From: ken watson (watsok@frii.com)
Date: 01/02/02-09:58:34 AM Z
Thanks for the replies. I have run across Holographic folks playing with
emulsion but it was more along the lines of adjusting the sensitivity and
development discussions around specific products. So if you find the
specific article info on making emulsion I would be interested. I will also
go visit a local university. I had come to an end and you guys have given
me a few more trail's to follow, thanks.
As for subbing a plate before coating. Albumen seems to still be a good idea
but I also have read about using India rubber in Benzene or...can not
remember the other solvent. This could just mean thinned rubber cement that
is at a typical art supply house
As for coating , I had planned to "roll" it on as did Eastman in his
original process.
As for dyes, I am only trying to make Orthochromatic emulsion. At the moment
the Red insensitivity is a plus, so from what I have been able to read Ethyl
Red dye will do this. It is available at relatively low cost for staining
microscope slides. About $25 for 100 grams I believe . I looked into the
other dyes for sensitizing lippman type of plates ( curiosity ) and it was
in the neighborhood of $100 for the smallest amount of pure dye that I could
find. As for direct sales issue to individuals, contact me off list and
maybe I can help some:
watsok@frii.com
..-----Original Message-----
..From: Tox Gunn [mailto:tox@remarque.org]
..Sent: Tuesday, January 01, 2002 7:21 PM
..To: alt-photo-process-l@skyway.usask.ca
..Subject: Re: making Gelatin Emulsion
..
..
..The SPIE conference proceedings from the Holographic Materials
..and related
..conferences of the late 90's have information on this - browse the stacks
..at your local college library. Based on their articles, I've been slowly
..getting the materials together. (This is incidentally also a pretty good
..place to start looking for Lippmann photography information -
..some of Hans
..Bjelkhagen's articles are excellent overviews.) Seems that university
..students have been doing more work in homebrewed plates in the
..last several
..years since the commercial holography offerings from Agfa narrowed. The
..best article on emulsion synthesis I've found was by some
..students in Japan
..in 1998 or so, who did tests of a dozen different sensitizers and a dozen
..differing concentration/ripening schedules - when I find the paper again
..(my apartment is currently a pit), I can post the cite if you would like.
..
..Some things to keep in mind:
..
..I've not found a good source for the sensitizing dyes - minimum
..quantity is
..usually off-scale and the issue of direct sales to individuals has gotten
..no easier since 9/11. Example - for one of the cyanine series dyes I was
..looking at, for a batch of a couple dozen plates I would have needed ~2ml
..of a 1:1000 w/v sol'n in ethanol but the dye was sold in units of 1 gram
..powdered for ~$120, and only if I were associated with a manufacturer or
..university.
..
..Glass plates may need be subbed before coating with the emulsion.
..
..The impression I get from the lit is that the coating method and
..consistency may have a lot of personal variability. Some
..decisions to make
..include: spin coating vs. spreading with a meyer rod, coating
..platewise vs.
..coating a large sheet and cutting it down, etc.
..
..If you get there before I do, please share your notes and
..observations!..;)
..
..Good luck,
..Tox
..
..
..At 06:27 PM 1/1/2002 -0700, you wrote:
..>Does anyone on this list know where to find recipes for making gelatin
..>emulsion?
..>
..>I am not looking for liquid light which seems slow from today's point of
..>view, maybe it is mostly silver chloride? I am looking to make
..a relatively
..>modern silver bromide/iodide asa 25 to 125 B&W emulsion to coat glass
..>plates.
..>
..>The more in depth of how to actually process, digest , sensitize
..the better.
..>
..>.
..
..
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