Shot fixer bleaching out image?

[Ivo Stunga]

Hello and here are some of my observations - I don't know where I want to go with this thread currently, but hear me out.

Yesterday I did my usual BW reversal and at the re-exposure stage to light I was admiring how well Kentmere 400 pushed 2 stops reversed to positives, keeping blacks solid black and looking mighty fine. So I was expecting great EI1600 slides to project at the end, but ended up with washed out blacks - irregularly washed out that is - looks as if the blacks had been painted on with careless brush strokes if I had to describe the random visual effect. Edit: cloudy is the word I guess. "The fuck" I was wondering and said loudly, "What happened?" I have not deviated from my working methods, so something is shot. Is this the work of that suddenly clouded and sulfur-smelling fixer?

So the next time around after reading the following statement about fixing in Ilford Reversal Processing (reversal, mind you): "This is an optional stage which removes any last traces of silver halide that did not develop and leaves the image clean and fully transparent in the clear parts", I decided to skip fixing to have a control to compare against. After all was dried I was able to isolate the suspected fixer as the culprit.
Unfixed slides look fine (as expected) and have a lovely sepia tone to them that I really dig and want to explore further. Blacks are where I remember putting them, but the fixed slides have however completely washed out blacks (unacceptable) and no tint to them - completely grayscale which is interesting.

That got my ill-educated (in the arts of darkroom) brain put together 2 things:
1) I have sodium hypo as silver solvent that some films need to clear out properly to the base. It can be also tasked to... remove any last silver halides, right? Isn't that what fixers do?
2) I have sodium pyrosulfite I bought trying to stabilize permanganate bleach (dropped that).

A quick YouTube session later I now have an info that these put together make a pretty decent, slowly acting and stable "Hypo Fixer". And considering the "optional" nature of it, I decided it wouldn't hurt to learn something new today too.

And here are my questions I want you to explore:
1) Does fresh fixer "bleaches" images too and I just never noticed it? Because I've read on some reversal paper that fixing can "eat" some highlight details away and therefore a much reduced fixing time can be recommended. It stuck in my mind. And I did fix for a minute longer, got more of that lovely bleaching effect.
2) Am I thinking right that switching from rapid to slow fixer could yield both benefits: control over potential highlight detail loss (if that's a thing) and over the sepia tint I got from PQ Universal? Or was this just a fluke? Which I highly doubt so, because the bleaching effect got progressively worse over time until noticed.
3) But damn, should I touch toners?

Anyhow, my fixer is obviously tripping balls (trying to fight his dark side) and I'll put together fresh one as instructed from chems I've got (sweet!) - sounds fun putting something together from raw chems that I usually relied on stores to get!

 

[Ian Grant]

Rapid fixer will bleach a film or paper image if it's left in the bath too long, but I suspect that the failure is mainly due to the push processing ;leaving a relatively weak positive image, it's also possible that reversal image wasn't fully developed.

Ian

 

[Rudeofus]

Bleaching effects are well documented in fixers, especially in acidic fixers. I have seen that myself: placed a developed sheet into fixer, stepped out of the darkroom for a chat, which turned into a looooong chat. In the mean time the paper curled up, which pushed the center part of of the fixer. An hour later the left and right hand side of the print was 30% bleached, while the center part looked mostly normal.

Notes:

1. I did not observe any bleaching in the 2-5 minutes the sheets were normally immersed in this fixer.
2. The fixer was Agfa 304, which is quite acidic. None of my neutral fixers ever did anything like this.
3. If fixer is about to go bad, it is about as acidic as it ever gets, and it may bleach faster than Agfa 304.

About the strong silver solvent in reversal first developers: these are often described as "clear out the highlights", which is what is observed about their action. Their main purpose in a reversal first developer is, however, not the removal of some undeveloped silver, but rather the acceleration of the developer. You can imagine a solvent as the inverse of a restrainer: it increases activity and contrast, and at the same time it creates fog. Obviously the solvent is not the only way to create contrast&fog, and I believe, that I have seen B&W reversal first developers without any solvent.

 

[Lachlan Young]

Kentmere 400 pushed 2 stops reversed to positives

As Ian said, there's your problem. If you look at the attached curve family for Scala 200x, you can see what happens to Dmax as you push further. The Scala process, as far as I can tell, uses a development accelerator to access the silver and has very low solvency in the FD.

What are you using for the first developer, reversal step and redevelopment step?

 

[Ivo Stunga]

I'd agree that's it's solely an effect of pushing the film if the effect didn't get stronger on the same film over the time I 1) discovered the funky smell and cloudiness and 2) reversed the previous 3 test strips that each progressively suffered more from this. I observed this fhe first time I do BW reversal (6 years) and the only difference I can think of is the smelling/cloudy fixer I experienced for the first time.
And unfixed slides have the density I'd expect - if it was overdeveloped, wouldn't the reduced density be apparent prior to fixing? They appeared dense and 27W CFL bulb I use for re-exposure was not visible through dark areas prior second development (tested saturated and fresh) and fixing.

Meanwhile I did some testing with the unfixed strip of film and freshly mixed Hypo Fixer. At the temp I was working with it, it cleared the PQ Universal stain in some 20s and film went clear to the base in 01:30.

And yes, I observe the slide getting lighter with Hypo fixer - but that's due to the warm tint/"filter" being removed, and the difference is within the expected boundaries.
What I did not observe in 2min Hypo fixing time was that cloudy pattern of irregular density/blacks, all fixed to an even, lighter tone.

For my first test of K400 I used the usual PQ Universal 1+5 + 1g hypo to make 500ml working solution, and second developer is PQ 1+9 as in Ilford recipe, and got changes in density based on where and if the film was fixed: funky smelling Ilford Rapid Fixer, left unfixed or in Hypo fixer.

If fixer gets more acidic nearing its exhaustion, the observed increase in bleaching effect would make only sense.

 

[Raghu Kuvempunagar]

I've tried exactly what you described - reversal processing of Kentmere 400 at EI:1600. Two stops push does kill DMax of this film to the extent that you get a pale slide. Even the esteemed DR5 process can produce a DMax of only 3.0 for this film and at EI:400. But I didn't get irregularly washed blacks. I used Dichromate bleach whereas you have used Permanganate bleach. I suspect the unevenness you got in the slides could be because of emulsion softening by the Permanganate bleach.

 

[Ivo Stunga]

Thanks for your input, but it begs a question - if it was an effect of permanganate bleach, wouldn't the poor density be visible during the reexposure stage? I use dilute (A+B as in recipe + additional water as part C) and for bleach for 5 minutes, it could withstand reloading in Patterson reel after reexpo with minimal edge marking damage.

I take the film out of reel completely to enjoy the creamy sight of it for 2 minutes and have an insight on how's it gonna be at the end - poor density at this stage usually means poor density at the end, but this had good (apparent) density before redevelopment / fixing and completely opposite after.

I'll buy some more K400 to test this out

 

[Raghu Kuvempunagar]

What I meant is the emulsion after permanganate bleach is soft and this might have led to some unevenness during the fixing stage.

 

[Ivo Stunga]

I see, but I use quite dilute: A+B as in recipe + water as part C - do you think it's a possibility even this diluted?

I'm starting to lean on possibly thay it could be an unsuccessful marriage of poor blacks at EI1600 (to be expected to a degree) and funky fixer (funky cloudiness).

 

[Ivo Stunga]

I believe, that I have seen B&W reversal first developers without any solvent.

There are films (clear base Rollei and Adox comes to mind) that reverse completely with straight PQ 1+9 without any hypo.

To arrive at development times and hypo for films I haven't shot, I usually end up cutting them in 4 strips to have 4 different development tests from a single film. Tedious, but gives results.
I start with PQ 1+9 with no hypo added, complete the reversal and evaluate the completely dried strip (some films darken quite a lot when dry). If it's too dark, I add 0.5g hypo to the 500ml developer for second strip, then additional 0.5 to the next (if required) until I like the result.

Rollei Infrared 400 is good without any hypo for example: https://www.flickr.com/search/?user_id=108634366@N07&tags=Infrared400

 

[Ivo Stunga]

Hello and just wanted to inform you guys that this did happen again with hypo fix that sat untouched for a month.

Again the bleaching effect did occur in 2min fixing time and replacing the fixer solved this issue completely, now blacks are dense and solid, all good.

Moving forward I have to pay extra attention to my fixer, noted.

This time around emulsion damage did occur with my 1/3 dilute Permanganate bleach for 6 minutes, will bleach for 5min next time around and I'll be great!

Details here

EDIT:
Reformatted the false media tag (but it didn't let me, reformatted again as media!)

 

[koraks]

Ivo, for what it's worth - the other day I was bleaching some 4x5 negatives and noted that the resulting silver halide was rather opaque. If this was combined with some actually developed silver, I would have easily mistaken it for an unbleached negative. In fact, as bleaching progressed, the progress was kind of hard to see because of this effect - transmissive dmax remained very high throughout the process, even though final bleaching was complete.

This is just to put the possibility out there that the deep blacks you're seeing are not all metallic silver, but possibly partly silver halides - which of course fix out in a fixer step.

I find it's sometimes possible to see if there's a layer of silver halides 'hiding' underneath a developed silver image by observing the film from the backside and looking for the distinct greyness of silver halide. By this I mean looking at the reflected light; not looking through the film from the back, since that will just show a lot of density even if it's AgX instead of Ag.

 

[Ivo Stunga]

Thanks for stating this, will be looking for it the next time around. However, considering that the rest of the steps were untouched and 1:1, even agitation number, - just replacing fixer solved all there is to solve.

I am able to achieve similar consistency as the automated developers, because of an app I'm using + counting inversions in my head, and stabilizing 20C temperature in a 20l bucket where I keep all my reversal chems for the duration of reversal. So the bad fixer was the culprit.

 

[koraks]

Ok, gotcha - good that you seem to have this one sorted

 

[Ivo Stunga]

Agreed, it's nice. And it feels nice to drop some knowledge on this forum, from which I learned so much