Discover mag article

[Tom B.]

2 parts - a profile of a modern Daguerrotypist and a piece on Yves Gentet and his Ultimate emulsion.

http://www.discover.com/feb_02/featphoto.html

[Tom B.]

Some interesting images and tech info here:
http://www.newdags.com/index.html
I'm interested because I think the technique might eventually be adaptable to holography. The Bequerel process looks interesting. I don't know why they go on and on about various silver on copper plating processes when silver is so damned cheap. I picked up a chunk of pure silver ($10 oz. CDN, probably $6/oz. US) at a local coin shop and some iodine at the druggist. Now all I need is a plate forming and polishing machine and some very patient nudes

[Martin]

Resolution is ok for holography. However, I would expect the recording layer (the "emulsion") to be too thin to record any volume effects. Actually, there is a patent dealing with "Master hologram and micropattern replication method" - US 5059499.
Alt.photo might be a good address since several people there are involved with dag making. Have a look at:
http://duke.usask.ca/~holtsg/photo/current/subject.htm

[Colin Kaminski]

I have never heard of this process. Can someone provide me with a brief overview of what the final product is? Is this a 3-D image? Or a enhanced color image? I looked for some information on Tom's link but I only found images and processes not basic information.

Thank You...

[Martin]

"I have never heard of this process. Can someone provide me with a brief overview of what the final product is? Is this a 3-D image? Or a enhanced color image? I looked for some information on Tom's link but I only found images and processes not basic information."

Colin, daguerreotypes are at the very beginning of photography. They resulted from the collaboration of Niépce with Daguerre. If you read French, http://www.gallica.bnf.fr has a paper by Daguerre to download.
Daguerreotypes are not 3-D. They are black and white and have a "metallic" look.

As to adapting daguerrotypes to holography, the most severe drawback is their lack of speed. Since the silver halides are not formed within a protective colloid ("emulsion") but on a silvered copper plate, speed is very low.

[Tom B.]

The Daguerre society http://www.daguerre.org has a good deal of historic info in their resource section. As for holography applications, the patent mentioned by Martin is the only one I know of so far. The attraction is that it is an essentially grainless medium like DCG. The drawbacks are many: 2D only (no reflection holos), extreme slowness, sensitivity only to blue/UV, very tricky plate preparation, nasty mercury development (though the Bequerel process might work) and on and on. Maybe some of these could be overcome if the technique was reinvented with more modern chemistry? It would be interesting to try a Daguerre contact copy of a transmission hologram illuminated with incoherent UV. If it worked, the result would be a shiny rainbow holo that might be very pretty.

[John Hurlock]

I've made Daguerreotypes for almost 50 years.
Maximum speed of Daguerreptypes is ISO 0.05 to 0.10.
I'd like to make holograms on Dags plates.
Anyone interested?
More info on Dags can be found at;

http://www.daguerre.org or http://www.newdags.com

[Tom B.]

Yes I'd be interested in your results. As mentioned in my previous post below, I imagine the easiest process would be to make an incoherent UV contact copy of an (unbleached) transmission hologram - I think you would get something like an embossed hologram (those shiny metallic holographic stickers you see everywhere). This would be FAR less difficult and expensive than direct recording with a sufficiently powerful short wavelength laser.

Colin has some experience with mastering embossed holos and might have some tips on technique and best subject matter. If you don't have facilities for making a master holo, I'm sure that someone on the forum would be willing to make one for you, perhaps in exchange for a finished holodaguerreotype? Alas my setup at present is not much good for transmission holos, or I would volunteer.

[Dinesh]

I've heard of this process but I didn't think anyone had done this since the nineteenth century. However, reading all of this, I think it'd be interesting for holography. The reason I say this is that the thickness is quoted as 0.0005 in, which translates to about 12 microns, in silver. In standard embossed holography the photoresist layer is usually only about a micron or so and is exposed so that the amplitude of the fringes is less, ie you don't go all the way down to the glass. The Resist hologram is sprayed with silver ("The Silver Mother") and dunked into a tank for electroplating, which coats the Silver Mother with a thin Nickel layer ("The Nickel Master"). This is then peeled off the Silver Mother. The problem I've heard is that if the amplitude of the recorded fringes is too high (>~ 1 micron) then the Nickel Master does not peel cleanly.

The efficency of a Raman Nath diffraction is dependant on the fringe amplitude. Also, according to papers by Maharam and Gaylord and others, poalrisation effects begin to appear when the fringe amplitude-to-spacing is about 3:1, in other words fringes 1 micron high spaced out at 300 nm would show efficencies dependant on the polarisation of the reconstruction beam. If this dag type process could be adapted to embossed holography, you'd have a material capable of taking fringes 12 microns high and should therefore be extremely bright and capable of polarisation effects with high extinction ratios. While it's possible to make DCG 12 microns deep, there's no way of creating a pure surface grating, while here it seems to be a pure surface grating with no Bragg components. Diffraction seems to be pure Raman Nath.

A further advantage is that you don't need to create a Silver Mother, it's already a Silver Mother! The peeling problem might still occur, since the silver still needs to be converted to Nickel for creating shims. I believe Silver is too soft. I wonder, however, if it may not be possible to mix something in with the Silver in the Daguerrotype itself to strengthen the Silver so that the Silver would still be there for photosensitization but would be gain mechanical strength by adding a photographically inert metal.

The sensitivities quoted seem to be for incoherent light. I wonder how the ISO figures quoted by John Hurlock translates to spatial frequency response in coherent light? It would be interesting to know an ISO figure for, PFG-03 for comparison. Jeff? Martin? Sergio?

[Martin]

"This would be FAR less difficult and expensive than direct recording with a sufficiently powerful short wavelength laser."
...which makes me wonder if a "dag layer" could be spectrally sensitized. At first glance, I would assume so.