[pure-silver] Re: Adding Pot Bromife to PC-TEA
- From: Ryuji Suzuki <rs@xxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Fri, 07 Jan 2005 17:07:22 -0500 (EST)
From: "Koch, Gerald" <gkoch02@xxxxxxxxxx>
Subject: [pure-silver] Re: Adding Pot Bromife to PC-TEA
Date: Fri, 7 Jan 2005 15:51:38 -0500
> A few weeks ago Gainer changed the formula in an APUG post by
> reducing the amount of Phenidone to 0.225 g.
I don't know what that small change offers. Activity of phenidone type
developer changes slower than a linear relation when the concentration
is changed.
> This helped a bit with
> the contrast/density problem. Soon after that someone suggested
> adding 0.25 g of potassium bromide to the concentrate. This really
> cleaned up the negatives and greatly improved the contrast/density
> problem.
There are some published data that compared the effect of a bunch of
antifoggants in terms of suppression of developer fog and absence of
suppression on weakly exposed grains. Bromide isn't the best on this
one, and you can easily avoid the problems you're having by using
1-phenyl-5-mercaptotetrazole. You should get a gram or two, which is
enough to make a few hundred liters of developers.
--
Ryuji Suzuki
"Keep a good head and always carry a light camera."
=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you subscribed,)
and unsubscribe from there.
Other related posts:
