Re: physical developers

From: Bill William ^lt;[email protected]>
Date: 08/24/04-10:58:42 PM Z
Message-id: <>

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

(Martin has already mentioned gelatin hardness as one
possible variable)

Does anyone know of any ultra fast acting physical
developers ?


Received on Tue Aug 24 22:58:52 2004

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