Re: a versatile surfactant that kills bubbles

From: Etienne Garbaux <photographeur@softhome.net>
Subject: Re: a versatile surfactant that kills bubbles
Date: Sun, 16 Jan 2005 19:04:58 -0500

> After using some of the commercial papers of today, I'd kill for the
> commercial papers of 20 years ago! (Well, as long as we're at it, make
> that 20 to 30 years ago....)

Well, I meant something negative but you never know who takes it
positively. The particular bromide emulsion I had in mind is a bit
unusual compared to current commercial emulsions, because it is a
bromide paper, and it gives neutral black hue when developed in
standard print developer (DS-14), but it tones exceptionally
well. When I stick a test strip to polysulfide toner, I get immediate
hue change and the hue is orange brown, unless I dilute the toner very
much. How does it work with gold or other toners? I don't know.

I don't have an SEM setup so I can't see the grains, but I bet this is
very fine grained. The precipitation condition favors extremely fine
grain. Indeed, an emulsion expert in Rochester was quite skeptical if
I would get a useful emulsion out of it. But thanks to cerium doping
and sulfur sensitization, I can get contrast grade 4 at speed around
ISO P100 and softer contrasts. When I made softer grades, speed was a
bit too high to my taste. But they don't seem to fog in my Thomas
safelight wide open (of course, this is a bromide paper).

> Is there any other way? ;-) I've actually never tried any of the
> commercially-available liquid emulsions.

Neither did I. I've seen works made with several types of those
products, as well as detailed comments printed in Reed and Jones, as
well as other info from users I exchange info with. They say unless
they bleach the print, the prints don't respond to toners well, so I
think most of those products have larger grains than mine.

> For years, I lived next door to the senior emulsion chemist for a
> major photo manufacturer -- he and his colleagues helped my home
> emulsion experiments along with extremely valuable advice and
> support.

That smells like AGFA-Gevaert...

My emulsion making setup is pretty simple. If you have a magnetic
stirrer with a hot plate, reacting vessel, thermometer, and regular
lab supply and chemicals, that's pretty much all that's needed. I
don't even have a silver electrode to measure pAg (vAg) so my setup is
pretty low tech and pAg profiles and everything are limited to those
where calculated values are believed to be close to actual values.

Should I try to send a manuscript with a formula (Part 1 through 6,
with so many ingredients) to Photo Techniques and see how many new
editors will I see before they call me?

--
Ryuji Suzuki
"People seldom do what they believe in.  They do what is convenient,
then repent." (Bob Dylan, Brownsville Girl, 1986)