Re-bleach cut C41 negatives?

[MattKing]

Is there anyone near to you that has their own, problem free bleach and fix that you could use to try re-bleaching your negs with.

 

[RPC]

if I switch to a ferricyanide bleach permanently, how would that change my process?

When using a ferricyanide bleach, it is absolutely required to use a stop bath, preferrably a clearing stop bath, followed by a wash, between the developer and bleach or the bleach will oxidize the developer and you will get a brown stain on your negatives. It is not necessary with Flexicolor bleach. You should also follow a ferricyanide bleach with a good long wash to prevent sulfurization of the fixer by the bleach, forming a fog on the film. I have used a ferricyanide bleach and it works well but as you can see it adds more steps and time to the process.

Looking at your film, I have doubts that the problem is under-bleaching. I have never seen film that is severely under-bleached, but I can't imagine the unexposed areas of the film being as dark as they are due to it, since little or no silver would form there. As someone else said, the problem lies elsewhere.

 

[clayne]

Edit: on second thought maybe it is actually something else.

 

[clayne]

Actually I took a second look at the negatives and I might have to agree with the previous poster somewhat. There are definite areas of clearness and if the CLS were uniformly there you'd get the brick factor going on.

When you get the pot-ferri run a few bleach tests on one of the strips. If you see no change then its definitely not a bleach issue.

 

[Rudeofus]

The processing manual (Z101, I believe) gives solution ratios. I do the math to mix up a 500mL batch, and I use it one-shot.

I just looked at that publication and didn't see any mixing instructions. I did find mixing instructions for replenisher which is way stronger than regular tank solution .... which would quickly explain your overdeveloped and foggy negatives.

Proper mixing instructions can be found here.

 

[keyofnight]

Is there anyone near to you that has their own, problem free bleach and fix that you could use to try re-bleaching your negs with.

Nope. I don't know anyone who can help. I did, however, just find the next best thing—the local photo lab said they would give me one of their test strips to run through my process. They'll run it through their densitometer and give me the control plots if I want. Pretty cool of them!

Looking at your film, I have doubts that the problem is under-bleaching. I have never seen film that is severely under-bleached, but I can't imagine the unexposed areas of the film being as dark as they are due to it, since little or no silver would form there. As someone else said, the problem lies elsewhere.

Definitely. At this point, I'm thinking it's the developer. What else can it be?

I'm finding a few people report that they've seen a really dark film base from over development, high heat, or too much agitation (there was a url link here which no longer exists) and it's also in a guide from FSU—the latter is one of the best things I've read on the subject. I called Kodak, and one of their techs also suspected overdevelopment. I'm thinking I'll double check my developer mixture, go easier on the agitation, and make sure my thermometer is calibrated.

I'll update when I learn more. Thanks, folks.

 

[keyofnight]

I just looked at that publication and didn't see any mixing instructions. I did find mixing instructions for replenisher which is way stronger than regular tank solution .... which would quickly explain your overdeveloped and foggy negatives.

Proper mixing instructions can be found here.

Hm! That would explain it, but I didn't see any mixing instructions in that document… it says to refer to the mixing instructions on the box. My box had no instructions. Hm. What can I do?

 

[Rudeofus]

Hm! That would explain it, but I didn't see any mixing instructions in that document… it says to refer to the mixing instructions on the box. My box had no instructions. Hm. What can I do?

The document I linked to states that the color developer bottles are meant to make 2l of developer soup. If the bottles contain some indication how much they contain individually, or if you can measure the content of these bottle somehow, then you should be able to mix less than the full amount at a time.

 

[keyofnight]

The document I linked to states that the color developer bottles are meant to make 2l of developer soup. If the bottles contain some indication how much they contain individually, or if you can measure the content of these bottle somehow, then you should be able to mix less than the full amount at a time.

Alright…I contacted Kodak about this, and they sent me the instructions on the label and said they would add it a new CIS document at some point in the future. (there was a url link here which no longer exists).

You were right: there is a _lot_ more of Part C in the replenisher mixture than in the tank solution mixture—now that I have both in front of me—and that would certainly cause the problems I've been seeing. Oy.

Thanks to everyone who helped sort things out. I truly appreciate it.

 

[MattKing]

Alright…I contacted Kodak about this, and they sent me the instructions on the label and said they would add it a new CIS document at some point in the future. (there was a url link here which no longer exists).

You were right: there is a _lot_ more of Part C in the replenisher mixture than in the tank solution mixture—now that I have both in front of me—and that would certainly cause the problems I've been seeing. Oy.

Thanks to everyone who helped sort things out. I truly appreciate it.

Thanks, but the linking process strips the attachment from the post you linked to.

Can you just link to the thread itself, and advise here what your post number is?

And attach the attachment here as well?

 

[keyofnight]

Sure! (there was a url link here which no longer exists)—post #94. I've also attached the document. Cheers, folks!

 

[clayne]

Glad to hear the chemicals are alright (albeit something missing from the mix) and the mystery seems to be solved?

 

[Rudeofus]

Sure! (there was a url link here which no longer exists)—post #94. I've also attached the document. Cheers, folks!

Watch out, these mixing instructions are for mixing 3 liters from the larger dev kit (which makes 8 times 3 liters), while the kit you use makes only 2 liters of working solution. Plan accordingly when you mix, or your developer will be too dilute this time.

 

[keyofnight]

Watch out, these mixing instructions are for mixing 3 liters from the larger dev kit (which makes 8 times 3 liters), while the kit you use makes only 2 liters of working solution. Plan accordingly when you mix, or your developer will be too dilute this time.

Right! I derive percentages from the amounts given in the instructions and use those to figure out how much of each component I need to make however much I need to make. I'll make sure to be extra careful this time, though…just so I know it'll turn out as well as possible.

 

[Mr Bill]

Hi, I hesitate to post after everything going on so far, and I being late to the game. But I think you're just spinning your wheels with all of the elaborate troubleshooting attempts.

This should be pretty simple to troubleshoot, and you don't need any control strips. Consider how the process works - where exposure occurred, the developer creates both a dye and a metallic silver image. The C41 bleach converts the silver image back to silver bromide, then the fixer dissolves all of the silver halide. All that should be left in the film is a dye image.

I just looked at your film comparison photo in post #10. Your processing has a very heavy "base stain," that is, the places where film should be "clear" are pretty dark. So it's either a developer or fixer problem. Why is this so? Ok, the edges of the film and gaps between frames don't have any exposure. So there should be no development here. No development means that there is no metallic silver. No metallic silver means there is NOTHING for the bleach to do. So any troubleshooting of bleach is a waste of time.

Here's what I would do, if I were in your darkroom. First, test the fixer. Do this by clipping off a piece of leader, then fix in the light to make sure it can "clear" the film. If it can, then you know the fixer is ok. Next, clip a piece of unexposed film (obviously in the dark) and develop by hand using the APPROXIMATE time and temperature. Rinse briefly in water, then fix. If this "clear" film is darker than the store-processed film, then it is due to the development step, and only the development step.

More than likely, you somehow botched the developer. I say this because fixer is pretty hard to mess up. About the only other possibility is that you are somehow fogging the film during development.

Your process is so far "out of whack" it's probably a waste of time to process that control strip.

ps: none of what I've said will test your bleach; you won't know anything about its condition. But some of the other posts tell you how to check it, AFTER you get your main problem fixed. By the way, I once described how the Kodak control strips check for a bleach problem, in this thread: (there was a url link here which no longer exists)

Good luck with the troubleshooting.

 

[RPC]

So, where do you stand now. Have you determined whether you used developer or replenisher, and whether it was mixed properly?

 

[keyofnight]

More than likely, you somehow botched the developer. I say this because fixer is pretty hard to mess up. About the only other possibility is that you are somehow fogging the film during development.

Yes—we just ascertained that later on in the thread. Foc, rudeofus, RPC, and clayne suspected that I may have overdeveloped them; and rudeofus noticed that I developed them in replenisher instead of tank solution. Flexicolor SM is nice in that it doesn't need starters, but Kodak never published ratios for mixing tank solutions, just replenishers. I just assumed they were the same for this particular chemistry. They are not the same.

You're right about the test strip. I won't bother with it until I develop negs that look like they're in the ballpark.

I just tested the fixer as you suggested, and the fixer is just fine.

So, where do you stand now. Have you determined whether you used developer or replenisher, and whether it was mixed properly?

Yes. I most certainly used replenisher instead of tank solution, and that caused overdevelopment. Now that I have the right instructions, I'm sure I'll get some measure of success next time.

 

[keyofnight]

Just to be on the safe side, I decided to create a spreadsheet to keep track of the mixture amounts. I noticed something: there is actually more of components B (hydroxylamine sulfate) and C (CD-4 and Sodium Bisulfite) in the tank solution than in the replenisher solution. This makes me a little nervous that my basic math is off or that my spreadsheet is wrong…but I know film chemistry is not always intuitive. Either way, it's clear that I was using the wrong mixture.

Could one of you take a look and see if I've made a mistake?

 

[Mr Bill]

Hi, on rereading the thread, I now see that the developer issue was raised several times, in particular by RPC who also pointed out that bleach shouldn't have to work on D-min areas.

Regarding your latest post, I don't see any calc errors. If anything is wrong, I'd guess it to be from the "label art."

Your results show that the Part B proportion used in TANK solution is much higher than in REPLEN. The most obvious explanation for this is that Part B contains restrainers (similar to byproducts from the film). This would also explain why SM chemicals don't need a "starter;" the key ingredients are already available by rebalancing the existing components (you increase the component containing the "starter chemicals").

As to why the mix, generally, doesn't seem right, my best guess is that the fresh tank solution was made empirically. That is, they tried to avoid having a separate "starter," so just found a best approximation by trial and error. (As a wild guess, the unexpected reduction of part C might be to try to keep the preservative package balanced, assuming the HAS was in part B.)

I have quite a lot of color neg processing experience, and have NEVER found a freshly made tank solution to match a seasoned mix. Generally they are somewhat close, but not good enough for critical matching work (anyone who knows what a VCNA or PVAC is, will know what I mean). The fresh processor solutions will always show shifts in the process control charts as they become seasoned. (In fact, different film mixes will shift the control chart plots to different positions.)

Anyway, I think there is a fairly good liklihood that Kodak came up with the final tank solution mix as a result of actual trials. But I would also be suspicious that the label art is not correct.

If I were in your shoes, I'd just mix per your calculations, and run the control strip for a "reality check" (I'd be pretty surprised if everything was within "spec limits). If you don't know what everything means on the control strip, an actual film test is probably more useful.

 

[keyofnight]

Your results show that the Part B proportion used in TANK solution is much higher than in REPLEN. The most obvious explanation for this is that Part B contains restrainers (similar to byproducts from the film). This would also explain why SM chemicals don't need a "starter;" the key ingredients are already available by rebalancing the existing components (you increase the component containing the "starter chemicals").

Excellent. That was my hunch given what I could Google about hydroxylamine sulfate. Thanks for corroborating—it makes me feel a lot better.

I have quite a lot of color neg processing experience, and have NEVER found a freshly made tank solution to match a seasoned mix. Generally they are somewhat close, but not good enough for critical matching work (anyone who knows what a VCNA or PVAC is, will know what I mean). The fresh processor solutions will always show shifts in the process control charts as they become seasoned. (In fact, different film mixes will shift the control chart plots to different positions.)

I see! I read about this in the Z101 publication, but they don't say much about how long it takes for a working solution to become well-seasoned. How long does it take?

If I were in your shoes, I'd just mix per your calculations, and run the control strip for a "reality check" (I'd be pretty surprised if everything was within "spec limits). If you don't know what everything means on the control strip, an actual film test is probably more useful.

Okay! Cool. I'll develop another test roll of cheap film. If it comes out looking somewhere in the ballpark of normal, then I'll run a test strip just for kicks. I don't know what control strips mean, but it's about time I learned.

 

[Mr Bill]

Hi, the "starter chemicals" are most likely bromide ion and a tiny bit of iodide ion (from NaBr or KI), among other things. They may not show up on MSD sheets because of the low concentrations. I'm just guessing that they're in Part B to explain the otherwise odd mix ratio.

Hydroxylamine sulfate (HAS) is generally considered to be part of a preservative package. It seems desirable to have it in some sort of balance with other preservatives; this is the basis of my wild guess as to why the Part C is also reduced somewhat (the assumption is that other preservative components are in Part C). I don't know the mechanisms, or have any real basis for saying this, though (at least that I recall); it's more of a hunch, or perhaps better said, a "wild guess."

Regarding "seasoning," a general rule of thumb is that two tank-turnovers is pretty near being fully seasoned. So if you had a 1-gal processing tank, this would mean running 2 gallons of replenisher through it. It takes longer than you might think, but unless you're really trying to keep your control plots screwed down tight, who cares? If you were to set up for high output, almost like a factory production line, then it would be important, but otherwise, maybe not.

Learning to interpret problems via control strips can be almost an art, and can be much more complicated than learning how to mix chemicals and develop film. There are example charts in the Z manuals, but I never found them to be too useful past a rudimentary level. If you trust them explicitly, you might, for example, have an over-replenished system (too much developer activity) but finding a match to a Z-manual example chart might imply that your temperature is too high, or that your mix was too concentrated. You have to be careful not to read in more precision than is really there.

If you want to understand what the control strips are actually showing, a good way to start is to study "characteristic curves" of film a bit. Then imagine the control chart as showing a couple of exposure points on those curves.

 

[Rudeofus]

Mr. Bill, all these starter chemicals and seasoning efforts are meaningless here because keyofnight uses a kit that doesn't have or need these things. He uses a kit that you mix according to (poorly written) instructions, then use for a dozen rolls or so, then discard. Since there is no continuous operation, and temperature control if flaky at best with hand inversion tanks, control strips are mostly pointless.

The problems, that keyofnight reported, were most likely resolved around August 1st, and with correctly mixed components keyofnight will likely get very nice and printable negatives like most other users of C41 home dev kits including myself.

 

[RPC]

No need to worry about fresh working solution (properly mixed), exactly matching a seasoned tank. They both should meet Kodak specs if a control strip is run, and that's what's important.

 

[Mr Bill]

Hi Rudeofus. Point taken; I have been meandering.

However... I started out to answer post #43, where keyofnight, in his pdf file, noticed a discrepancy. The TANK solution is essentially MORE CONCENTRATED than the REPLEN. I figure this cannot possibly be a "correct" formulation.

I made some guesses as to how this might work, but later looked through some MSD sheets for SM chemicals, and found that my guesses don't work either - the restrainer is in the only part, A, that uses the same amount for both. There is more wrong, but I'll spare you that.

Since Rudi indicates things are likely solved, but I don't see it, I went back through the entire thread, following the links, etc. About the only thing I come up with is that keyofnight uses a Kodak part# that, per the Z-manual, is specified as a "tank" version. Even though it is called C41 SM, just like the replenisher versions. So my best guess now is that the "tank" version is formulated differently and that there is no point comparing the "tank" vs "replen" mix ratios because they're two different animals sharing the same name. (Wish they would have named it differently, though; SM is supposed to be the plug-n-play machine version where the operator never comes into contact with the chemicals.)

Anyway, I really don't know if the problem is solved or not. I wouldn't trust it without a confirmation test.

 

[Rudeofus]

However... I started out to answer post #43, where keyofnight, in his pdf file, noticed a discrepancy. The TANK solution is essentially MORE CONCENTRATED than the REPLEN. I figure this cannot possibly be a "correct" formulation.

Looking through the MSDS and comparing what I see in these with the MSDS of these tank solutions, I could not see Iodide anywhere in the MSDS although it is most likely part of any correct C-41 formula. Given that MSDS don't have to list ingredients that are contained in low concentration, there is a very high chance that the Iodide is contained in one of these parts but simply not listed. We also know that Iodide will readily oxidize to Iodate unless protected by some other compound, and I would expect that HAS does this job in part B.

All this indicates that part B likely contains Iodide which is a much stronger restrainer than Bromide, and if you add too little of part B you will get fog and other issues.

And yes, as you stated, a confirmation from keyofnight would be nice, but given that these dev kits generally work well I am quite confident that his next negs will come out fine.