View Full Version : hardening vs non-hardening fixers (for film)

31-Oct-2011, 12:39
When I started developing B&W film 2+ years ago I bought some D-76 and "Kodak fixer" and have been using that since. Now that I'm exploring the idea of changing developers, I've been looking at fixers as well. So now I have to think about rapid fixers and hardening or non-hardening fixers. I think I know what "rapid" means. Hardening I'm not so sure about. Anyone care to give a quick discourse/pro-con discussion?


Gem Singer
31-Oct-2011, 13:11
Kodak Fixer (hypo) is sodium thiosulfate.

Rapid fixers, such as Kodak Rapid Fixer, Ilford Hypam, Formulary TF-5, etc, are ammonium thiosulfate.

Rapid fixers are not necessarily hardening fixers. The hardener (acid) is optional. Not recommended for Ilford films and papers.

According to S.Anchell and B.Troop in "The Film Developing Cookbook", since today's films may contain silver iodide, as well as silver chloride and silver bromide. it's best to use a rapid fixer.

Lynn Jones
31-Oct-2011, 13:15
I strongly recommend NO hardening fixers.


31-Oct-2011, 16:01
Do not Adox films need hardener fixers?

31-Oct-2011, 16:14
Do not Adox films need hardener fixers?

I've seen that a hardener is often recommended, typically in the fixer, occasionally in the stop....because the emulsion is 'supposed' to be softer...

But, I don't do either and have never had a problem - though I've only used Adox Pan 25....and it doesn't 'appear' to be any softer than FP4+ IMO

Louie Powell
31-Oct-2011, 17:32
Hardeners have a significant downside - they make it much harder to achieve an archival wash.

Many years ago, film emulsions were much softer and required hardening and an hour or more of washing in running water. Modern films don't have that problem, so hardening fixers aren't really required. You can use standard rapid fixer, some kind of fixer removers, and still get an archival wash by simply soaking the film in a succession of fresh-water baths - typically, five or six soaks of a couple of minutes each should be enough..

The film that has a reputation for a soft emulsion today is Efka - but if you are reasonably careful in handling it, you still don't need to use a hardening fixer. Clip your fingernails!

The paper that was most notorious for having a soft emulsion was Agfa Portriga Rapid. It was a beautiful emulsion, but it is no longer available (both because the manufacturer went out of business, and also because its manufacturing process involved chromium that presented environmental problems). You never want to use a hardener with modern fiber based papers. FB paper is hard enough to wash, and using a hardener only complicates the process. Resin coated paper is much easier to wash, and the emulsion is also tougher.

As far as sodium thiosulfate versus ammonium thiosulfate - in my book, there is simply no debate. Sodium thiosulfate comes as a powder, and is a PITA to mix, and it takes much longer to clear. Ammonium thiosulfate comes as a liquid concentrate and is very easy to mix, and works much faster. So I use rapid fixer.

Roger Cole
31-Oct-2011, 18:03
If you use Kodak Rapid Fix you can include or leave out the hardener as you please. It's the part B small bottle (and is mainly or completely sulfuric acid - don't get it on your clothes.) Other rapid fixers just don't include it.

Everyone says it's not needed with modern films, as above. It does make it slower to wash, but I've continued using it for film (and washing longer) because I'm a bit paranoid about scratches (which I never get, either from hardener, careful handling or both) but don't use it for paper at all. With the Kodak you can mix both from the same batch. You can also add it for Efke if you find you need it and not for other films.

You can get non-rapid fixers that are in liquid form and easy to mix, such as Kodafix. In the old days I used that for paper. It's a hardening fixer though. The only advantage is that, for paper, rapid fixer seems to exhaust more quickly - this from memory. Now fixer is cheap enough I don't really care.

Bottom line is, get any modern rapid fix and mix to instructions for film strength if there's a difference (you can leave the hardener out of the Kodak if you prefer) and you're set. Some like Kodak will specify a weaker paper strength. Some of that depends on your fix time and wash times, but wash times can be substantially reduced for FB papers by fixing for brief times (1 minute at most) in film strength rapid fixers. RC paper it doesn't much matter as they wash so quickly anyway.

31-Oct-2011, 18:10
Thanks for all the replies, folks.

J. E. Brown
1-Nov-2011, 06:27
[QUOTE=Roger Cole;798125]If you use Kodak Rapid Fix you can include or leave out the hardener as you please. It's the part B small bottle (and is mainly or completely sulfuric acid - don't get it on your clothes.) Other rapid fixers just don't include it./QUOTE]

I use Kodak Rapid Fix too, and everytime I mix a batch tell myself to leave out the hardener. I have thought that there may be something else, chemically, that the hardener offers and my negatives would be ruined. If anything, without the hardener, it appears that the fixer will be more 'efficient'.

Aside from softer emulsion, and allowing the fixer to work without interference of a hardener, are there any other changes to the fixer without part B?

Thanks for the responses, and thanks for asking the question, Gregg.

Kind regards,


1-Nov-2011, 07:30
Do not Adox films need hardener fixers?

I've been using Adox films for a few years now developing in a pyro (actually Pyrocat-HD) and fixing in Ilford Hypam. I see no issues at all but that is because of the use of Pyrocat-HD.

John Jarosz
1-Nov-2011, 10:27
I have been told (but I have no source to cite) that the gelatin in all the emulsions will harden over time with or without a hardener.


1-Nov-2011, 14:22
I'm hijacking this thread:

Other than time or smell do you all notice a difference when using different fixers?

I've never considered using anything different than what has been offered in the darkrooms. And I can't remember any instructor ever talking about the merits of 1 fix over another.

Just curious