Re: Modifying bleaches

From: MARTINM <martinm@SoftHome.net>
Subject: Re: Modifying bleaches
Date: Tue, 30 Nov 2004 10:20:37 +0100

> It may depend on the specific stabilizer - since conversion to
> silver iodide can be carried out routinely on commercial ultra-fine
> grain (and supposedly stabilized) silver bromide emulsions.

I thought we were talking about printing paper
emulsions. Chlorobromide emulsions usually use much more powerful
stabilizer than iodobromide emulsions, especially in neutral to cold
tone papers. I used 1-phenyl-5-mercaptotetrazole at 0.18 mmol/mole AgX
in chloride emulsion and this halted ripening. And I can't seem to
wash this stuff off once it's mixed in (as far as I know, fixing the
emulsion is about the only practical way to get this stuff off the
emulsion, but that's not useful anyway). This stabilizer reduces too
much speed in bromide emulsions so I don't use it in them.

How do you measure the degree of conversion? What kind of time does it
take for the conversion to take place?

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