ph a measure of exhaustion???

RalphLambrecht · Jan 26, 2012

i noticed a change in ph in developer fixer and other working solutions over time. is there any rule of tmub at which ph these solutions are no longer usable?

johnielvis · Jan 26, 2012

probably--I've noticed that when I started using stop bath (used to water rinse afer development--now I use the same water rinses but also add a short stop bath step)....the fixer last CONSIDERABLY longer...I use very powerful developers for reversals and even with a LOT of water rinsing, the fixer was getting weak very quickly--this is just for the final "cleanup" fixing step when there's hardly anything left to fix--now with the stop bath after the second deveoplment, the fixer lasts and lasts and lasts---as it should since it's hardly getting used.

markbarendt · Jan 26, 2012

I've often wondered why there isn't an "indicator" fix like there is with stop.

Photo Engineer · Jan 26, 2012

It depends strongly on the initial pH value of each solution. A change of 0.5 units may be big or small depending on the starting value, so at 8.5 a change to 8.0 might be critical for a developer but at 10.5 it might be minor and then again it might not. Sometimes only trial and error can teach us these things.

PE

anikin · Jan 26, 2012

markbarendt said:
I've often wondered why there isn't an "indicator" fix like there is with stop.

What a great idea! If it's possible, it would make a great product. I also wish there was an indicator for the wash water as I wash my prints. I love the way pot. ferri bleach washes off. You can always tell whether you washed enough. What I noticed that it takes much longer for the water to lose that yellow tint than I would have expected. Somehow it makes me feel that the recommended wash times for RC papers are just a hair too short. Especially when doing large prints.

Photo Engineer · Jan 26, 2012

There are indicator solutions. Use the retained hypo and the retained silver test solutions. The problem is that the test solutions cannot be added to the wash or the hypo in the same way or they do bad things. But, they do work.

Also, the hypo exhaustion test solution is quite good but very qualitative.

PE

anikin · Jan 26, 2012

Yes, I have the HT and silver test solutions. I'm just too lazy to use them on a regular basis. It would have been so much more convenient to add a drop of indicator to the wash basin and wait for the water to clear again. Then I would know that I'm done with the wash. I guess I'm just dreaming here.

Photo Engineer · Jan 26, 2012

Unfortunately, the test solution stains prints.

And a pH indicator is useful, but you would have to have one for every fixer there is. There is no real indicator for hypo other than the test solution which is Silver Nitrate itself.

PE

Gerald C Koch · Jan 26, 2012

Since pH can change due to other factors I really don't think that this is a practical approach at least for fixer. Hypo test solutions like FT-1 aren't very good. They only give a positive reaction long after the fixer is really exhausted.

I have found that the best way to determine whether a solution is good or not is to keep track of its usage and age. HCA and stop bath are so cheap that I never make an attempt to keep them past a darkroom session.

johnielvis · Jan 28, 2012

I just have junk film ruined by accidents and not developed laying around in a coffee can...before I want to use the fix...I check the clearing time first by using a teeny strip of film in the fix and timing it.

OH...be sure to soak the film in hot water for 5-10 minutes to remove the dyes/backings so you don't color and foul yor fixer

Kirk Keyes · Jan 28, 2012

johnielvis said:
OH...be sure to soak the film in hot water for 5-10 minutes to remove the dyes/backings so you don't color and foul yor fixer

That sounds like a recipe for disaster!

And the dyes don't hurt anything, and they do fade with time anyway so who cares?

removed account4 · Jan 28, 2012

markbarendt said:
I've often wondered why there isn't an "indicator" fix like there is with stop.

there is !

if you use spring developer, stop, fix ...
when the stop indicates, it also indicates the fix needs to be changed

Photo Engineer · Jan 28, 2012

Ummm, John, that is not entirely correct. Sorry.

The exhaustion of stop depends on volume, type (ie. Buffer capacity), and work flow including developer pH and carryover.

It also depends on whether you are doing RC or FB prints or film.

So, the two do not dance in harmony sorry to say.

PE

Sirius Glass · Jan 28, 2012

johnielvis said:
OH...be sure to soak the film in hot water for 5-10 minutes to remove the dyes/backings so you don't color and foul yor fixer

This is a good way to get the emulsion to slide off the film and drop to the bottom of the tank or tray. Then you can pull, stretch or twist the latent image into any shape or form that you want.

removed account4 · Jan 28, 2012

Photo Engineer said:
Ummm, John, that is not entirely correct. Sorry.

The exhaustion of stop depends on volume, type (ie. Buffer capacity), and work flow including developer pH and carryover.

It also depends on whether you are doing RC or FB prints or film.

So, the two do not dance in harmony sorry to say.

PE

hi ron

sorry to be contrary ...
but paul krot the founder of sprint designed the chemicals to be used as a system ..
so the stop indicated everything, not just the stop ..

you could call and ask them yourself if you want
or just go to their website

Dead Link Removed

look under "The Sprint System "

john

Photo Engineer · Jan 28, 2012

John, I'll have to stand by what I said unless the instructions for mixing are drastically different for FB, RC and film. The diifference between 100 mg of silver vs 300 (paper and film respectively as an estimate) will effect drastically different effects on stop and fix and I know this from years of hard labor in the lab. The carryover from an 8x10 into 1L of stop is far from the carryover of 1 8x10 sheet of film, but the burden on the fixer is far higher with the film than the paper.

Just think about it and you will see.

Of course, if you design for the worst case, then you are essentially overdoing it for the most favorable case. In this event, you are pretty much making it work but are wasting chemistry. This then, becomes s force fit.

It also forces one to use just a single brand of chemistry to get this grandiose plan to work, and it probably does not. With all of their R&D, one would think that Ilford or Kodak would have done that years ago, but they did not because it was too precarious IMHO.

PE

removed account4 · Jan 28, 2012

sorry ralph for de-railing your thread !

ron

i am sure you are right about the chemistry you are using
but sprint was designed to be used this way
and since the 1970s people have been using the dev/stop/fix combo
as a system in schools and darkrooms all over the place and never had any trouble.

i don't think it is grandiose at all ... it is their system, and it works ...

as i said, if you don't believe what the company says
or you think they are disinforming photographers, schools and
people who use and love to use their chemistry, you should speak with them
and ask if they are just making it up.

i have spoken with them, on many occasion and they have been nothing but honest
and helpful. as a matter of fact, when the good folks at kodak professional gave me poor advice
paul krot at sprint reversed my misfortune and saved my skin.

john

Photo Engineer · Jan 28, 2012

If it works for you, use it.

PE

RalphLambrecht · Jan 29, 2012

jnanian said:
there is !

if you use spring developer, stop, fix ...
when the stop indicates, it also indicates the fix needs to be changed

not a bad idea

RalphLambrecht · Jan 29, 2012

Kirk Keyes said:
That sounds like a recipe for disaster!

And the dyes don't hurt anything, and they do fade with time anyway so who cares?

they also wash out with hca and extended washing, but as you alredy said. they don't do any harm anyway.ignore them.

johnielvis · Jan 29, 2012

RalphLambrecht said:
they also wash out with hca and extended washing, but as you alredy said. they don't do any harm anyway.ignore them.

actually, I've found that the crap that I can take off ... (not boiling...like 100 degree--processing hot temp...--completeley savfe and film is designed for it)....ANYWAY...I used to put it in and get the colored fix, but there' sother stuff that gets in there and makes like a slime on the bottom of the fix jar

whatever...I got rid of the slime and my fix is nice and pure and not contaminated...you wanna not presoak junk film go ahead...it's just less crap that gets in the fix---less crap equals longer life.

boy...all the people that never tried it say it's dangerous....I do it and it solved my extra fixer deposits problem..never a problem with emullsion sliding of never a problem with anything except an extra couple of minutes...which I let it soak in the jar of "hot" water while I set other stuff up

but whatever...you all certainly sound like you know better......

Bill Burk · Jan 29, 2012

To the original question, Ralph, I couldn't find specific recommendations for pH upper- and lower- control limits. Just Todd-Zakia included example control charts that tracked sensitometry and pH over time. They explained that the sensitometry would give you the heads-up that "something" was wrong. And the pH might lead you to the root cause.

ph a measure of exhaustion???

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