Search found 8 matches

by Bill Troop
Wed Aug 07, 2019 3:03 am
Forum: Black & White Film Development
Topic: Dichroic fog
Replies: 2
Views: 5273

Re: Dichroic fog

This kind of dichroic fog occurs when developing in the presence of a strong silver solvent, for example, a fixer. Because of the way our typical use of developers and fixers has changed over the years, this is no longer a problem in most scenarios. In order to achieve dichroic fog because of not us...
by Bill Troop
Thu Nov 09, 2017 7:20 am
Forum: Black & White Film Development
Topic: Fx-55???
Replies: 6
Views: 7909

Re: Fx-55???

There are two known developers which Crawley formulated with ascorbate. One is FX-50, a proprietary formula, and the other is FX-55, a public formula. It's easy to confuse them. I will be able to print FX-50 with permission in the upcoming Film Developing Cookbook, which should be available sometime...
by Bill Troop
Wed Aug 09, 2017 2:37 pm
Forum: Fixers
Topic: Convert TF-2 to a rapid fix with the addition of ammonium chloride
Replies: 3
Views: 6504

Re: Convert TF-2 to a rapid fix with the addition of ammonium chloride

These are interesting questions and will be dealt with in Film Developing Cookbook 2. Certainly, you can, and one might say should, add ammonium chloride to TF-2, but I would then worry that the pH would be high enough to cause ammonia fumes to emit. Therefore, I would suggest omitting the Kodalk. T...
by Bill Troop
Mon Dec 05, 2016 3:16 pm
Forum: Fixers
Topic: Alkaline Hypo
Replies: 12
Views: 12981

Alkaline Hypo

I would be cautious about the scaling up you're contemplating. As far as I know, concentrating sodium thiosulfate has never been attempted or recommended in the entire photographic literature. When you're trying to do something like that, there is usually some gotcha. The only very slight scaling up...
by Bill Troop
Sun Dec 04, 2016 3:44 pm
Forum: Fixers
Topic: Alkaline Hypo
Replies: 12
Views: 12981

Alkaline Hypo

Hi Andy, you raise a number of issues. First of all, if an alkaline fixer is going to be used with open trays for prints or sheet films, then it is desirable to control the pH close to neutral to avoid evolving ammonia. So I'd say your main mistake was thinking you had to have a high pH. You can, bu...
by Bill Troop
Thu Mar 10, 2016 4:33 pm
Forum: Black & White Film Development
Topic: Alkaline fixer?
Replies: 10
Views: 11655

Alkaline fixer?

I want to make clear that FDC couldn't exist in any form without Steve. I will be seeking his advice on a number of issues for the 2nd edition.
by Bill Troop
Thu Mar 10, 2016 7:27 am
Forum: Black & White Film Development
Topic: Alkaline fixer?
Replies: 10
Views: 11655

Alkaline fixer?

My memory is that Gordon showed that the more alkaline (or less acid) the fixer, the greater the stain. I would say, if you're getting the degree of stain you want with an acid fixer, fine, but if you want more stain, which I think is a good thing, then you would probably move to a neutral-to-alkali...
by Bill Troop
Wed Mar 09, 2016 2:59 pm
Forum: Black & White Film Development
Topic: Alkaline fixer?
Replies: 10
Views: 11655

Alkaline fixer?

That's an interesting question. The problem with altering a commercial formula is that you can't know exactly what's in it. Suppose it has a hardener: if it's an aldehyde, it could polymerize if you alkalinize the product. If it's an alum hardener, it will sludge out. But if there is no hardener and...