Re: Daguerreotype/Cold-Mercury development

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From: Robert W. Schramm (schrammrus@hotmail.com)
Date: 03/19/01-04:39:18 PM Z

Manuel,

I have never heard of a cold mercury process so I cannot help you with that. The Becequerel process is very simple. I have never done it but have seen plates that were developed this way.They look OK to me but have a different color than a mercury developed plate and perhaps less contrast. For the Becequerel process, the plate is only fumed in iodine. The color of the plate is not the usual straw yellow but some other color which I forget. YThe plate is developed by exposing it to red light for several hours. I believe one way of doing this is putting a red filter (red glass) on top of the plate holder and putting it out in the sunlight and pulling out the darkslide.

The Daguerreian Society published a paper on the Becequerrel process in one of its annuals along with some color photos of Becquerrel plates. They are at 3045 West Liberty Ave., Suite 7, Pittsburgh,PA 15216

Bob Schramm

>From: Manuel
>Reply-To: alt-photo-process-l@sask.usask.ca
>To: alt-photo-process-l@sask.usask.ca
>Subject: Daguerreotype/Cold-Mercury development
>Date: Sun, 18 Mar 2001 05:56:24 +0100
>
>Hi all:
>
>John R. Hurlock in the article "Warming Up To Cold Mercury" (The Daguerreian Annual 1998) wrote:
>"...Where previously I had been developing using mercury, this time I decided to try using the Becquerel method of development as described in Gerard Meegan's article in the Daguerreian Annual 1991(1). But I found that getting the right color during the fuming process was a fustrating experience, and the exposure times appeared to be much longer than I had previosly experienced with hot-mercury development. Furthermore, I was frequently disappointed when a fog veil appeared at the end of the development process. after finally achieving a neutral-toned Becquerel plate, I found the appearance didn't satify me..."
>
>Bob Schramm ( article "How an Old Alternate- Process Printer from a Small Town in West Virginia Learned to Make a Daguerreotype" -Post-Factory # 4-) heat liquid mercury to about 175 ºF ,60 ºC, (daguerreotypes must be exposed to mercury vapor).
>
>Gerard Meegan wrote a Chapter (1, Becquerel- Developed Daguerreotypes) in the book " Coming into Focus: A Step-by-Step Guide to Alternative Photographic Printing Processes" by John Barnier (editor).
>
>+ Bequerel process develop plates without mercury vapor. No danger developer but very slower
>+ Hot Mercury, good developer but very dangerous and expensive (fume hood)
>+ Cold-Mercury development , good, less dangerous and more cheap that Hot Mercury ( a polycarbonate vacuum desiccator) and more fast that Becquerel process.
>
>My question: Is the Cold-Mercury developer the best alternative for Daguerreotype?. Do you have any experience about it?
>
>Thanks.
>
>Manuel Estébanez
>Spain
>
>

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