Re: Anyone given Color Daguerreotypes a try?-reply

----- Original Message -----
From: "Robert W. Schramm" <schrammrus@hotmail.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Saturday, June 19, 2004 7:55 AM
Subject: RE: Anyone given Color Daguerreotypes a try?-reply

>
> VERY interesting! I have never heard of this process
although I was aware
> that there were claims for a color daguerreotype process
that some thing is
> a sham. One could easilly have some copper plates made.
The only problem
> might be in obtaining hydrogen sulfide. As I recal
sulfuric acid on copper
> produces this gas. Does anyone know for sure? Perhaps that
would not be the
> best way to produce it. Does anyone have any additional
info about this
> process?
>
> Thanks Jeff and best wishes,
> Bob Schramm
> Check out my web page at:
>
> http://www.SchrammStudio.com
>
    Hydrogen sulfide is what gives sepia toners their
"rotten egg" odor. Its very easy to produce from sodium
sulfide and any acid.
    I am wondering if the claim is for images in natural
color. Its possible the writer meant that the image was
toned in various colors dependant on the density, something
like what would now be called split toning. It seem to me
from my limited knowledge of chemistry that the image would
be composed of silver sulfide as it is in sepia toned silver
prints. The color of a silver sulfide image is not
necessarily the reddish brown of sepia but can vary from
blue to red or yellow depending on the nature and size of
the sulfide crystals. Silver sulfide is very stable which
could account for the claim that the images are permanent.
However, since the hydrogen sulfide probably also tones any
silver halide left on the plate I wonder about the lack of a
fixing step. Perhaps the remaining halide tones to a
contrasting color. Very curious.
   About the only single emulsion color process I know of is
the Lipmann process. This relies on an interference pattern
in a very thin, extremely fine grain, emulsion. The Lipmann
process requires a mirror under the emulsion, Mercury in the
original process. I don't think that's what is happening
here.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com