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Advantages of acid fixer?

sbriza.com

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Hi all,
I have heard about a lot of advantages of alkali fixer. But if it so better, why the acid fixers are so spread? Especially commercial products like Ilford Hypam, Foma fomafix.

Is it any benefit for using acid fixers?
 
????????????
I normally mix my own TF3. easy and wash with water, not a stop bath.
The cookbook states Ammonium thiosulfate is 20 - 30 % faster than Hypo however it is easier to wash out an alkaline fixer than acid fixer (paper). I would suggest using alkaline fixer. It is very easy to make.
Pat
 
I too would like to know why acid fixers seem to be more popular.
 
One possible advantage of an acid fixer is that you do not need a running water rinse, but just a still bath of acid stop—so no need to turn water on and off throughout the printing session.

Both fixer types work great.
 
There is a lot of mythology and very little real information about this. Certainly acidity will help stop development. I _think_ that acid fixers do a bit to protect against unwanted stains. Some say they last a bit longer. On the down side, they are more difficult to wash out.
 
Photo Engineer said:
There are several long threads on this topic on APUG.

PE
Click to expand...

I read Anchell´s Darkroom cookbook and of course also this forum, but both here and in the book there are mentioned only benefits of using alkali fixers, not acid.

But the acid fixers must have some benefits if they are so spread and most available commerical fixers are just acid like Ilford fixer, Fomafix etc.
It´s a little weird, isn´t?

Simply I would like to know the reasons of manufacturers to offer mostly acid fixers.
 
jmcd said:
One possible advantage of an acid fixer is that you do not need a running water rinse, but just a still bath of acid stop—so no need to turn water on and off throughout the printing session.

Both fixer types work great.
Click to expand...

Not having to run water is a big advantage for me.

By acid stop do you mean just a water bath or do you use something special?
 
Posted wirelessly..

A water stop is just that. You employ it for a longer duration than an acid stop. As to the acid fix, if you use a typical alkali dev, the acid fix is much more effective in halting development as you neutralize it, thus requiring much less rinse.
 
As the vast majority of fixers are acidic, wouldn't What's the Advantage of an Alkaline Fixer? be a better question?



Steve.
 
Steve Smith said:
As the vast majority of fixers are acidic, wouldn't What's the Advantage of an Alkaline Fixer? be a better question?



Steve.
Click to expand...

Isn't the advantage of alkaline fixer (vs acid fixer) the disadvantage of acid fixer. But the original question was for the advantage of acid fixer. Let's stick to the original question. I really would like to hear opinions on that subject. I add mine:

1. works better with hardener (historic benefit of lesser importance today)
2. abruptly stopping development and therefore more controllable development time
 
Acid fixers were the first and most popular fixers due to the fact that Alum could be used as a hardener for the early soft films and papers. It was also easier to use with a stop bath or water rinse, as it really aided in stopping development.

Today, with water supplies being more limited, alkaline fixers have become popular and photomaterials are hard enough to be processed without a hardening step of some sort.

Both acid and alkaline fixers should use a running water rinse after development or use an acidic stop bath to prevent contamination of the fix with developer and raising the pH.

PE
 
Prep For Fix

jmcd said:
One possible advantage of an acid fixer is that you do not
need a running water rinse, but just a still bath of acid stop
—so no need to turn water on and off throughout the printing
session. Both fixer types work great.
Click to expand...

The only reason for a stop bath of any sort is to prepare the
film or paper for the fixer. If the film or paper needed no
preparation then no stop would be needed.

I've eliminated any stop twixt developer and fixer by
using one shot very dilute chemistry. My fix is very
nearly neutral. Due to it's one-shot use the carried
forward very dilute developer does no harm. Dan
 
Ever Test for Tolerance?

RalphLambrecht said:
I use it to protect the fixer against developer contamination.
Is that what you meant?
Click to expand...

Ilford's and Kodak's suggested 10 or 30 second rinse is
primarily intended to impart an acidic character to the
film or paper prior to their encounter with an acidic
fixer. Of course some lessor or greater amount
of the developer is left in the stop bath.

In practice I doubt there is any real danger in having
the fixer load with developer as long as the developer
is inactive. So, the maintenance of the acid fix by
the acidic stop.

Were I processing in the usual way I by skipping the
stop would test a neutral to alkaline fixer's tolerance
for carried forward developer. Personally I believe
the need for a stop is over blown. Dan
 
The purpose of a stop bath is to stop development. A side benefit is that it protects the fixer from contamination.
 
nworth said:
The purpose of a stop bath is to stop development. A side benefit is that it protects the fixer from contamination.
Click to expand...

That's one way of looking at it, but if you skipped the stop bath altogether, the fixer would stop the development without any help from the stop bath. However, the developer would contaminate the fixer too quickly. Therefore, I use the stop bath to protect the fixer against developer contamination.
 
dancqu said:
...Personally I believe
the need for a stop is over blown.
Click to expand...

For film, I agree, because I use developer and fixer one-shot. For paper, I want a stop bath in-between developer and fix to protect the fixer against developer contamination. A wet 11x14-inch print contains about 30 g of developer. Thoroughly letting it drip off reduces this amount to about 15 g, but that still means about 8 ounces every 25 prints. Admittedly, there is no total exchange of liquids, nevertheless, I don't want that in my fixer.

People who use an indicator stop bath get a visual clue of this problem, because they often notice how the fixer slowly turns yellow. This is caused by the yellow color of indicator stop bath residue carried over into then fixer.
 
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