exhausted fixer: what risks?

"Gianni Rondinini" wrote in message
...
snip lots

i'll, perhaps, fix my negatives with longer times and a slightly
higher temperature in the future.

Longer times in the fixer is alright, but try to keep all the chemicals
close in temperature. Don't develope at 68F and fix at 80F.


--
Ken Hart

Gianni Rondinini wrote:

On Mon, 06 Feb 2006 15:20:00 -0700, Tom Phillips
wrote:
snip..

i've never used hypo clearing wash agent: i'm just using a wetting
agent (agepon 1+200).

not refix. As far as refixing already washed and
[...]
thiosulfate complexes by using a hypo clear before
washing. Should also wash a good 10 minutes.

i'm beginning to think that i should consider starting using a hypo
clearing...

i think that adding some more info will help you understanding what
may be my problem.
1. i develop
2. a couple of rinses with fresh water (no stop bath)
3. fixing (see later for times)
4. inford simplified washing (2 rinses with water, 1 rinse with 5
agitations, 1 rinse with 10 agitations, 1 rinse with 20 agitations);
water is very expensive and limited here, this is why i chose this way
of washing my films.
5. a couple of minutes in wetting agent, while i wash tank cap and i
prepare the developer for next rolls.


You should use a stop bath. Using a stop bath
for 30-60 seconds (30 seconds minimum to allow
the acid solution to soak completely into the
emulsion) will prevent any developer carry over
which will weaken the fix and shorten it's
life/capacity. I also would never use a fixer to
exhaustion. And as others have commented fixer
isn't particularly toxic to the environment so
long as the effluent is treated by your local
Sewer/Sanitation District. Most photo chemicals
are easily handled by sewage treatment. A good
practice is to mix your used developer (alkaline)
and fixer (acid) together to neutralize them
before dumping.

Also, using a hypo clearing agent will shorten
wash times and improve washing efficaciousness.
I generally give a 10 minute wash with t-grained
films after 2-3 minutes in hypo clear. Your fill
and dump w/agitation rinse method is fine, so
long as you use enough rinses. But I would test
the results using the HT-2 wash/fixer residue test.

maximum capacity. IOW if you fix the first few rolls
for 6-7 minutes you would need to fix the remaining

kodak declares 2-5 minutes for tmax fix,

Not long enough...

then i usually fix the first
films about 3 minutes, the next ones 4 minutes, the following ones 5
minutes. i have seen that after 6 120 rolls of delta's, tmax fix seems
to be exhausted, then i'm not going any further than this.
*but*, last two rolls already seem to be a little bit violet-ish,
sometimes, so i was worried about damages my negatives could get by
this.

Like I say you can simply refix. The effect unremoved
silver halides will have on negatives that are improperly
fixed will be more pronounced the longer the time (i.e.,
days or weeks.)

you do or not its a good idea to fix these films
for 3 times the clearing time instead of the normal
recommended 2 times the clearing time for non
t-grain films.

i'll have a look at their clearing time: i had trusted in fixer
sticker instead of checking it by hand.

thanks for your reply.
--
Gianni Rondinini (30, tanti, RA)
Nikon user - Bmw driver
http://bugbarbeq.deviantart.com

"Gianni Rondinini" wrote in message
...
On Tue, 07 Feb 2006 02:13:12 GMT, "Richard Knoppow"
wrote:

Peter Irwin's advice about 2 bath fixing is a very good
idea. The capacity of single baths to handle tabular grain
[...]


thanks for your long post. i'm going to print it
immediately and will
read it during lunch pause or this evening.

regards,
--
Gianni Rondinini (30, tanti, RA)
Nikon user - Bmw driver
http://bugbarbeq.deviantart.com

A correction: the quantity of Potassium Iodide for the
fixer test solution is given in milliliters, it should be in
grams.


--
---
Richard Knoppow
Los Angeles, CA, USA

"Gianni Rondinini" wrote in message
...
On Tue, 07 Feb 2006 02:13:12 GMT, "Richard Knoppow"
wrote:

Peter Irwin's advice about 2 bath fixing is a very good
idea. The capacity of single baths to handle tabular grain
[...]


thanks for your long post. i'm going to print it
immediately and will
read it during lunch pause or this evening.

regards,
--
Gianni Rondinini (30, tanti, RA)
Nikon user - Bmw driver
http://bugbarbeq.deviantart.com

Oh dear, a couple of other notes.
Testing fixer. A very good test for fixer is to measure
the clearing time of the film you are using when the fixer
is fresh and unused. Then measure it occasionally as its
used. A small clip of film is all thats needed. Soak dry
film in plain water for about 2 minutes before putting it in
the fixer. This is because dry film fixes at a slightly
different rate than wetted film. The old rule of thumb was
to discard the fixer when the clearing time doubled. This is
probably too liberal for a single bath but is probably about
right for the first bath of a two bath fixing system. Again,
the best test is the residual silver test because this is a
direct measure of the completeness of fixing.
The rule of thumb for fixing time is twice the clearing
time. This is fine where a fresh single bath or a two bath
fixer is used. However, as fixer becomes more loaded with
dissolved silver there may not be enough free thiosulfate
ions to complete the fixing processes in any length of time.
For tabular grain films in sodium thiosulfate fixer three
times the clearing time may be a better rule but I have not
found excessive silver using the sulfide test after double
the clearing time. A little extra time will not hurt.
For paper there is a danger of slight bleaching of
highlights when film strength _acid_ rapid fixer is used. A
neutral rapid fixer, as sold for color processing, does not
have the bleaching effects. The main reason a weaker
dilution of rapid fixer is given for paper is to avoid this
problem.
Determining fixing time for paper is not so simple as for
film because generally clearing can not be seen easily.
However, the sulfide test works fine. If you are in doubt
about fixing time takes several small test strips of paper,
soak them for a few minutes and fix them for various times
(mark them on the back). The wash as usual (or use a wash
aid and wash as usual). Then test with the sulfide solution.
The first strip with no stain will be tell the minimum time.

Another after thought. For a final rinse for film I have
been using a solution I first saw suggested by Micheal
Gudzinowicz.

Clean water 1.0 liter
Isopropyl Alcohol, 70% (rubbing alcohol) 35.0 ml
Kodak Photo Flo 2.5 ml

Soak the film in this for 1 or 2 minutes with occasional
agitation. Then hang up to dry without squeegeeing.
If stronger Isopropyl is used adjust the amount according to
the percentage.
Use rubbing alcohol that is just alcohol and water, not
the kind flavored with oil of wintergreen.
The Photo Flo is used at half the strength that would be
used alone. The combination of the Photo Flo and alcohol
makes a sort of super wetting agent.
If you must wash in dirty water this final rinse will wash
off any junk on the film when made up with clean water.


--
---
Richard Knoppow
Los Angeles, CA, USA