Film Fixer Types & Hardeners

[SPS731]

I have some questions about film fixers. I have always used Kodak Rapid Fix when processing my film. Now I'm looking at Ilford Fixers and I see they have two different fixers. One is based on ammonium thiosulphate, and the other is based on sodium thiosulphate (hypo). Is there any difference in these two chemicals when used as fixers? Specifically: permanence, image characteristics, and hardness.

Kodak's Rapid Fixer contains hardner and the Ilford fixers do not. Do most people add hardener to the Ilford products or just use the fixers as formulated?

Thanks in advance for your replies.

 

[Ian Grant]

Ilfords Hypam is a great Fixer, I've been using it since about the 1970's, you don't need to use a hardener.

Modern films are all pre-hardened and robust, well all except EFKE films.

Ilford only list 2 fixers now Hypam & Rapid fix, apart from the machine process fixer and they are all ammonium thiosulphate based.

So just use as is without a hardner.

Ian

 

[Photo Engineer]

There is no real difference between the two types of fixers except for speed of fixing and capacity. Ammonium based fixers are generally faster in fixing film and paper and they have a small edge in capacity if the concentration of the fixing solutions are the same.

PE

 

[SPS731]

Ian, you are right they are both ammonium thiosulphate based. I misread the data sheet. I believe the Kodak Rapid Fixer is ammonium thiosulphate based also.

I wonder why Ilford offers two fixers for manual processing that are so much alike? Oh well, the only thing that matters is that I have clear negatives with good permanence, and enough hardness so they are not easily damaged.

 

[Brian Bullen]

PE, is one fixer more acidic than the other? I've been experimenting with caffenol and am a little worried about sodium carbonate and acidity in the fixer. I've read that acidic fixer or stop for that matter can cause pinholes with the use of carbonate.

 

[Photo Engineer]

PE, is one fixer more acidic than the other? I've been experimenting with caffenol and am a little worried about sodium carbonate and acidity in the fixer. I've read that acidic fixer or stop for that matter can cause pinholes with the use of carbonate.

Any hypo based fixer can be either acidic or basic. On the acid side, fixers cannot go below about 4.5 due to decomposition of the thiosulfate. On the basic side, fixers with ammonium ion cannot go higher than about 9.

Acidic fixers use alum for hardening and alkaline fixers, if hardened, use an aldehyde such as formalin.

Test we ran showed that no acid fixer caused pinholes with a carbonate based developer. Thus, we changed all color developers for color papers from Kodalk to Carbonate and used a 2% stop bath before the blix with no problem. The same is true of C41 films, and this is all at 100 F.

No, I can say that properly hardened film (hardened in the factory) will not give pinholes from carbon dioxide release from post development acid baths. Pinholes are usually found if you don't prewet, don't properly agitate, or use a very very soft film or a high temperature with B&W.

PE

 

[radiantdarkroom]

I don't know why but I found the The Kodak rapid fixer always lasted longer with the Hardener added for film processing. Does it really matter if the film is even harder after fixing if it's a pre-hardened film anyhow?

 

[Photo Engineer]

Maybe more of the complexed silver is washing out in the wash water rather than into the fix. IDK. I never studied this. It may also be an artifact. Did you test the fixer and film or paper with test solutions?

PE

 

[SPS731]

Any hypo based fixer can be either acidic or basic. On the acid side, fixers cannot go below about 4.5 due to decomposition of the thiosulfate. On the basic side, fixers with ammonium ion cannot go higher than about 9.

Acidic fixers use alum for hardening and alkaline fixers, if hardened, use an aldehyde such as formalin.

Test we ran showed that no acid fixer caused pinholes with a carbonate based developer. Thus, we changed all color developers for color papers from Kodalk to Carbonate and used a 2% stop bath before the blix with no problem. The same is true of C41 films, and this is all at 100 F.

No, I can say that properly hardened film (hardened in the factory) will not give pinholes from carbon dioxide release from post development acid baths. Pinholes are usually found if you don't prewet, don't properly agitate, or use a very very soft film or a high temperature with B&W.

PE

PE,

Do think we should be fixing our processed negatives with hardner, or is the factory hardened film sufficient?

Are you an advocate of pre-soaking film before the developer? I have always done this with Kodak films, however I believe Ilford recommends not pre-soaking.

Thanks.

 

[Brian Bullen]

No, I can say that properly hardened film (hardened in the factory) will not give pinholes from carbon dioxide release from post development acid baths. Pinholes are usually found if you don't prewet, don't properly agitate, or use a very very soft film or a high temperature with B&W.

PE

Thanks for the informative answer, it's always good to hear from someone who actually has experience. My only concern then is does a film like EFKE PL25 or X-Ray film have enough factory hardener?

Formalin? If I remember correctly that is basically formaldehyde.

 

[Photo Engineer]

I know that Fuji, Kodak and Ilford films are hard enough when they leave the factory. IDK about others.

PE

 

[PhotoSmith]

Thanks everyone for your responses.

 

[jeroldharter]

What about Nacco

For no very good reasons, I use Heico (Brandess now?) HT5 fixer for film and Ilford Hypam for paper fixer. When I look up the various fixers, the Nacco brand always seems to be the cheapest and seems similar to the rest of the rapid fixers. Does anyone use Nacco fixer? Because it is cheaper, why not use it exclusively?

 

[kiku]

Hi! Sorry to rain on your parade but "Kodak Rapid Fixer" does not contain hardner. The package contains parts A and B. Part A is the fixer and part B is the hardner. If you want a non-hardening fixer use part A only; if you wish a hardening fixer add part B to part A.
Cordially, Howard Tanger

I have some questions about film fixers. ...
Kodak's Rapid Fixer contains hardner.....
Thanks in advance for your replies.

 

[Photo Engineer]

So, Kodak Rapid fixer as packaged contains hardener. The use of it is optional, but the package does contain it.

PE