[pure-silver] Re: HC 110 lament
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Sun, 30 Mar 2014 11:07:09 -0700
----- Original Message -----
From: "Gerald Koch" <gerald.koch@xxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Sunday, March 30, 2014 7:17 AM
Subject: [pure-silver] Re: HC 110 lament
Sulfur dioxide is nasty stuff. It produces asthma like
symptoms and can lead to pulmonary collapse. I think that it
is meaningful that in the entire existence of HC-110 no
company has tried to make a true copy of it even though a
similar formula is given in a patent. The reason I think is
the difficulty involved. Ilford makes something somewhat
similar but it contains water and has an inferior storage
life.
Since Kodak designed HC-110 to gives results as close as
possible to D-76 the latter is an obvious substitute. The
following site has some excellent information,
http://www.covingtoninnovations.com/hc110/
Jerry
Its worth reading the patent. It is written in much
clearer English than most patents and explains a number of
things about HC-110. It is USP 3,552,969
I don't think the chemicals referred to are plain
sulfur dioxide but rather a compound containing sulfur
dioxide. I have not read the patent thoroughly but it does
seem to have some information on the kinds of chemicals
involved and the reason for their use. I have also not read
any of the patents referred to.
D-76 is a good, general purpose, developer especially
if the buffered version is used. However there are other
developers that may be more satisfactory for some uses such
as Xtol or Perceptol (now that Microdol-X is gone).
A word about Kodak: There was an enormous world-wide
market for photographic material for generations. That
market shriveled up very quickly with the introduction of
low-cost electronic photography. AGFA decided early to
abandon that market. Kodak has held on for longer but the
very size of the original business pretty much doomed it
when the market shrunk. I think Kodak subsidized many of its
operations over the years including the research laboratory
and many special purpose products. There is no longer the
capital to indulge that so it had to be dumped. I don't
know how much longer Kodak will continue to make any
conventional photographic products but the recent
announcement by Paramount Pictures Corp that it was no
longer releasing feature pictures on film is a good sign
that the time may be short. Ilford has picked up the
photographic film business that remains. It is a much
smaller company and was flexible enough to indulge what must
be considered a niche market. I don't know much about Fuji,
they seem to be continuing to make color film and some B&W
products. I think they are less dependent on the theatrical
motion picture business than Kodak is but am not sure about
that.
I don't think conventional photographic products will
disappear any time soon but the selection of products has
obviously shrunk and, I am afraid, will continue to shrink.
--
Richard Knoppow
Los Angeles
WB6KBL
dickburk@xxxxxxxxxxxxx
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