Stop Bath exhausted or developer reactivated in alkaline fixer?

[ericdan]

I've asked this question here before on another thread while talking about processing fiber paper.
Since this is about Film, I thought I'd start a separate thread.
I was trying to see if I could inspect my developed film with room lights on after having stopped development in a Ilfostop.

• Tri-X
• Xtol
• Ilfostop
• Moersch Alkaline Fixer

1. Developed the test strip of film as I usually do.
2. Stopped it for twice the usual amount of time to be sure development has stopped.
3. Opened the tank and dipped the film strip into the alkaline fixer

I could see some parts of the image appear but the developer seemed to reactivate in the fixer. The film slowly turned completely black in the fixer.
Does that mean my stop bath was exhausted or the developer carry over got reactivated? The indicator stop bath was still bright yellow. I assume that part was fine.
If that's the case I need to reconsider Alkaline fixer as this seems to add unwanted development time to my film in the fixing stage. (the same for paper I assume)

 

[MattKing]

The stop bath stopped the development.
No further development would have occurred in the fixer if you hadn't turned on the lights.
But if you are using an alkaline fixer, development of the newly exposed film can happen. The previously (in the camera) exposed parts of the film have most likely already developed out.
The other thing to be aware of is that as fix clears the film it changes the appearance. What you think is additional density may just be the increase of visibility as the unexposed silver halide is fixed away, leaving the exposed and developed silver.

 

[M Carter]

I do this when lith printing all the time (with rapid fix though). Acid stop, and a solid rinse in running water, turn the light on to see how the fix affects the print. Never get any fogging, my brain says it would be impossible for more development to happen and some time before silver staining could occur.

If you try this again, maybe try a very good rinse after the stop. I do that all the time to keep the fixer clean, with paper or with film, I never go right to the fix without a rinse.

 

[ericdan]

That makes sense. Once stopped and washed it should be impossible to have development start again.I'll try a thorough rinse before the fix.

 

[Doremus Scudder]

If you need to turn on the white light before the film is at least fixed for 50% of the fixing time, you can't use an alkaline fixer. The light exposes the rest of the unexposed silver halides before they've been fixed out and the carried-over developer, now in an alkaline environment and active again, goes to work on them. (BTW, if your indicator stop is still bright yellow, and mixed to the right strength, then it is still good.)

I had similar problems with TF-4 and a bit of a light leak near the fixer tray; got streaks and fogging till I found the light leak (a small crack in an otherwise light-tight window covering. I tend to use Ilford Rapid Fix these days anyway, just to be on the safe side.

However, I have (as a demonstration) done exactly what you are describing: After removing the film from the stop, I turned on the white light so everyone could see how the unfixed film looked, then proceeded to fix the film (in an acid fix) and watch it clear. It's kind of cool to do for those just learning B&W processing, but in real life I like to fix for 50% of the fixing time before turning on the white light.

Best,

Doremus

 

[MattKing]

That makes sense. Once stopped and washed it should be impossible to have development start again.I'll try a thorough rinse before the fix.

Why?
Until fixing is complete, there are still unexposed and therefore undeveloped silver halides in the emulsion. Neither stop bath nor a rinse removes them. If you expose them to the light, they will be capable of development. So if there are even traces of a reducing agent left in the emulsion, they will develop the newly exposed silver halides.
An alkaline fixer wouldn't be the best environment to cause the newly exposed to be developed, but it certainly is more suited to that then an acidic fixer.

 

[jim appleyard]

I'm not sure why you're doing this, is it development by inspection? Curiosity? Here's a good article about DBI: https://unblinkingeye.com/Articles/Inspection/inspection.html

 

[ericdan]

I had quarter of a roll left and just wanted to try out of curiosity.

 

[ericdan]

I had quarter of a roll left and just wanted to try out of curiosity.

 

[jim appleyard]

I had quarter of a roll left and just wanted to try out of curiosity.

OK, that's as good a reason as any!