Re: Dry Plate Speed & Shelflife

The method described at http://cabd0.tripod.com/holograms/id3.html might be
easily adapted to purely photographic applications. Since it involves
ascorbate reduction sensitization as well the possibility of TEA
(triethanolamine) hypersensitization, reasonable speed might be expected.

That method actually goes back to the early days of photography (Talbot).
Incidentally, as early as 1850 Poitevin modified this process for the making
of gelatin coated silver halide emulsions on glass plates...

Martin

----- Original Message -----
From: "Robert Newcomb" <newcombr@uga.edu>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Tuesday, March 01, 2005 5:53 PM
Subject: Dry Plate Speed & Shelflife

> I've been interested in making my own glass dry-plates to shoot in
> camera - I like some of the "errors" introduced from hand poured
> emulsions.
> A couple of questions for all you knowledgeable people out there.
> 1) I have read that the speed of early dry-plates was about 7 stops
> slower then the wet -plate process in use at the time. While I'm
> certainly not trying to shoot action sports shots, we're talking Very
> slow here. I have heard that the bottled silver emulsions have an in
> camera speed of about ISO 1/2- maybe 1.
> Is their a component (bromide?) or procedure that will make a hand
> poured dry plate at least as fast as wet plates?
> 2) I have also understood that early dry plates (hand poured) had a
> useful shelf-life of only a few days or a week after being made in
> which one must expose them. Is their a means of extending this
> shelf-life to a couple of weeks or at least something more the a few
> days? I'd hate to make them and then not be able to go out shooting
> the next day so the plate spoil.
> I understand that commercially prepared plates later overcame these
> factors but what is possible of the home brewer?
>
> Thank you,
> Robert Newcomb
>
Received on Wed Mar 2 04:32:14 2005