Can I Reuse F-5 Fixer and Acid Stop Solution?

External Since: Jan 05, 2005 Posts: 108

I decided to throw away D-76d 1:1 developer every time after
processing. But for the fixer and stop solution, can I reuse them? If
I can, how many times can I reuse them before throw out? Thanks

-
narke

External Since: Dec 03, 2004 Posts: 249

narke <steven.TakeThisOut@lczmsoft.com> wrote:
> I decided to throw away D-76d 1:1 developer every time after
> processing. But for the fixer and stop solution, can I reuse them? If
> I can, how many times can I reuse them before throw out? Thanks
>
I use stop bath one shot for film. Some people use indicator
stop bath which changes colour when the pH gets too high.
This is a really good idea if you intend to re-use stop bath.
Indicator stop is also valuable for giving you an idea how
long your stop bath will last in a printing session. (This can
be quite a long time with RC papers, but may be a surprisingly
short time with fibre based paper.) I generally use white vinegar
with a 1+3 dilution. Some people don't like the smell of
vinegar/acetic acid and use a stop bath made from citric acid
instead. Ilford sells a citric acid based stop. Other people
use a couple of quick changes of water instead of stop bath for film.

The safest way to re-use fixer is the two bath method. Make up
two bottles of fixer and mark them "1st" and "2nd". Fix for
half the normal time in the first bath, pour it back in the
bottle and then fix for the remaining time in the second bath.

You can determine fixing times by soaking a scrap of film in
water for a few minutes and then putting it in the fixer.
Normal fixing time should be at least three times as long as
it takes film to clear in fresh fixer. "Clearing" means that
the film no longer looks milky.

You can check for fixer exhaustion by examining the film after
the first fixing bath. It is safe to examine film in the light
at this point. If the film still looks slightly milky, the fixer
is exhausted. Dispose of the first bath, use the second bath as
your new first bath, and use fresh fixer for your new second bath.
After you have gone through several cycles you should replace
both baths.

To give you an example of how this works: I use Kodak Fixer
for film which I make up in a gallon jug. I have two bottles
which each contain a little over 600 ml. My normal fixing time
for hard to fix films like Tri-X and TMX is 12 minutes, for other
films it is 10 minutes. The fresh first bath usually lasts for
10-14 films, and the later first baths which were former second
baths last for 6-8 films. After I have finished the gallon,
I start with both baths fresh. This gives around 40 or so films per
gallon. If you use rapid fixer, your fixing times will be only about
half as long and the baths may last somewhat longer.

Rapid fixer (ammonium thiosulphate) is supposed to be better than
Sodium Thiosulphate based fixers such as Kodak Fixer (powder)/F5
for fixing modern films. I like Kodak Fixer anyway because I've found
that my films tend to dry flatter when I use it. This is not a
universal experience, some people find it makes their films curlier.

Rapid fixer is probably quite safe to use with a single bath
provided that you do not exceed the recommended number of films
per litre and you check the clearing time when you get anywhere
close to the rated capacity. If you chose to use the sodium
thiosulphate fixer, you should use the two bath method.
You should always have separate lots of fixer for film and paper.

Ilford's pdf file on their rapid fixer is good to read:

<http://www.ilford.com/html/us_english/pdf/Rapid_fixer.pdf>

Peter.
--
pirwin.TakeThisOut@ktb.net