Re: Increasing Carbon speed.

From: Bill William <iodideshi@yahoo.co.jp>
Subject: Re: Increasing Carbon speed.
Date: Wed, 15 Dec 2004 19:20:29 +0900 (JST)

> > > How much of an increase are you seeing?
> >
> > About 2 stops.
>
> That is incredible.
> (but just under the roof...)

Not really. I get that much increase in speed in chlorobromide
emulsions with a different dopant.

> You did not report your starting speed.

If you are just looking at the magnitude of speed increase, that is
irrelevant. I've seen the effects in both slow and fast emulsions.

> Is this in addition to or instead of
> other sensitization?

These are in conjunction with chemical sensitization, which remain the
same. Stabilizers are the same. Only presence of dopants is modified.

> Are other properties unaffected?

Nothing adverse. With chloride emulsion the other dopant seems to
increase contrast, so I have *unwashed* chloride paper made with single
jet that is just as fast and contrasty as commercial papers.

> Why on earth was your attention drawn to cerium?

Because it's on the earth, and it's described in literature.

> What happens when it doesn't work?

You'll get no speed increase or some loss. Loss may be because the
crystals are said to be smaller with the doped version. Iodide
content seems to affect the effect of doping as well but the paper did
not describe that part at all and I only tried a couple of points so
don't know much.

Now you have to describe your emulsions.

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