C-41 is blowing my top....

Jacko1729 · Dec 7, 2008

Hello all,

I've only just started processing my C-41 stuff with the advent of the new Ektar, and everything is going great with one huge exception.....a few seconds after I start the Blix cycle, it will blow the top off of my tank. I'm using my Jobo CPE2 processor and two roll tank.

I'm using the Unicolor C-41 kit from Freestyle. On their instruction sheet for Automatic Rotary Tube Type Temperature Controlled Processors, you go directly from Developer to Blix (Step 2 and 3). Now, in my Jobo book, it says "Regardless of the chemical manufacturer's instructions, JOBO suggests that a 1 minute stop bath of 1 to 2% Acetic Acid be used to prevent any carry forward of developer into the bleach."

I'm assuming a chemical reaction here, and I've tried three different ways....

1)I used a stop bath after developer, but I think I mixed it wrong, and it blew the top off (poof) and rather violently. I quickly replaced it, and it promptly blew it off again.
2)I used a 'quick' wash after development, and it blew the top off, but just not as quickly or violently.
3)Used Unicolor's instructions, and it blew the top off, but only once, and not violently.

In all three episodes, I've recovered somehow and continued processing and still managed to get great negatives. However, I don't think it should be blowing the top off my tank (the soft plastic cover over the fill hole).

I am a novice with C-41, so any help is appreciated! I've never blown anything up with my E-6 stuff

Thanks,

Jack

Photo Engineer · Dec 7, 2008

Jack;

C-41 using Kodak chemistry was designed with a carbonate developer and a neutral bleach. Therefore, use of an acid bath after the developer can cause generation of a lot of Carbon Dioxide gas. Don't do it! Go from the developer into the bleach bath directly with good, continuous agitation.

PE

MikeSeb · Dec 7, 2008

Are you using nitrate-base film?

I've used the very C41 kit you refer to--as well as a variety of 3-bath processes--and all of them in a Jobo, and I never had that happen. Never used stop bath either--just filled the three numbered bottles with dev, bleach/blix, fixer, and went to town.

Where's Photo Engineer when you need him? I think he must have a real life unlike us!

Wait...look! Up in the sky over Rochester....it's a bird...it's a plane...it's PHOTO ENGINEEEEEER!!

Oh, PE beat me to the punch!!

rusty_tripod · Dec 7, 2008

My Tetenal kit says to vent the lid after putting the blix because it generates gas. Sounds right! After I put in the blix, I leave the sealing cap off.

Photo Engineer · Dec 7, 2008

The Jobo processor actually has a vent system built into it for just this reason. But a lot of gas can be generated.

Mike, thanks, but I cannot fly. And I sure do look wierd in tights with a cape. I quit wearing them. BTW, if I could fly, do you think I would be here in Rochester?

PE

pentaxuser · Dec 7, 2008

I always had a problem with "blowing" after putting acid stop bath in the Jobo tank. There seemed to be two solutions. Try and vent the top after a few seconds( usually worked but not always) or, I think, better still, just use a simple inversion when on the stop bath cycle and then go back to rotary processing on the blix stage

pentaxuser

2F/2F · Dec 7, 2008

Interesting instructions from Jobo. I always rinse off the developer with water until the water appears clear, then go into the bleach.

I found out that Jobo's pre-soak instructions are to be followed however, after listening to some Photo.net supposed expert's advice not to pre-soak and ending up with horribly streaked film.

markbarendt · Dec 7, 2008

Okay,

Sounds exciting so far.

So, before order my first batch of C41 chemicals and blow the lid off my little stainless tank and get banned from the kitchen forever let me ask this.

Does using separate bleach and fix steps, instead of a combined single blix step, solve the issue?

markbarendt · Dec 7, 2008

2F/2F

So you just add a rinse step, do you get any bubbles that threaten to blow the lid off?

Also what chemical set and steps do you use?

Presoak
Develop
Rinse
Bleach
Fix
Stabalize
Dry

Photo Engineer · Dec 7, 2008

The process that I posted here for C-41 is

Presoak
Develop
Bleach
Wash
Fix
Wash
Stabilze
Dry

Use of a wash at 100F for C41 after the developer will cause overdevelopment of the cyan layer on the bottom and will thereby lead to some crossover and color balance shifts. It is not recommended by Kodak. A stop is allowed.

PE

2F/2F · Dec 7, 2008

markbarendt said:
2F/2F

So you just add a rinse step, do you get any bubbles that threaten to blow the lid off?

Also what chemical set and steps do you use?

Presoak
Develop
Rinse
Bleach
Fix
Stabalize
Dry

I use the Kodak 1 gal. kit. I have over a dozen kits that expired 10 years ago and were given to me by a lab/gallery that went 100% black and white, and I have been working my way through them. I do exactly what you wrote, but I wash after the bleach and after the fixer, which is part of the C-41 process.

One note is that the stabilizer is now called Final Rinse, and it is actually different, not just a name change. I use the old Stabilizer that came with the expired stuff, but have heard that one should not use Final Rinse with "older" films. (Please tell me I don't have that backwards...) What "older" means I do not exactly know, however.

I get no crazy bubbles, lids blowing off, or color shifts, and certainly no color crossovers. Maybe it is just dumb luck. Or maybe the old chemicals are shifting the film the other way, compensating for the overdevelopment of the cyan layer.

markbarendt · Dec 7, 2008

Thanks PE and 2F/2F

Photo Engineer · Dec 7, 2008

Old and new developer, bleach and fix do not cause problems. Using old stabilzer works with all films, but using new stabilzer will allow older films to fade due to a different family of coupler being used in the old vs new films. The old ones used formalin for stability.

Formalin is a bacteriostat / fungicide as well and the new films use a rather benign version of a bacteriostat / fungicide.

As for crossover, I have been able to measure it, but what the heck, if it works for you to your satisfaction use a rinse after development. It is even worse with color paper!

PE

2F/2F · Dec 7, 2008

Photo Engineer said:
Old and new developer, bleach and fix do not cause problems. Using old stabilzer works with all films, but using new stabilzer will allow older films to fade due to a different family of coupler being used in the old vs new films. The old ones used formalin for stability.

Formalin is a bacteriostat / fungicide as well and the new films use a rather benign version of a bacteriostat / fungicide.

As for crossover, I have been able to measure it, but what the heck, if it works for you to your satisfaction use a rinse after development. It is even worse with color paper!

PE

Well, with what you have written, I will no longer rinse after development. I started doing it to cut down on contamination of the bleach, and all I have noticed is that my bleach takes a lot longer to turn dark. I am still interested in knowing when the couplers changed (what exact films, what years, etc.), so I know what films are not safe to use with the newer Final Rinse.

Photo Engineer · Dec 7, 2008

I really don't know when they changed. I believe that it was about 2000, but that is just a guess. Sorry. And, BTW, they have not changed in E6. That process still uses formalin, but as the bisulfite adduct in the pre-bleach bath.

The color change in the bleach is due to formation of oxidation products of color developer carried over. A drop or two of sulfite solution will clear that up just to demonstrate it to you. It will harm the bleach as well, so this is not a cure, just a demo.

Color developer, in any acidic solution such as stop or bleach forms a pink color that slowly turns brown. A pinch of sulfite will decolorize it. This is a quick test for p-phenylene developers.

PE

Jacko1729 · Dec 7, 2008

Thanks everyone for your responses. I think what I will do is vent the tank during blix, at least for the first minute or so. Both times it has happend it scared the crap out of me, mainly because I didn't know what happened. All it did was dump blix into the bath water, but I don't need that happening either.

Jack

wogster · Dec 7, 2008

Photo Engineer said:
The process that I posted here for C-41 is

Presoak
Develop
Bleach
Wash
Fix
Wash
Stabilze
Dry

Use of a wash at 100F for C41 after the developer will cause overdevelopment of the cyan layer on the bottom and will thereby lead to some crossover and color balance shifts. It is not recommended by Kodak. A stop is allowed.

PE

I would think the chemistry manufacturer would know best how their chemistry should be used. The tank manufacturers instructions could come from 30 years ago, when it might have been a requirement to do it that way. One should always read and follow the instructions from the kit manufacturer.

Photo Engineer · Dec 7, 2008

Paul;

The C-41 data sheet has been posted here on APUG by me. It gives details.

PE

wogster · Dec 7, 2008

Photo Engineer said:
Paul;

The C-41 data sheet has been posted here on APUG by me. It gives details.

PE

Like I said, if one is using a Kodak kit, then they should use Kodak's directions, rather then the tank makers instructions. Tank makers have generic instructions, without regard to the possible differences between chemistries from different manufacturers, The tank maker is also unlikely to update their instructions very often. If Kodak, for example, felt that a stop bath between development and bleach, was a good idea or required, they would have included it, at least as an option.

mtjade2007 · Dec 7, 2008

All Kodak Portra line of films should use the new final rinse. The older VPS (including VPS-III) should use older stabilizer. I have a bunch of expired VPS-III that I like a lot. But I can no longer find old stabilizer. What should I do about it? What I do now is to scan the films immediately after processing. The problem is my film scanner is not up to the task to archive them in a high enough resolution. Another question is how about Japanese C-41 films? Should I use the new final rinse or the old stabilizer? I am sure a lot of labs down the street do not stabilize your films with a correct final rinse or stabilizer. You will not know until it is too late.

I never pre-soak my films and I never get any streaks on my negs. The problem with pre-soak is it tends to dilute the developer, especially if you use a minimum amount of it required for the film you are developing.

I made a lot of mistakes in C-41 process using my Jobo in the past. I think I have learned to process perfectly now. The result is wonderful. I fall in love with all Kodak negative films, old and new, again. Havn't tried the new Ektar 100 yet. I am sure it will be a joy to develop, scan and print it.

Photo Engineer · Dec 7, 2008

The purpose of the prewet is mainly to temper the reels, the tanks and the film. Dilution is miniscule if you drain properly. I have done this for over 20 years with no problem.

PE

2F/2F · Dec 7, 2008

mtjade2007 said:
All Kodak Portra line of films should use the new final rinse. The older VPS (including VPS-III) should use older stabilizer. I have a bunch of expired VPS-III that I like a lot. But I can no longer find old stabilizer. What should I do about it? What I do now is to scan the films immediately after processing. The problem is my film scanner is not up to the task to archive them in a high enough resolution. Another question is how about Japanese C-41 films? Should I use the new final rinse or the old stabilizer? I am sure a lot of labs down the street do not stabilize your films with a correct final rinse or stabilizer. You will not know until it is too late.

I never pre-soak my films and I never get any streaks on my negs. The problem with pre-soak is it tends to dilute the developer, especially if you use a minimum amount of it required for the film you are developing.

I made a lot of mistakes in C-41 process using my Jobo in the past. I think I have learned to process perfectly now. The result is wonderful. I fall in love with all Kodak negative films, old and new, again. Havn't tried the new Ektar 100 yet. I am sure it will be a joy to develop, scan and print it.

How much VPS III do you have? Or, rather, over what period of time will you be processing it. I would be willing to trade you some of my old Stabilizer for...? Film, paper, perhaps? Problem is that it lasts for only eight weeks once mixed.

Jacko1729 · Dec 8, 2008

wogster said:
Like I said, if one is using a Kodak kit, then they should use Kodak's directions, rather then the tank makers instructions. Tank makers have generic instructions, without regard to the possible differences between chemistries from different manufacturers, The tank maker is also unlikely to update their instructions very often. If Kodak, for example, felt that a stop bath between development and bleach, was a good idea or required, they would have included it, at least as an option.

I agree, but when a novice like me reads "Regardless of the chemical manufacturer's instructions" in one set of instructions, and the chemical manufacturer says absolutely nothing about needing to vent the tank during blix........ it's easy to be confused.

but then again I wasn't using Kodak chemicals, which may have more explicit intructions.

Jack

wogster · Dec 8, 2008

Jacko1729 said:
I agree, but when a novice like me reads "Regardless of the chemical manufacturer's instructions" in one set of instructions, and the chemical manufacturer says absolutely nothing about needing to vent the tank during blix........ it's easy to be confused.

but then again I wasn't using Kodak chemicals, which may have more explicit intructions.

Jack

If venting the tank works..... The real issue is that the tank manufacturer should not be taking control over a process like that, because what was useful at one time, may not be any longer. The chemical manufacturers are continually working to make their products less toxic both in use and in manufacture. This could result in the use of materials that a few years ago wouldn't have had problem with this, to now have a problem.

Photo Engineer · Dec 8, 2008

Jack;

What was your stop bath? That might have a bearing on this. After draining, adding a 1% acetic acid stop should not be too bad. It will fizz, but after thinking about it, if it were too strong, or the drain was not sufficient, there would be a lot of fizz.

PE

C-41 is blowing my top....

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