Can I leave film in stop bath for 7 minutes?

[Pere Casals]

A couple of observations about best practice:

First, overfixing film or paper is not a good idea. Pere, you might have been able to get away with leaving a negative in the fixer overnight, but I'm willing to bet that the shadows bleached a tiny bit (especially if you use a rapid fix). That said, film and RC paper don't have the problem of fixer soaking into the paper base and can be fixed longer than the minimum needed for full fixation without any problems up to the point where bleaching starts to be a problem. I, like Pere and many others, fix T-Max films for substantially longer than needed to better remove the pink dye. Where does bleaching start to be a problem? That depends on your negative and the type and dilution of fixer you use. An overexposed neg might even benefit from a little bleaching... However, wet time should be kept to a minimum. Holding film in any fluid for hours risks damaging the emulsion.

Plaubel, I'm not sure what you mean about getting "blank film" after six minutes of fixing. If you're saying that six minutes in the fix completely bleached away the image, I think you may be mistaken. The most aggressive fixers I know don't bleach appreciably until much, much longer than that. I also don't know what you mean by paper changing "tonality" after "long stopbath sessions." I can imagine some papers, especially fiber-base papers, becoming stained by the indicator in the stop bath, making the whites yellower. As for the silver image, I simply can't imagine that a weak acetic or citric acid solution is going to affect it in any way, even with very extended exposure.

As for "lights on" after the film/paper is in the acid stop for a few seconds. Two things happen here. First, as Pere notes, the development activity has been effectively halted, meaning that if the fixer is acid as well, you could flip on the light after a few seconds in the stop and do the rest of the processing in room light (watching the film/paper clear in the fix is informative and fun). There are some caveats here, however. Many materials, notably papers, will "print out" with exposure to light after some time. If the light source is strong enough and the fixing step is slow enough, you can fog papers and films by doing this. If you use an alkaline fixer, any developer carried over after the stop step will be reactivated in the alkaline environment. If you've turned on the lights during the stop step, you've just exposed the rest of the paper/film and it will begin to develop again in the alkaline fix, fogging and streaking it till whatever developer left in the emulsion is exhausted. Don't ask me how I know this

Best practice is to leave the white lights off until the film/paper has been in the fix for half the total fixing time. You can get away with less, but it's not best practice and, with papers, you can fog the whites. Film is less susceptible to this effect, so you may see no difference in fb+f when using acid stop and fix. Pere, if you've tested your workflow with a precision densitometer, then there's no reason not to complete the last film-developing steps with the light on. I would never do that with a print, however.

Back to the purpose of this thread: If the OP stops some film sheets before others and lets them sit in the stop bath while the others finish developing, there should be no ill effects. Again, I simply can't imagine any damage to the image from a few extra minutes in a weak acid solution. Testing this workflow is easy, so should be simple to confirm or refute.

Best,

Doremus

Thanks for that information. It is allways great to learn from masters.

I was aware of possible bleaching effect with very low ISO film CMS 20, warns about it. I think it can be interesting to know at what point tiny bleaching effect of overfixing can be seen. Now I'm learning to calibrate film/paper and I'm to complete extensive tests, so I'll include overfixing some contact copies of the stouffer gauge in order to measure this effect with precission.


About paper, I think I remember (not sure, I can be well mistaken) that paper emulsion may contain hydroquinone as a preservative, that of course do not work as a developer until in wet alkaline medium...

Perhaps that deep hydroquinone remains in paper until fixing or washing, and it gets active again if fixer is alkaline. Just guessing...

With film, my informal tests showed me that film can be fixed lights on with no side effect. Still I'll check it well with a contact print of the Stouffer !

[Sirius Glass]

Stop bath is only needed for 30 seconds to a minute. After that move it to a water bath and let it sit or use a diluted stop bath.

[plaubel]

Doing it in darkness if ok, but if you want to know if it is necessary, this has a cost of two sheets.

Peter, I'm absolutely sure that your technique works with your materials, but after making other experiences myself, I further would not say that light on is a good idea in general.
Seems to depend on different circumstances and the material in use, like you described with Adox 20.


Doremus, some years ago fixing my film with usual times like 6 or 7 minutes ( an eastern film from russia called Tasma, a technical film), I have had problems; the film didn't become totally blank, but I was able to wipe the emulsion with my fingers.
After discussing this problem with an experienced guy, Mr. Coffenol, it was clear to me that thin layer film needs less fixing time - and then it worked well.
This showed me something, and as you have said before, in using chemicals I try to hold the recommended times.

"" I also don't know what you mean by paper changing "tonality" after "long stopbath sessions." ""

It's easier to me to bring a real example than describing in english, so please let me bring an example next days :-)

"" Just leave a sheet all night long in the Stop bath lights open...""

I love science, so I will do this together with the paper longstopping.

Best,
Ritchie

[plaubel]

After rereading, I have to add that I don't use an acid fix, and I want to note that I use citrus acid for stopping processes.
Ritchie

[Doremus Scudder]

After rereading, I have to add that I don't use an acid fix, and I want to note that I use citrus acid for stopping processes.
Ritchie

Ritchie,

You likely don't want to expose your film to light until well into the fixing process then. It would almost certainly fog it due to carried-over developer reactivating in an alkaline fix. Many don't realize that developer chemicals don't get washed out in the stop, just neutralized and will come back to life in an alkaline environment.

Doremus

[Mrportr8]

I add film to the developer at different times so they all come out at the same time. It simplifies everything else. To the rest of you, whatever works. The important thing is the end result and if you're satisfied.

[Pere Casals]

Ritchie,

You likely don't want to expose your film to light until well into the fixing process then. It would almost certainly fog it due to carried-over developer reactivating in an alkaline fix. Many don't realize that developer chemicals don't get washed out in the stop, just neutralized and will come back to life in an alkaline environment.

Doremus

Doremus, if sinking the paper in developer by using the clamps that are in the stop bath it happens that those areas that got in contact with the stop liquid do not develop at all, delivering perfect white stains.

From this, I looks to me than contact with stop bath prevents than any development can take place after. Perhaps a test may be made...

Pere

[plaubel]

Ritchie,

You likely don't want to expose your film to light until well into the fixing process then.

Thanks, Doremus.
That's exactly what I have told before, but probably for other reasons.
Exposing after a 10 second stopbath may not function in any case.

Usually developing, stopping and fixing in darkness, I haven't seen the reactivation of silver under light and in alcaline fix, weither in the dark nor in my experiments, so I have to lighten the scene next.

I know that the acid of the stopbath is only a stopping agent, which does not protect the silver.
Fixing will wash out the remaining silver, but during this process there come out some new chemicals.
That's the reason for doubling the clearence time - we want to wash out this new products, too.

Tomorrow I will enter my darkroom with an uncommon todo list...

Best,
Ritchie

[Pere Casals]

Thanks, Doremus.
That's exactly what I have told before, but probably for other reasons.
Exposing after a 10 second stopbath may not function in any case.

Usually developing, stopping and fixing in darkness, I haven't seen the reactivation of silver under light and in alcaline fix, weither in the dark nor in my experiments, so I have to lighten the scene next.

I know that the acid of the stopbath is only a stopping agent, which does not protect the silver.
Fixing will wash out the remaining silver, but during this process there come out some new chemicals.
That's the reason for doubling the clearence time - we want to wash out this new products, too.

Tomorrow I will enter my darkroom with an uncommon todo list...

Best,
Ritchie

Just a quote from Roger Hicks, "British author of more than 30 photography books" (http://www.rogerandfrances.com/)

He says:

"You can transfer the film from a tank of dev to the fix tank by room light.
The few seconds exposure as you pull the film out of the developer and drop it into the fixer tank will not cause detectable fogging, because the induction period of the second development is longer than the time available"

Anyway this is something way easy to test.

Also we can test the practical induction time, this is taking a film end, with lights open, then introducing the film in the developer in steps of 5 seconds, and then stop+fix. At some developing time step some fog will appear.

Regards

[LabRat]

Just a quote from Roger Hicks, "British author of more than 30 photography books" (http://www.rogerandfrances.com/)

He says:

"You can transfer the film from a tank of dev to the fix tank by room light.
The few seconds exposure as you pull the film out of the developer and drop it into the fixer tank will not cause detectable fogging, because the induction period of the second development is longer than the time available"

Anyway this is something way easy to test.

Also we can test the practical induction time, this is taking a film end, with lights open, then introducing the film in the developer in steps of 5 seconds, and then stop+fix. At some developing time step some fog will appear.

Regards

I don't exactly know the fact or science of this, but when clearing a lot of old film in fix while in roomlight, one thing I have observed is that film cleared in the dark tends to clear a little faster and clearer (without the slight pink cast, that is from a trace of finely divided silver left on the material), and even with the accepted practice of turning the lights on halfway through the fixing stage, it seems to clear better/faster in the dark, so it seems that exposed free silver is a little harder/more stubborn to fully clear in my rapid fix IMHO...

Steve K