E6 processing error?

[willfrancis]

Hello all (I’m new here, so please be gentle...),

I recently decided to try and home process several rolls of (new) E100 that I’d shot over the summer, due to the exorbitant processing costs where I live. Being more intrepid than I am sensible, I set out to mix my own solutions rather than buy a kit. I followed Stefan’s ‘updated’ formulas for the FD and CD, along with his processing times, to the letter. For the reversal, I opted to go with a light reversal, using a 60w incandescent equivalent LED bulb to expose each side of the water-submerged reels for approx. 3 mins in a white bowl. I used an EDTA bleach and prebleach based on the Fuji formulae, and then a two stage NH3 thiosulphate fix followed by a formalin stabiliser.

Unfortunately, upon running a development for the first time, my two test films came out of the final bath very dark and almost opaque. Individual frames were just about distinguishable (as negatives) when peered at under strong light, but something had clearly gone quite wrong.

I then set out to work out what that something might have been, first re-bleaching/fixing part of one of the original rolls to see if the error was an insufficiency of either bath (there was no difference); assuming that everything after the CD was working as it should, I then substituted the FD for HC-110 B for 6 mins with a test strip. At the light reversal stage, I was pleased to see that the HC-100 developed negatives were significantly clearer than those at the equivalent stage after developing in my brewed FD, seemingly confirming my suspicions that the error was in my mixing of the FD. However, at the end of the process, despite the negatives’ earlier clarity, I found that they again emerged a dark-ish brown, with faint traces of the negative frames (see the attached images) - but certainly no colour, nor proper transparency of the emulsion. I’m thus feeling slightly stuck - there seems to be something wrong with both the FD and the CD, which is frustrating as I’d taken pains to be meticulous in mixing up all the solutions...

Has anybody else faced a similar problem before? Has anybody got some sort of idea what may have gone wrong? I did wonder whether I may have been colossally stupid and done something like labelling the two developers the wrong way round, but I don’t believe that I did... for reference, the appearance of the FD is pale yellow which turns a faint-ish pink when poured back into its bottle, slowly returning to the original colour with time. The CD has a similar original colour if slightly darker, but turns a deep, intense purple somewhat reminiscent of grape juice in the development tank. Again, after being returned to its bottle the colour fades and it regains a pale yellow hue.

Apologies for the essay - I just wanted to give as much detail as possible! Thanks very much.

 

[Anon Ymous]

Hello Will

I have a suspicion that there's not a single problem in your process, but possibly more than one. The FD seems to work reasonably well, at least it shows signs of life that is... You get a negative image, so I guess it works. So, you wash your film, expose it under a lamp, then proceed to the CD. Now, here's the first weird thing, you should have a colour image, even if it's a very low saturation one if there's a lot of metallic silver left. Quite frankly, I don't know if your CD works at all judging from the attached photos. Then, your bleach probably failed as well. There seems to be far too much metallic silver left on the film, something that fixer can't remove. Obviously, I can't comment on the quality of your fixer at this point and with so many unknowns...

Since you're into home brewing, you may already have potassium ferricyanide. If you do, try mixing a rehalogenating bleach with potassium bromide. While E6 film might not be rated for such a bleach, it will certainly work and reveal any bleaching problems. After you've bleached your film, give it a good wash and then fix it. It would be interesting to see what it looks after this stage, but I suspect that we're not going to see much of a colour image, if at all considering what you've showed us. For the record, the colour of your solutions is ok and that's what I'd expect from my experience.

By the way, before committing any precious film you've already shot, it would be a good idea to make tests with short film clips. Processing a clip that half of it has been fully exposed (film leader), while another part hasn't should give you something that half of it is clear, while the other half is black, but with frame numbers etc on it. This alone could tell you if your process works reasonably well.

Anyway, keep us informed, good luck and don't give up!

 

[willfrancis]

Hi,

Thanks very much for your thoughts - I’m very grateful for your taking the time to make suggestions, and of course for the moral support!

Yes, I think I’ll try it all again but substituting a ferricyanide bleach - I had wanted to avoid this as I’d read there can be problems with staining (although currently that’s sadly become the least of my concerns!) - at least it may give a clearer idea of how other things are working. For the record re: fixer, I’d mixed a fresh pair of 1l baths with 80g ammonium thiosulphate and 5g of both Na sulphite and bisulphite per litre - fixing time in each bath was 4 mins. I tested a b/w film leader for clearing time to check fixer activity, and it cleared within a minute. The Fe (iii) ammonium edta that I’d used for my bleach came from Suvatlar in the form of a 50% soln, of which I added 240ml. I wonder whether in both cases my quantities are off?

Perhaps if there is a problem with the bleach, it lies in my use of mercaptotriazol in the pre-bleach - I had read that it was necessary as a accelerator but can in fact slow things down considerably if present in too large a quantity (I used 0.4g, the amount of thioglycerol which I was replacing - should I have added less?).

I did wonder whether I just need to increase the dev (and indeed other) bath times significantly; it would just seem slightly odd as the formulae I’d copied seemed pretty clear! I’m comfortable that my temperature control and timing are not the issue here (famous last words). I’m agitating twice every 30s; perhaps I need to increase this...

Anyway, thanks again.

 

[Anon Ymous]

To be clear, I suggested using a ferricyanide bleach to film that you have already processed, at least few frames of it. This will give clues about what has already gone wrong. I believe your fixer is fine, even if it is a tad slower than the commercial E6/C41 fixer. I also suspect that mercaptotriazole concentration in pre-bleach isn't that much of an issue. High concentration in bleach may be, but not in pre-bleach. User @Rudeofus has done some tests in the past and knows some details, he will probably see this post and respond. Also keep in mind that some cary-over of prebleach to the bleaching stage is required, I hope you're not washing between these two stages. But even so, even without using any pre-bleach, you should have a mostly bleached result, with somewhat high and brownish Dmin if things didn't go that well. And yes, I've had this problem in the past...

Don't alter the development times, these should be ok. Bleaching times may need to be increased though, or repeat the bleach - fix cycle. Oh, one other thing that you can do is try to develop a film clip in E6 CD. It should produce reasonably high density. Obviously, you can try it in full light in a small graduate with BW film, no need to waste slide film. Develop at 38°C though, it probably is too slow at 20...

 

[willfrancis]

Ah, I see - thanks for clarifying. I will actually need to order in some ferricyanide, but as soon as I have some results there I’ll post them.

As for the pre-bleach and carryover, I don’t carry out any wash step between either the CD and the pre-bleach or indeed the pre-bleach and the bleach.

I’ll try some tri-x in a little CD and see what happens...

 

[Rudeofus]

A critical part in Ammonium Ferric EDTA based bleaches is pH. It must be somewhat acidic to become active. Ideally your bleach pH would be between 4.5 and 5.5. You can't go much lower, because EDTA free acid would precipitate, and at higher pH the bleach becomes too weak.

The 0.4g Mercaptotriazole look fine to me, as long as they are in the prebleach. There will be some carryover of Mercaptotriazole into the bleach, which is fine, but bleach must not contain much more than 0.1 g/l Mercaptotriazole.

One more thing: E6 FD has to be foggy and high in contrast in order to give good slides. To give you an example: if you develop Tri-X in E-6 FD at 20°C, it would be developed to normal contrast in about one minute! Too much fog will give you slides with weak shadows, but some fog is definitely ok.

 

[willfrancis]

Thanks - I need to find a new pH meter as the one I was using proved unreliable, and I foolishly thought I could do without if I stuck to the formula religiously! If I were to try and adjust the EDTA bleach pH to make it more acidic, would it be completely necessary to use nitric acid as specified in the Fuji formula? I have acetic, citric and sulphuric acids but not the nitric. Is there a risk of unwanted compound formation with one of these?

 

[Anon Ymous]

I'd use acetic acid.

 

[willfrancis]

Noted, thank you.

 

[Rudeofus]

Most commercial bleaches use Nitric Acid or alkali nitrates in order to prevent corrosion of stainless steel. Unless you have stainless steel tanks and keep the bleach in there for days, there is no need to handle Nitric Acid or alkali nitrates.

 

[Rudeofus]

Until that pH meter arrives, you can try the fizzle test I described in my article.

 

[willfrancis]

@Rudeofus, thanks for the clarification re: nitric acid. That makes a lot of sense! I’ll have a look around for your article on the fizzle test!

Will let you all know how I get on playing around with the pH - hopefully that will help provide some answers in the FD and CD too...

 

[Rudeofus]

Sorry, I assumed you got the info about Mercaptotriazole from my article anyway. The "fizzle test", as I call it, is described in section 4.2 here. It's a very simple procedure for making sure, that your bleach is sufficiently acidic to be effective.

 

[willfrancis]

Right, tried the fizzle test - added 13.3ml 60% acetic acid to no observable result; another (identical) dose resulted in weak fizzing which perked up when the beaker was swirled a little; a final addition of 7ml of the acid resulted in almost immediate and sustained fizzing. My initial mix must have been way off, pH-wise! That’s quite a lot of acid to have had to add to buffer it...

Thank you very much for the suggestion, it’s been really helpful. Tomorrow I’ll rebleach a couple of strips from one of the original rolls in a fresh ferricyanide bleach and also the now-buffered EDTA and will post results for comparison. Hopefully, this will solve the bleach problem, although I still need to figure out what the issue with the CD might be.

 

[Rudeofus]

The compound causing these weird color shifts in E-6 CD is most likely Citrazinic Acid, one of its ingredients. There is a completely useless English language wikipedia entry for Citrazinic Acid, but the Russian language version describes these color shifts in aqueous solution as characteristic reaction of Citrazinic Acid.

So far we have no reason to assume, that your E-6 FD or E-6 CD was bad.

 

[willfrancis]

Hi there! Sorry it’s taken me a couple of days to post.

So, it turned out that the error was indeed just in the bleach. Having adjusted the pH for the fizzle test, I used my new pH meter to double check it and it still came out a little high, at about 5.7. I brought it down to 5.3 with some more acetic acid to ensure it was well within activity parameters for the EDTA. I then rebleached/fixed the film I’d souped initially and was delighted to see that it came out looking very much as it should, with colours seemingly all in the right places!

Just to be sure, I checked the pH of both the FD and the CD; the former came out to 9.66, which for the sake of absolute precision I adjusted to 9.64 with some H2SO4 added dropwise. The CD was slightly low, measuring 11.71, which I brought up to 11.96 with NaOH (although looking at the re-bleached initial results, it didn’t seem that the low pH had caused any severe problems, if any at all). A final double-check with a short strip of test film confirmed that all was working as it should, so yesterday I committed two of my ‘real’ rolls to the development tank and (phew) they emerged wonderfully!

I’m very grateful for your help in pointing me in the right direction, diagnostically speaking - lesson learned, in future I’ll always make sure to buffer my bleach properly in advance! If I were to reuse said bleach, how often (in number of rolls) should it be replenished with ammonium bromide? As for oxygenating the beach, is it sufficient to place it in a large beaker with magnetic stirring for an hour or so? Again, how often should one do this to maintain activity? Thanks!

 

[Anon Ymous]

Nice to see that you made it. To be honest, judging by the shots at the OP, I wasn't sure that you had any colour at all, I couldn't see any.

The difference in FD pH is negligible and probably within the tolerance of your pH meter and the process itself. Obviously, nothing wrong with correcting it. The FD pH is a bit on the low side, but not too far off. This will shift colour balance a bit to the green, while higher pH values would shift it towards magenta. Such shifts are easier spotted if you shot something like a colour checker card in daylight, you'd have a good point of reference this way.

Now, in order to have an estimate of the bleach capacity, have a look at Tetenal's instructions. Yours should have comparable capacity. Keep in mind though that adding ammonium bromide will extend capacity, but you also need to adjust pH as well, it slowly rises after each use. I don't know how good a magnetic stirrer is for oxygenating bleach, perhaps an aquarium pump would be cheap and effective. To be honest, I just shake my bleach bottle for few minutes well before each use. I store mine in a half empty bottle for this reason, makes aeration easier. Oh and every once in a while you'll need to filter it. Some kind of gelatinous gunk is accumulated.