From: ken watson (watsok@frii.com)
Date: 01/03/02-09:51:31 PM Z
Charles,
I am writing off list to thank you for the detailed input. I do have a few
questions, if you feel up to answering them.
What do you sub glass with?
Is "photographic gelatin" not the pure stuff that needs everything added
back in for sensitivity?
Is the bloom rating important?
As for coating. I was thinking of following Eastman. He had a roller in a
trough. I was planning on "rolling" the glass over the roller that is in
contact with he gelatin emulsion in the trough. If the glass is relatively
warm I was hoping that it would level itself out before setting. Any input?
As for books. If you would feel comfortable to loan one of them to me for
copying it would be appreciated. If a deposit to insure it's return would
make you more comfortable I would understand. On the other hand if you
could get around to copy a book I would be happy to reimburse you.
I do wet plate photography so I understand that not all things are possible
to include even in the best effort to describe a process. My interest is
to get a "good" emulsion, what ever the speed may be. ASA 25 seemed a
reasonable target from a naive point of view. My understanding was that
Gelatin emulsions, any emulsion, would be faster than collodion. I shoot my
collodion images at f11 / 16 for three seconds. I believe this is a ASA
rating or 1/3 or 1/6?
My first goal was to only make orthochromatic , sorta, type of film. It
seemed that the addition of only one common dye would do this. Ethyl Red is
what I was planning on using. Seems easy to find and relatively low cost.
So could you pass along what equipment you are using to make your emulsion?
With the trouble I am having find a central source for this I think it
warrants setting up a web page for all the information that folks like you
are generously passing along.
As for the book scalpers. It seems they are interested is selling a
book....any book that might be old and will bring them some money. They have
no use for the information that is in them. We ,on the other hand, do not
really need the book itself but the info they contain. Hopefully in the
future we can separate the two.
..-----Original Message-----
..From: Charles Steinmetz [mailto:csteinmetz@netexpressway.com]
..Sent: Thursday, January 03, 2002 8:04 PM
..To: alt-photo-process-l@usask.ca
..Subject: Re: emulsion formulas
..
..
..I've made and coated plates for many years. It's not particularly easy if
..you want results
..equal to commercial negative materials, although it's not too hard to make
..plates that give
..recognizeable images.
..
..ISO 125 is a very challenging target, as is panchromatism (or even
..orthochromatism).
..Blue-sensitive emulsions of ISO 5-10 are hard enough for the
..beginner. You
..*will* need to
..sub the plates. You will also work VERY hard to get even coatings that
..aren't full of dust
..and debris. I strongly suggest looking at Jim Browning's coating machine
..plans to see how
..it's done right.
..
..There are so many variables (especially the gelatin) that it's almost
..pointless to give
..specific recipes. Any recipe will take much tinkering before you
..get it to
..work very much
..like it worked for the person who gave it to you. My first copy of Baker
..was passed down
..to me by a Kodak emulsion scientist, and is full of exquisitely detailed
..notes. Even so, my
..results were very different from his. Until quite recently,
..emulsions were
..tuned by mixing
..various lots of gelatin to get the desired speed with a tolerable
..fog level
..(both are strongly
..influenced by minute traces of things -- some known, some not -- in the
..various gelatins).
..Lately, the commercial operators use neutralized gelatin and add the trace
..impurities
..themselves.
..
..Here is a brief bibliography from my bookshelf (this is an update
..of a list
..I posted some
..time ago):
..
..Photographic Emulsion Technique, by T. Thorne Baker
.. 2nd ed. 1948 American Photographic Pub. Co. Boston [1st ed. 1941]
.. This is the single most useful book I've seen, as far as practical
.. emulsion-making is concerned. That said, please do not give the
.. internet photo-book pirate/pimps the >$100 they are asking.
..
..Photographic Emulsions, by E.J. Wall
.. 1929 American Photographic Pub. Co. Boston
.. The second most useful book. Same comment about pricing.
..
..Photographic Chemistry, vol. 1, by Pierre Glafkides
.. 1958 Fountain Press London
.. Part II is an excellent general discussion with recipes.
..
..The Photographic Emulsion, by B.H. Carroll, D. Hubbard, & C.M. Kretschman
.. n.d. Focal Press London & NY
.. A collection of seminal papers from the late '20s and early '30s. No
.. instructions for making emulsions, but lots to help you understand and
.. improve your methods once you are over the beginner's hump.
..
..The Theory of the Photographic Process
.. 1st ed. 1942 Macmillan Co. NY C.E. Kenneth Mees, ed.
.. 2nd ed. 1954 Macmillan Co. NY C.E. Kenneth Mees, ed.
.. 3rd ed. 1966 Macmillan Co. NY C.E. Kenneth Mees & T.H. James, eds.
.. Very technical compendium of all things silver-gelatin. Again, no
.. recipes for the beginner, but most all the public-domain information
.. on silver in one place. In the 1st ed., an excellent discussion of
.. spectral sensitizing occupies Section VI. It's much attenuated in
.. the later editions.
..
..C.B. Neblette has a very basic, but good, overview chapter in the
.. various editions of Photography: Its Materials and Processes (and its
.. succesor, Neblette's Handbook of Photography and Reprography), and in
.. Photography: Principles and Practices
..
..Photographic Materials and Processes, by Stroebel/Compton/Current/Zakia
.. 1986 Focal Press Boston & London
.. A fairly detailed overview chapter. No recipes.
..
..Kodak published a pamphlet with a recipe for slow in-camera film, called
.. Making a Photographic Emulsion, publication AJ-12 (long out of print,
.. but sometimes available by calling Kodak's 800 number -- it depends on
.. the representative you get). Makes a fractional-ISO emulsion.
.. [I have a set of scans I can send if folks just can't find it]
..
.. [I also have scans of 8 pages from another old book, whose
..title is lost
.. in the mists of time]
..
..Aristotypes and How to Make Them, by Walter E. Woodbury
.. 1893 Scovill & Adams NY
.. Paper emulsion recipes, both gelatin and collodion.
..
..Jim Browning has posted his recipes and methods for making dye-transfer
.. matrix film, from which you can learn a great deal.
..
..
..Best regards,
..
..Charles (sorry for the spam below)
..
..
..
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