built into the emulsion so that variation of
exposure and development has very little effect on it unless
one is willing to accept under-developed blacks. This is a
different situation from pictorial film where the emulsion
is seldom developed to "completion", as a result one can
vary the contrast of the image over a rather wide range by
adjusting exposure and development.
I rather think you already know this stuff but some
readers of this list may not.
--
Richard Knoppow
Los Angeles
WB6KBL
dickburk@xxxxxxxxxxxxx
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