Base Fog with Flexicolor Developer

[originalwinslow]

Greetings all, I have recently switched to using Flexicolor developer and am experiencing an issue with elevated base fog/D-Min compared to all the developers I've used previously. I was in contact with Kodak directly and they were unable to give me any good answers besides confirming my liter mix ratios were correct. They thought that the potassium ferricyanide bleach I use instead of the official EDTA could be causing cyan dye problems, but I have been using these chemicals for a year with consistent results and never seen this before. I ran a test strip through CS blix instead of the ferri bleach and saw no improvement. The developer has been pH adjusted to the 10.1 spec, no difference made there either.

I am using LORR developer replenisher without the starter. I am aware that the freshly mixed LORR is more active and can cause fogging in the first few rolls, but the issue has not resolved itself even after bromide seasoning with 20+rolls run through the replenished solution. I ran a back to back dev with CS powder developer and got a normal base D-Min, so it is not related to depleted bleach or fix.

All in all the developer is giving me acceptable results, but in some low-density sections of under-exposed negatives the shadows are quite muddy compared to other developers.

At this point I've run out of things to test. I had assumed that switching to Flexicolor would be an upgrade but that has not necessarily been the case. Here is an image comparing the CS powder developer (top) negatives to the Flexicolor (bottom).

If anyone has any ideas please let me know.

 

[koraks]

potassium ferricyanide bleach

Not the best idea, but I understand this is sometimes done to deal with unavailability of the proper C41 bleach.
If you must use a ferricyanide bleach, then use a stop bath followed by a sulfite clearing bath between the color developer and the bleach. This should avoid the excess dye formation resulting from instantaneous oxidation of carried-over developer in the bleach bath.

 

[originalwinslow]

Not the best idea, but I understand this is sometimes done to deal with unavailability of the proper C41 bleach.
If you must use a ferricyanide bleach, then use a stop bath followed by a sulfite clearing bath between the color developer and the bleach. This should avoid the excess dye formation resulting from instantaneous oxidation of carried-over developer in the bleach bath.

Hey koraks

Yep, you and I have run the full gamut of diagnosing issues with ferri bleach but the strange part here is the fog is not present when using CS developer. Kodak confirmed to me that the CS powder is chemically almost identical to flexicolor. Not sure why this would occur only with the EK chems and not the CS all other things being equal. It also did not ever occur with my DIY C-41 developer.

On a side note the contact at kodak commented that integrating the SS into the acetic acid stop bath is useless and actually diminishes the stopping ability of the bath. I mention this because someone (maybe you?) had previously said in another thread that stop/SS clearing could be combined.

I will try the separate clearing bath and see if that has any effect, although I do not think this is a developer crossover issue. In my experience, developer crossover into the ferri bleach created distinct staining and not a universal fog of the entire roll.

I also ran a strip through factory-made blix and it exhibited the same level of fog.

 

[koraks]

On a side note the contact at kodak commented that integrating the SS into the acetic acid stop bath is useless and actually diminishes the stopping ability of the bath. I mention this because someone (maybe you?) had previously said in another thread that stop/SS clearing could be combined.

Someone suggested it and I was one of the people who emphasized that no, the sulfite bath and stop bath can NOT be combined! So the info you got from Kodak is consistent with this. Btw, out of interest - have you been talking to Kodak proper, or to PSI? Kodak isn't the manufacturer in this case, after all.

In my experience, developer crossover into the ferri bleach created distinct staining and not a universal fog of the entire roll.

We've seen several examples recently on the forum where this was exactly what happened. So my guess for now is that you're still running into the same problem. There may be a difference between the CineStill powder and the PSI/Kodak liquid that plays a role here.

To be clear, have you been putting the sulfite into the stop bath up to now? Because that's indeed not the best idea. It's not so much that it will bar the stop bath from doing it's job; it's more that you basically destroy (some or all of) the sulfite by incorporating it into the stop bath, depending on how acidic the stop bath is. So it renders the clearing action ineffective; not so much the stop bath.

 

[Spektrum]

Someone suggested it and I was one of the people who emphasized that no, the sulfite bath and stop bath can NOT be combined!

I admit it. I was the one who suggested this several times. Perhaps a few others did too.

I also use Ferri Bleach.
I tried separating the STOP bath (2% acetic acid) from the clearing bath in sodium sulfite (20g/liter), as suggested by @koraks.
The results were consistent and very satisfactory.
I believe this is the best way and I can recommend it.

But I insisted on combining the STOP bath with the CLEARING bath for personal, (perhaps silly, reasons) – I use a sous vide machine to maintain the proper temperature of the chemicals.
The container of water in which I heat the bottles is too small to hold an additional bottle of sodium sulfite solution, and I really want each bath to be the same temperature so as not to shock the film with temperature changes.

That's why I've been successfully using the STOP-CLEARING recipe from this post:

Sodium Sulfite clearing bath in ecn2 process

I have been using vision 3 film for about three years. I mix my own chemistry. Until recently I never used Na Sulfite as a clearing bath after the stop or bleach step. I didn’t see a sulfite clearing step in the protocols published by Kodak. But after reading some old posts that suggested...

www.photrio.com

This recipe uses twice as much sodium sulfite (40g) and also includes sodium acetate, which buffers the solution, protecting the sodium sulfite from decomposition in an acidic environment.
The pH is suitable for stopping development (between 5.2 and 5.4).
I use this bath once (I throw it away after use) for both the C-41 and ECN2 processes.

In my case, I use FujiHunt EnviroNeg Developer 60 AC. I develop a maximum of 4 films and then throw it away.
It's cheap and there's a lot of it (10 l) , and I want to keep the results consistent.
Of course I use a starter FujiHunt C-41.

I'll probably buy Fuji Hunt C-41RA AC bleach by the end of the year. It's only about €80 for 5 liters, and this bleach should last me a long time.
I will still use the STOP bath after developing, but I will no longer need to use sodium sulfite.

 

[koraks]

This recipe uses twice as much sodium sulfite (40g) and also includes sodium acetate, which buffers the solution, protecting the sodium sulfite from decomposition in an acidic environment.

Yes, very good that you added this; I totally forgot and in this way i can see this works well. The buffered stop bath will be strongly buffered enough to still be effective as a stop bath, and at the same time it'll be mild enough for the sulfite to (at least largely) survive.

 

[Spektrum]

Thank you, but I must add one more very important piece of information.

This buffered solution should be prepared soon before starting the development process.
Sodium acetate works, but not forever.
I had a situation where I decided to develop color negatives over the weekend and prepared the chemicals.
Unfortunately, for family reasons, I had to abandon my plan.
I returned to the development after a week, and when I unscrewed the cap from the brown glass bottle containing the STOP-CLEARING solution, I heard the characteristic hiss of escaping gas.
There was quite a lot of it, and I smelled sulfur.
I poured it out and mixed the bath solution again.

 

[koraks]

Hm, that's odd; I would have expected the acetate solution to be stable.

 

[Spektrum]

I don't know. It was summer. That bottle was quickly put in the attic. It's very warm there in the summer, and there are two skylights.
Perhaps the sun was shining on that brown glass bottle and that caused the solution to become unstable.
There were too many variables, and too much at stake, to skimp on chemicals.

 

[koraks]

Maybe there was a minor mixing error involved and your acetate buffer ended up at a slightly lower pH (a little below 4.0). In that case there would be some sulfur dioxide gas being formed.

 

[Spektrum]

I'm too lazy to mix by hand. I use a very inexpensive (available in Poland for about 25 euros) Vevor magnetic stirrer.
It's an inexpensive stirrer, but it does the job well. I usually stir for about 15 minutes, even if everything has already dissolved.
I simply prepare other things I need for the development process during that time.

I measure the chemicals using a cheap jewelry scale, but this is the fourth scale I've tested, and it really does give repeatable results with an accuracy of 0.05g.
The manufacturer claims accuracy is 0.01g, but I use laboratory calibration weights before each chemical weighing and confirm its repeatable accuracy at 0.05g.

This is sufficient accuracy for me. Using a dose of 30g of sodium acetate per liter, it's unlikely that a measurement error could affect its performance.

But there's one important detail that could affect the performance of sodium acetate, and then your suspicion would make sense.
Namely, its purity/quality. On the Polish "Korex" forum I read information about the very poor quality of sodium acetate.
However, I use 99% pure sodium acetate from Hadron Scientific. This is fresh chemistry.
It's a good brand and I haven't heard of them ever having any quality issues.

I measured the acidity of the solution using a cheap (but not the cheapest) pH meter. It was around 5.4.
I've prepared this bath many times, and always using a freshly calibrated meter, I've obtained a pH between 5.2 and 5.4.

I believe the problem isn't with the mixing of the chemicals, but with the accuracy of the pH meter's readings.

I did not measure the pH of the solution before adding the acetic acid.

I ALWAYS use good-quality distilled water to mix all chemicals.
Unfortunately, the distilled/demineralized water available in Poland can sometimes be of poor quality.

Once again, I am not sure what caused the buffer to become unstable. Again, there are many variables.
But since then, I've been preparing this solution just before use.

 

[koraks]

OK, I see; I thought perhaps you were preparing the sodium acetate in situ by combining acetic acid and e.g. sodium hydroxide. This is the way I'd do it, but it would be fairly easy to end up at a slightly different pH. In your workflow this is unlikely to happen.

 

[Spektrum]

I prepare it exactly in the order I wrote here:

Sodium Sulfite clearing bath in ecn2 process

I have been using vision 3 film for about three years. I mix my own chemistry. Until recently I never used Na Sulfite as a clearing bath after the stop or bleach step. I didn’t see a sulfite clearing step in the protocols published by Kodak. But after reading some old posts that suggested...

www.photrio.com

 

[originalwinslow]

I admit it. I was the one who suggested this several times. Perhaps a few others did too.

Ok that's good my sanity, I thought maybe I had just imagined that.

I am going to mix fresh and run another test dev today to see if the separate clearing bath makes a difference. The outlier for me here continues to be the persistence of the fog even when omitting the ferri bleach and using blix instead.

 

[originalwinslow]

Btw, out of interest - have you been talking to Kodak proper, or to PSI? Kodak isn't the manufacturer in this case, after all.

I spoke directly with Photo Systems, the manufacturer of the chemicals

 

[koraks]

Thanks, that makes perfect sense.