Re: more dag questions

Stuart Plotkin wrote:

> Do most of you making Daguerreotypes use the Becquerelmethod or do any
> use the mercury process.
>
> I'm sure that you'll find those who work either of those techniques or
> both. There are also those who are using a vacuum
> chamber method that has been modernized by John Hurlock.
>
> Is it true that the mercury process gives a better result, or does it
> depend on who you ask?
>
> Better is relative to the results that you are attempting to achieve.
> Each method expresses it's own unique visual syntax.
>
> Has anyone tried just dipping the exposed plate in mercury, that would
> be safer- I assume this has been tried and didn't work.
>
> This would expose you to a greater surface area of mercury's
> sublimation and would not be inherently safer.
> Also, one can easily over mercurialize the image on the Daguerreotype
> plate so you need a way to control the amount of
> mercury that adheres to the latent image sites.
>
> What would happen if you use a conventional developer?
>
> You can create images on the Daguerreotype plate using developing
> agents,
> however, they will not have the optical properties of the
> Daguerreotype.
>
> Would you end up with a negative instead of a positive?
>
> You would have a negative image. Some have coated the plates and
> stripped these images from them.
>
> Does anyone know why with the mercury process do you coat the plate
> with iodine, bromine and iodine but in the Becquerelprocess you use
> only iodine? Doesn't the bromine make the plate more sensitive?
>
> Bromine is an accelerator of the process. All of the halogens are
> accelerators. Cholorine was often used and Flourine
> was used but difficult to control. Every possible combination of the
> halogens was experimented with in various
> combinations back in the day. Bromine was found to be the most
> practical for the working Daguerreotypist and that
> holds true today. It's true that most people only use Iodine for the
> Becquerel development, however, Bromine can
> be used along with Iodine as well but the results are not as good.
> Also, it requires that you use the deep red filtration
> when using an accelerator for Becquerel as opposed to the deep yellow
> when Iodine alone is used.
>
>
> i was talking to my old chemistry professor at college about mercury
> fumes and perhaps constructing a closed system that does not allow any
> mercury vapor to be released, or perhaps a distilling apparatus that
> cools and condenses the vapors to be easily collected. He also said
> that sulphur acts like a sponge and will soak up any mercury vapor and
> turn it into a harmless insoluble salt. What do you think?- Stu

There was such an apparatus built in the early 1850's: "Anthony's
Condensing Mercury Bath". There's no record of it being
used extensively. Zinc powder or flakes will amalgam with mercury
readily, thus it's use in mercury spill kits.

-Phillip
Received on Sat Jan 10 22:18:14 2004