Re: Dry Plate Speed & Shelflife

I was the one who asked the questions in the first place. I just want
to shoot glass plates without having to carry a darkroom with me as in
the wetplate process. In the real world (or mine at least) I don't
always know in advance the particular day in which I'll be able to go
shoot, so the keeping qualities (a few days) of a dry plate are
important to me. Maybe after I print out all the information that
these posts have given me, I can wade through and figure out what to
do.
thanks everybody!
Robert Newcomb
On Mar 7, 2005, at 5:45 AM, Bill William wrote:

>>> Ryuji, frankly, I am absolutely not keen on
>>> competing with your semi-professional
>>> (non reduction sensitized) silver halide
>>> emulsion.
>
>> As far as I know, this thread was about the speed
>> and other characters of color blind dry plate >emulsions
> from early years of silver-gelatin >process, of course for
> pictorial photography >applications. It wasn't about
> holography
>> or about how to make emulsions.
>
> No Ryuji, the original question was about making
> emulsions... you just weren't paying attention. (again!)
>
> "I've been interested in making my own..."
>
> Wern't you the one who expanded the subject away from the
> needs of the poster?
>
> The original post had these 2 questions:
> 1. Is their a component (bromide?) or procedure that will
> make a hand poured dry plate at least as fast as wet
> plates?
>
> 2.Is their a means of extending this shelf-life to a
> couple of weeks or at least something more the a few
> days?
>
> You expanded the subject and yet I do not see a really
> good response in there.
>
> The initial emulsions before 1873 are not even to be
> considered in my opinion. At the start there were wet
> plates that were fasrter, later there fewer and fewer wet
> plates that were faster that dry gelatin emulsions.
>
> The question is about wet plate speed that one gets today
> and dry plate (gelatin) that the poster is either going to
> buy or is going to make. The answer to the question is
> that he will be able to make dry plates faster than the
> wet plates if he is serious about doing the work... abnd
> he should not WORRY about the speed.
>
> If he wants to go the commercial way, since they are
> mostly chlorobromide (not all bromide as Ryuji seems to
> belive) he may have to either sensitize and or digest for
> more speed, (poster... this means cook your emulsion) or
> use color sensitization methods. There are other methods
> but we won't even get into those here. Details are
> availible when needed but now the problem appears to be at
> the "what if" level.
>
> If he wants to make his own, then he shoud go the Silver
> Bromoiodide route.
>
> The second question is strange.
> NO ONE should be having storage problems of just a few
> days... with home made OR commercial emulsions...
>
> the most likely source of cause of these problems are
> 1. too much heat during ANY stage of melting, coating,
> storage, etc.
>
> 2.
> Too much safelight exposure. or any UNsafelight exposure
> (poor storage methods etc.)
>
> 3.
> use of unsafe wrapping materials or methods, or other
> sourches of contamination prior to or during processing.
>
> "Is their a means of extending this
> shelf-life to a couple of weeks or at least something more
> the a few days?"
>
> The answer is YES, be careful and use only safe materials
> and procedures!
>
> (If the emulsion IS for some reason void of stabilizer,
> stabilizer can be added.)
>
> IMHO, the poster shoud relax, do something, then come back
> when he/she has a real, not a "what if" problem.
>
> Ray Rogers
>
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Received on Mon Mar 7 08:34:04 2005