[pure-silver] Re: HC 110 lament
- From: Gerald Koch <gerald.koch@xxxxxxx>
- To: "pure-silver@xxxxxxxxxxxxx" <pure-silver@xxxxxxxxxxxxx>
- Date: Sun, 30 Mar 2014 17:16:52 -0700 (PDT)
You're right that HC-110 does not contain sulfur dioxide but it does contain
the [U]addition product[/U] of diethanolamine and sulfur dioxide. Perhaps my
post was not entirely clear as to this point. It also contains the addition
product of hydrogen bromide and diethanolamine. Since there is no water in the
developer this is the only way of getting bromide and sulfite into the mix.
Jerry
________________________________
From: Richard Knoppow <dickburk@xxxxxxxxxxxxx>
To: pure-silver@xxxxxxxxxxxxx
Sent: Sunday, March 30, 2014 2:07 PM
Subject: [pure-silver] Re: HC 110 lament
----- 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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