[pure-silver] Re: You're making your own emulsion!
- From: Ryuji Suzuki <rs@xxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Fri, 31 Dec 2004 18:03:59 -0500 (EST)
From: "Gene Johnson" <genej2@xxxxxxx>
Subject: [pure-silver] Re: You're making your own emulsion!
Date: Fri, 31 Dec 2004 13:52:30 -0800
> This stuff needs protecting. I've been looking for info on edwardian
> era portrait studio processes and have actually found very little.
> I'm starting to understand that much knowledge simply gets lost in
> time.
Don't worry, the art of emulsion making has never been described in
full details. Old books like Wall and Baker contain numerous annoying
misconceptions, or maybe tricks that worked then but not in my hand.
FIAT and BIOS were valuable addition to some books published in
1960's, which are good in describing basic principles but not detailed
enough. Then there are lots of patents but it also takes time and
effort to weed out which inventions were "real" and relevant to what I
want to achieve. Academic researches revealed more and more about
emulsion chemistry. What I needed to do is to combine ad hoc or
empirical knowledge of patents with more systematic, generalizable
theory of science, because it's impossible to control great many
variables involved. Still, there are a lot of guesswork.
> If all else fails, you can now ensure that future generations have
> something to print on! Do you have any thoughts about producing
> your paper in any quantity ever?
Well, Rochester and Ashigara (where Fuji plant is) are alive. Chinese
Lucky is also a Kodak subsidiary. Forte is back in operation. So there
is no room for me to commercialize my hobby. The best I can do is to
put together a booklet where everything is described, so that anyone
can try.
With a bit of investment in lab apparatuses and stocking up quality
gelatin, it's possible to make a chlorobromide emulsion in less than
an hour. Then you coat it by hand and dry in a light tight cabinet. I
go out for lunch, dinner, tea break or whatever. Come back and
print. When the supply is out, it's all over for the day, and prepare
a few more sheets of paper with sizing solution for the next
session. This way, you can make several test strips and a couple of
11x15 prints a day.
I already spent a lot of silver nitrate for experimenting with
different formulae, but with a successful formula, 10g of silver
nitrate would coat about 3 square meters of paper. This is some
200-300 ml of emulsion. It's possible to upscale this to a couple of
liters, but there are zillion difficulties in upscaling further. For
example, Toyo Kanpan (Eastern Dry Plate Company) had good dry plate
emulsions. Dainippon Celluloids (Japan Celluloids) made an emulsion
lab to test possibility of commercializing photographic films. They
were relatively successful when they decided to make a big factory for
new Fuji Photo Film. But they experienced huge degree of difficulties
in upsizing their plants from small labs to a large plant.
Plus, I'm talking about very primitive setup here. Today's commercial
emulsions are made in more complicated precipitation apparatuses with
main mixers, a premixing chamber with a premixer, various measurement
probes and a computer controlled feedback control system.
So, in short, my emulsion hobby is a fundamentally different thing
than today's commercial products. It's more of a 19th century
technology where important bits of 20th century discoveries are
backported. However, it has its own fresh look to it, and it will be a
great addition to have in the time of inkjet printing. In this sense,
it is same as classic non-silver processes. But what's great about
silver gelatin process is that I can print from my roll film with my
enlarger.
--
Ryuji Suzuki
"Keep a good head and always carry a light camera."
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