Re: Modifying bleaches

From: MARTINM <martinm@SoftHome.net>
Subject: Re: Modifying bleaches
Date: Mon, 29 Nov 2004 18:46:25 +0100

> You probably know you can convert any silver chloride emulsion into
> a silver bromide or silver iodide emulsion by simply bathing the
> silver chloride emulsion in a potassium bromide or potassium iodide
> solution. A silver bromide emulsion can be converted into a silver
> iodide solution by using a potassium iodide solution.

Since you brought this up outside the context of silver gelatin
emulsion making, I thought to point out that this doesn't work in
finished emulsions. More specifically, this halide conversion does not
work once stabilizing agents that work as a ripening retarder is
added. Before adding stabilizer, it works. I routinely make
chlorobromide emulsions this way - make 100% AgCl first and then
convert certain mole fraction into AgBr. Then ripen, digest and
stabilize.

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