Re: more dag questions

thanks for all your dag ideas- Stu
  ----- Original Message -----
  From: Phillip Murphy
  To: alt-photo-process-l@sask.usask.ca
  Sent: Saturday, January 10, 2004 11:17 PM
  Subject: 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 Sun Jan 11 11:54:48 2004