Re: physical developers

From: Richard Knoppow ^lt;[email protected]>
Date: 08/24/04-11:28:03 PM Z
Message-id: <001001c48a64$4dca4200$7efb5142@VALUED20606295>

----- Original Message -----
From: "Bill William" <>
To: <>
Sent: Tuesday, August 24, 2004 9:58 PM
Subject: Re: physical developers

> RK wrote:
> > Henry found that [grain] was no finer, and sometimes
> coarser, than D-76.
> to which MARTINM wrote:
> > For Lippmann emulsions physical developers may have
> > some advantages though.
> > They are able to produce grain sizes smaller than
> > 10nm...
> Yes, Martin, This is true!
> And I think 10 nm is smaller and thus finer...than
> whatever else was mentioned.
> Additionially, the time alloted to physical development is
> an important issue. I asked Richard for the ref. about the
> modern claim of no physical development occurring in
> ordinary processing... perhaps he was thinking about
> Richard Henry's book....
> But in general, considering the usual time required for
> physicall development, I never assumed that physicall
> development played a major role in production of image
> silver under ordinary circumstances... However under the
> correct circumstances, physicall development can be used
> to create extreamly small metal clusters... suitable in
> fact for holographic and very likely, lippmann images.
> While it may not play a major role in creation of image
> silver, that it doesn't occur is curious to me and I would
> like to hear more on the subject.
> My original curiosity was actually about the comparative
> speed of physical developing formulas...
> Anyone have any ideas for increasing the speed of physical
> development?
> (Martin has already mentioned gelatin hardness as one
> possible variable)
> Does anyone know of any ultra fast acting physical
> developers ?
> Ray
   I would have to search a couple of books. This may be in
Haist or in Mees and James. I will try to find the source
but my memory is even in the older books like Mees
_Principles of the Photographic Process_ some doubt is

Richard Knoppow
Los Angeles, CA, USA
Received on Tue Aug 24 23:28:25 2004

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