From: David Eastman (clearemulsions@yahoo.com)
Date: 10/09/02-02:55:35 AM Z
Thanks for this information! It is very interesting
indeed.
One question however...you wrote that "Rhodium, which
is a very bright white metal..."
Hummm, I have a gram of it... it is Rhodium chloride
(X H20) or something: it is in a sealed ampule...
under nitrogen as it is not stable in oxygen or
something... and it is very expensive! Oh, and it is
rust brown in color.
I had always assumed the compound I have and the metal
itself kind of looked and cost the same...
Did I assume too much?
Ray
--- Phillip Murphy <pmurf@bellsouth.net> wrote:
> Jeff Sumner is correct; various coatings have been
> attempted over the years with
> little success. Glass remains the preferred method
> of sealing a plate.
>
> However, I also deeply enjoy the pristine clarity of
> a naked plate... It is
> unique. The answer to your question lies in
> metallurgy. In the early days of
> the Daguerrian era , the use of the electro-galvanic
> cell (the battery) was
> widely experimented with. One clever technique was
> to copy relief objects, that
> were coated first with a conducting medium (usually
> a form of graphite), using
> copper. In these days, you would google
> "electroforming" as a search for
> information and find that a very fine copper "paint"
> is used for the conductive
> medium. (think...bronze baby shoes) In the early
> 1840's, realizing that the
> Daguerreotype plate has a relief surface, someone
> hit upon the idea of
> electroforming on the surface of the Daguerreotype
> with copper. When this was
> carried out until the copper had reached the
> thickness of a card, the copper
> plate was carefully removed and the result was that
> the Daguerreotype was
> replicated in all it's perfection. These plates
> were hailed at major
> exhibitions for their beauty and delicacy of tone.
> Very few examples can be
> found today. (as an aside: this is the very
> technique that Woodbury used in the
> original Woodburytype plate making) Also, very
> little energy is needed to
> electroform copper. A group of rechargeable "D"
> cells is plenty and you can have
> several plates forming at the same time using a
> several copper sulfate baths
> connected in series.
>
> Now this is how one thing leads to another: When
> you electroplate or
> electroform with copper, one thing you notice about
> copper is the variety of
> colors that the metal can assume under various
> conditions. A man by the name of
> Charles G. Page decided to exploit that quality by
> devising a way to "color"
> Daguerreotypes using varying thickness' and
> combinations of solutions of copper
> to create the colors. He was somewhat successful
> with this and I believe even
> had the method patented. These days, that technique
> is referred to as
> pen-plating.
> One thing Page discovered in his experiments is that
> when he electroplated an
> extremely fine coating of copper on the
> Daguerreotype surface, it brought more
> brilliance to the plate than even gilding does. The
> more interesting thing,
> however, is that it also had the property of
> "hardening" the surface of the
> plate. So much so, that it could be handled readily
> without damage. The story
> goes that he carried one around in his pocket for
> over a month without damage.
> A plate was kept open to the atmosphere for over a
> year without any apparent
> change. He even rubbed it with a tuft of cotton
> without damage..
> I've always felt that this technique might prove to
> be a great avenue for
> Daguerreotype experimentation.
>
> My choice would probably not be copper but perhaps
> Rhodium, which is a very
> bright white metal that creates a very tough
> surfacing.
> No time for experimenting these days for myself....
> I am usually wrangling
> pixels all day. heh.
>
> Good luck on your quest Christopher. The
> Daguerreotype hasn't even begun to be
> explored for new possibilities.
>
> Christopher Lovenguth wrote:
>
> > I've been trying to think of a way to seal a
> daguerreotype plate with some
> > sort of substance so that I don't have to have it
> under glass. Can anyone
> > think of a way to do this? I don't want it to
> alter the finish so it would
> > have to be some sort of material/chemical that can
> be applied without
> > severely affecting the finish. It will have to be
> neutral as well in order
> > not to tarnish the silver. Third it would have to
> be able to be applied
> > carefully because the slightest touch destroys the
> image. So I'm thinking a
> > sort of liquid that I can either dip the plate in
> or spray the plate with.
> >
> > I couldn't come up with any ideas that I'm just
> willing to try. It's not
> > that I want to be able to put my paws all over the
> image and then be able to
> > use window cleaner to wipe them off. But I like
> the quality of just the
> > plate without glass. The problem is showing it to
> someone who might not
> > understand that just the slightest touch will ruin
> it. Plus transportation,
> > my own viewing (I'm very clumsy) dust, etc. Right
> now I have been using
> > neutral plastic film holders sheets. But even with
> those if you take the
> > plate out of them a couple of times start to
> scratch the image because of
> > dust particles. Just keeping the plate in the
> sleeve and looking through it
> > you lose subtle qualities.
> >
> > This is not as much of an issue with some of my
> gilded plates. For some
> > reason some of them have become almost touchable.
> The thing is I'm sort of
> > select gilding my plates now since a long time in
> the gold tends to darken
> > my plates too much. I'm now taking my plates out a
> bit faster then I used to
> > because I like the quality and effect, but these
> images are more fragile and
> > can be wiped off with the slightest touch just
> like the plates that haven't
> > been gilded.
> >
> > I'm willing to experiment with a bad plate so
> suggestions are appreciated.
> > -Chris
> >
> >
>
_________________________________________________________________
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> http://messenger.msn.com
>
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