Is this replenishment scheme going to cause excess development strength?

brbo said:

No. It can't. Self-replenishnment from working solution can't ever (even theoretically) cause excess developer strength.

It can't even bring the strength of your replenished working solution to the strength of the original working solution. Unless you are doing 100% replenishment (before somebody asks, yes, 99.95% would be fine as well), of course.

But, you are probably more concerned whether you are replenishing more than you should. The answer again is no. So, what you really are asking is whether you are "replenishing" more than what manufacturer thinks is an acceptable drift from proper developer strength for a home user where they can blame the user and not their false advertising for less than optimal results. To which, obviously, there is not a definitive answer.

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The excess development strength concern came from two beliefs I held:

1. That replenishment was always done to with working strength solution.

2. That the developer included in the kit was the same flexicolor develeoper replenisher that requires being aged with a starter or it can be too strong at regular fresh working strength.

I am still not totally clear about what the correct answer to number 1 is. With commercial volume combination developer replenisher solutions, how does the replenisher mix ratio actually compare to the starting working strength ratio?

hwy17 said:

With commercial volume combination developer replenisher solutions, how does the replenisher mix ratio actually compare to the starting working strength ratio?

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For e.g. Fuji, you could find numbers like these:


Look at the bottom row of the table where it says "TANK from REP". This means "mixing a working strength developer as used in a tank or machine from an already mixed replenisher". As you can see, they take 850ml of replenisher, add 135ml of water and 15ml of starter. The starter is a solution of mostly sodium bromide in water. So you can take from this that a regular working strength developer is the replenisher watered down by around 20% and has some bromide added to it. You can easily conclude from this that the working strength developer is significantly less active (it's more dilute and the bromide further restrains it) than the replenisher.

Hope this finally clears it up.

koraks said:

For e.g. Fuji, you could find numbers like these:

View attachment 401306
Look at the bottom row of the table where it says "TANK from REP". This means "mixing a working strength developer as used in a tank or machine from an already mixed replenisher". As you can see, they take 850ml of replenisher, add 135ml of water and 15ml of starter. The starter is a solution of mostly sodium bromide in water. So you can take from this that a regular working strength developer is the replenisher watered down by around 20% and has some bromide added to it. You can easily conclude from this that the working strength developer is significantly less active (it's more dilute and the bromide further restrains it) than the replenisher.

Hope this finally clears it up.

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Yes that's perfect thank you.

If the product when purchased is already at the intended working activity level, rather than at the higher activity level of the more traditional replenishers, then using it to develop a roll of film will decrease its activity by a small amount. When you discard some of that used developer and then top the volume up to its original volume with developer at the initial activity level, the activity level of the resulting mixture will be slightly less than the original.
As you use the working strength mixture, its activity level will slowly decrease over time.
The progression (regression?) of the activity level change depends on how much film is developed, and how much developer is discarded and replaced ("replenished") for each roll of film.
Increase the replenishment rate, and you will slow the progression.
You may be content with the progression - i.e. your requirements may be well satisfied with any film that you develop over the entire life of a kit, despite the variability you encounter. Others might require less variability.
If I was paying someone to develop my film, I would require them to objectively confirm that the variability that results from proceeding this way was within acceptable small tolerances - using sensitometry (control strips and densitometer plots).
If I was doing this for myself, I'd probably be willing to gauge the results more informally, based on results, but I'm cognizant of the risks.
Without the objective data from more formal sensitometry, I'm not sure I would recommend continuing replenishment of an existing used working strength volume after a kit is finished and with the contents of a new kit. To be safer, it may make more sense to discard and start anew. It may be though that the progression would permit using one or more additional kits before the results become less acceptable to the user - perhaps with an ever increasing replenishment rate.

MattKing said:

I'm not sure I would recommend continuing replenishment of an existing used working strength volume after a kit is finished and with the contents of a new kit. To be safer, it may make more sense to discard and start anew.

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To be clear about that part of the plan. I'm planning to discard all of the first kit after use. When I get to the second 5L kit I may consider mixing 1L of starter from it and using the remaining 4L as a replenisher.

In my use once and dispose plan (500ml/4x135) I would get 40 rolls per 5L kit. If I follow Cinestill's 40ml replenishment advice, then I could get up to 100 rolls per kit.

Most likely I will find that the pace of my own demand will make this question moot, as I'm not interested in keeping any chemistry around for longer than 6 months and I'm unlikely to be consuming more than 40 rolls in six months. But I learned something about how commercial developer and replenisher solutions compare at least for the Fuji chemistry and that's what I was looking for.

Thanks all

Thanks for the extensive reply,originalwinslow. It was your first method and only this method of re-using the litre and extending times that excited my interest. I did wonder if something like adding 5% every 5 rolls was your way of avoiding a lot of calculatíons and decimal points but when I am unsure of answers I like to ask questions rather than make assumptions

This method results in your getting 30 rolls per litre so 6 more than Cinestill suggests which is great

The picture you showed of the bush and cars looked pretty good to me so can I clarify: Was that one from the above re-use method or from the replenishment method? If the latter can I take it that all negs processed from the re-use method were equally as good?

When I make prints these will all be from optical enlarger and RA4 paper. I do not scan like you so I realise that it is difficult for you to say that under an enlarger the same print as you showed would have been possible but can I ask :

Was there a point after a set number of batches of 5 films that the negs were noticeably different such that changes had to be made to the scanning? If so what were those changes?

I'l be honest and say it is likely that l will be unable to say if those changes in scanning will translate into possible or impossible changes on an enlarger but those with both skills here on Photrio might be able to

Yes the simple answer is that I have to find out for myself at what point in the 5 film batch cycle my negs change to a "point of no return" where I cannot get acceptable results under an enlarger but the whole point of a forum is that the collective knowledge available might help

Thanks

pentaxuser

pentaxuser said:

The picture you showed of the bush and cars looked pretty good to me so can I clarify: Was that one from the above re-use method or from the replenishment method? If the latter can I take it that all negs processed from the re-use method were equally as good?


pentaxuser

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The image I attached was specifically after using the rudimentary replenishment method I mentioned, but in both cases I am adding additional time. 1500ml of developer used for 30 rolls at 1% additional time per roll then replacement of 500ml old developer with fresh original working solution. As others have pointed out, this should definitely not be a sufficient replenishment to get the developer back to its original strength, and that makes sense. However, I returned to original 3:30 dev time after this "insufficient" replenishment and got good results to my eye. Perhaps it was a fluke, or perhaps I am not seeing the errors. I am not lab-testing density, purely an unscientific "looks fine to me" assessment. I thought it would be relevant to share my experience pushing the chemicals past their written specs and showing results from the opposite end of the quality-control spectrum.

That posted image was developed at the very end of the developer's already over-extended lifespan. 61 rolls through a total 2 liters of solution. I understand this sounds crazy to some, but I'm only relating my experience. I will include two other unedited images from the same scene and let you be the judge of the consistency.

Frankly, I do not trust the cinestill quality control, but am unfortunately obligated to use their developer because of shipping restrictions that only allow powder chemicals to enter the country. Oftentimes the chemicals arrive already fairly oxidized and "fresh" developer has a slight (sometimes dramatic) amber discoloration. I just mixed a fresh batch of developer and my calibrated pH meter shows a reading of 10.4, which is much too high (I also cannot procure 60% glacial acetic acid to bring this pH down, if anyone has another suggestion for lowering developer pH that would be great). Thus, even my starting point is off-spec as it is. I should also note that the developer solution after 61 rolls shows a pH reading of 10.2, if anyone was curious.

In a perfect world I would be using Flexicolor liquid developer and replenishing according to spec but absent of this possibility I have adapted the workflow in a manner that I personally find acceptable and cost-effective.

I cannot offer you any suggestions re: RA-4 printing, that is outside my experience.

Thanks for the reply, originalwinslow

pentaxuser

originalwinslow said:

(I also cannot procure 60% glacial acetic acid to bring this pH down, if anyone has another suggestion for lowering developer pH that would be great).

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Cleaning vinegar from the supermarket will also work. You don't need that much. If you can't purchase even that, in a pinch you can use a plain vinegar for culinary purposes; try to obtain one that has no flavorings and colorants added. But I'm sure cleaning vinegar is available to you. It's generally around 7% acetic acid, which is fine for this purpose.

Btw, for amusement purposes - this is a scan from a 6x12 Kodak Ektar negative (fresh film back when it was shot) processed in a Rollei Digibase C41 kit. It was a 1-liter kit that was mixed 3 months prior to that, stored in a bottle with a somewhat loosely fitting cork, and it had plenty of rolls and sheets of film run through it at that point. Basically, the developer was pretty much bunk when I got here. While at first glance this may seem quite as OK as the examples we've seen earlier in this thread, these negatives are (1) unprintable and (2) a far cry from what they might have been if they had been processed properly even if scanned. It's relatively easy to come up with 'convincing' examples of overstretching c41 developer. Things break down when you improve the consistency in your process and realize how far you've drifted off from where you could have been all along. People generally don't cherish that kind of experience and most people will argue it's not really worth the $20 they saved in the process. YMMV and all that.

koraks said:

Cleaning vinegar from the supermarket will also work. You don't need that much. If you can't purchase even that, in a pinch you can use a plain vinegar for culinary purposes; try to obtain one that has no flavorings and colorants added. But I'm sure cleaning vinegar is available to you. It's generally around 7% acetic acid, which is fine for this purpose.

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Thanks koraks, I was thinking the 5% white vinegar available here would probably be sufficient to bring pH down without over-dilutiing.

koraks said:

View attachment 401424
While at first glance this may seem quite as OK as the examples we've seen earlier in this thread, these negatives are (1) unprintable and (2) a far cry from what they might have been if they had been processed properly even if scanned.

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I see what you mean. The colors of the leaves appear to have a strong shift towards blue despite the scene being relatively well-balanced otherwise. Going forward I will be more conservative with exhaustion.

You mentioned that the composition of replenisher is a more concentrated CD mixture absent of halides. I'm curious if there is a chemical recipe floating around for DIY replenisher? I haven't seen one. I assume it would have to be specifically matched to the composition of the DIY developer one is using.

originalwinslow said:

The colors of the leaves appear to have a strong shift towards blue despite the scene being relatively well-balanced otherwise.

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It's a shadow scene shot in early spring on a fairly drab day, and it leans a bit towards cyan. It can be warmed up if so desired. Which I don't think improves anything - but then again, there's awfully little to fix about this piece of compositional confusion to begin with.

originalwinslow said:

You mentioned that the composition of replenisher is a more concentrated CD mixture absent of halides.

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Not necessarily entirely without halides. IDK, maybe, maybe not.

originalwinslow said:

I'm curious if there is a chemical recipe floating around for DIY replenisher?

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Not that I know of, no. Maybe something could be extrapolated from the C41 formulas that are posted combined with the SDS and the mixing instructions for replenishers. One should be able to get close on that basis.

originalwinslow said:

I assume it would have to be specifically matched to the composition of the DIY developer one is using.

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Depends a bit on how critical you are of the end result, but I'd actually expect you could get away just fine with any commercial replenisher formula if you found one.

Then again, if you have a regular C41 developer formula (which you do, as these are around here on this forum for instance), why bother with a replenishment system? Just mix fresh what you need, when you need it. For me, that has always been most of the rationale for DIY mixing a color developer.

koraks said:

Just mix fresh what you need, when you need it. For me, that has always been most of the rationale for DIY mixing a color developer.

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Adding DIY replenishment into the process would probably just over-complicate things.

I am curious what your exhaustion tolerance for C-41/ECN-2 developer has been. 10 rolls? Do you ever extend development time to compensate?

RE: extended dev times - There is an automatic agitator on the market in the style of a simplified JOBO. It does not include any sort of heating element and automatically compensates for temperature drop by extending development time accordingly. When I used to develop without a heated water jacket the tank tended to lose 3+ degrees F. Since color dye layers develop at different rates at temperatures +- 100F I always try maintain constant temp. I have seen examples of C-41 developed at much lower temperatures (80F) and the results reflect this variation in the dye layers. Could this device actually give good results with a potentially 3-5+ degree temp drop?

originalwinslow said:

Adding DIY replenishment into the process would probably just over-complicate things.

I am curious what your exhaustion tolerance for C-41/ECN-2 developer has been. 10 rolls? Do you ever extend development time to compensate?

RE: extended dev times - There is an automatic agitator on the market in the style of a simplified JOBO. It does not include any sort of heating element and automatically compensates for temperature drop by extending development time accordingly. When I used to develop without a heated water jacket the tank tended to lose 3+ degrees F. Since color dye layers develop at different rates at temperatures +- 100F I always try maintain constant temp. I have seen examples of C-41 developed at much lower temperatures (80F) and the results reflect this variation in the dye layers. Could this device actually give good results with a potentially 3-5+ degree temp drop?

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I remember reading a thread where PE called out that the diffusion process through film layers was calibrated specifically for that temperature range and couldn't be expected to give consistent results outside of it.

I think the simplified JOBO devices like the Ago(?) are intended for people who are less concerned about that level of consistency because they're scanning.

This post shows color shifts in C-41 and ECN-2 developed at different temp ranges (thanks to VintageVisual for sharing it):

originalwinslow said:

I am curious what your exhaustion tolerance for C-41/ECN-2 developer has been. 10 rolls? Do you ever extend development time to compensate?

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I generally use it one shot. That means in practice 4-6 rolls per liter. Sometimes I use the same volume a second time if the second roll/sheet(s) isn't particularly important to me. Otherwise I don't reuse the developer.

originalwinslow said:

Could this device actually give good results with a potentially 3-5+ degree temp drop?

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No method of temperature compensation can compensate for the effect you mentioned, i.e. differential rates of development depending on how deeply 'buried' the layer is in the emulsion stack. Whether a 3-5 degree (F) temp drop is very relevant, I couldn't say. It sounds like pretty much the most you would see a tank deviate if you start at around 100F/38C and just put the tank on a non-heated surface for the 3m15 or so it takes to complete development.

farpointer said:

This post shows color shifts in C-41 and ECN-2 developed at different temp ranges (thanks to VintageVisual for sharing it):

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As always with tests like these it's hard to judge what part of the color shift was due to variation in the negatives and what part might have originated in the scanning and digital color balancing part. The most optimistic reading would be "we can't know for sure".

Whelp, I decided to run a back-to-back test of the exhausted developer vs fresh keeping all other factors equal to see just how incongruent the results would be.

I am here to eat crow.

I'll start with the bad. The exhausted developer with 61 rolls under its belt (2L total working solution, 500ml dumped and replaced with 500ml fresh at 30 rolls) shows significant yellow color shifts in the highlights that are essentially impossible to correct for using basic white-balance adjustments. While it is a stronger shift than I recall seeing in my devs, the results are indisputable. Skin tones are practically jaundiced. It's an almost unusable image that would require heavy editing to salvage.

That being said, overall contrast, dynamic range, sharpness, saturation and grain are essentially equal. The image could be fairly workable if one was ready to jump into photoshop to correct the colors. But the comparison shows that the exhausted developer clearly gives less-than-ideal results for color accuracy.

I used Vision 3 500T for the test (cross processed c-41), shot at f8 in natural evening light. I metered off a gray card, but realized afterwards that my ISO was set to 1000 so I inadvertantly metered one stop under. I think for this test that detail is mostly irrelevant. Fresh developer time was 3:15, exhausted was 5:15. Images were converted in NLP with the auto-neutral white balance applied, no additional edits. The color differences are also clearly visible in the negatives.

Developer is cinestill @ pH 10.3 which I adjusted down from the very high 10.5 when freshly mixed. I used 5% distilled white vinegar to bring it down. The goal was typical spec pH of 10.25 but I quickly noticed that 5% acidity is too weak to bring down pH by .5 without introducing a non-insignificant amount of dilution. It took about 50-60ml to lower the pH just .2 so bringing it down all the way would lead to roughly 10% dilution of the 1.5L solution. I debated which would affect the image more, pH or dilution, and decided to just leave it at 10.3 for now. For significant pH adjustment such as this I would say a more concentrated acid is required. The pH of the exhausted developer was 10.2.

Needless to say, this "replenishment" scheme does not work, or at least shows marked differences from using fresh chems. The question remains at what exhaustion point this variation starts to become noticable. Also, whether a cross-processed ECN-2 film shows a more dramatic shift than a c-41 film. Questions for another day.

Thanks for inspiring me to check my work. How does it stack up compared to expectations?

originalwinslow said:

That being said, overall contrast, dynamic range, sharpness, saturation and grain are essentially equal.

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On a color-corrected output. What you're comparing is not the negatives. You're comparing images that are produced from a negative, with a very, very heavy dose of digital editing. But you may not be realizing this due to the automation involved.
If you want to do a real comparison, take a flatbed scanner or a digital camera and a light table, and photograph both negatives at the same time, side by side, so they get the same exposure etc. Then do the color balancing on that compound image so again, both negatives get the same treatment. Then look at the differences. You'll note the differences are much more dramatic than they now seem.

originalwinslow said:

The color differences are also clearly visible in the negatives.

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By the time color differences are visible on the actual film, even if it's a very subtle difference to the naked eye, the process is totally out of whack.

originalwinslow said:

The question remains at what exhaustion point this variation starts to become noticable.

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That's the million dollar question indeed, and in practice, it turns out that only a process involving calibration strips and densitometry gives hard & fast answers. But that's kind of a chore (and potentially expensive) for home users. I think you're beginning to see why I (and many others) lean towards the conservative side and go for one-shot use most of the time. I decided at some point that it would make more sense trying to bring the cost of the developer down so I could get consistency at a low price, instead of trying to economize through reuse.

originalwinslow said:

How does it stack up compared to expectations?

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See above; the difference you're showing are only the tip of the iceberg, with the majority pressed down underwater by NLP's color-correction magic.

Btw, thanks for having the courage to post this; I'm sure many people would have preferred to keep a lid on it if this happened to them. The fact that you are transparent on your findings will surely help others!

koraks said:

On a color-corrected output. What you're comparing is not the negatives. You're comparing images that are produced from a negative, with a very, very heavy dose of digital editing.

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Absolutely. It seems that with each dev I see more of what NLP is doing to correct significant deficiencies of the negative in order to create "pleasing" results. At the very least sharpness and grain are not affected by the algorithm, which are two factors I believed would be affected by longer dev times/exhausted chemistry.

Yes, I agree for the most part on the sharpness/grain bit. There's a minor factor here that relates to the extremes of the curve that are presently not represented in your digital files. I think you will in fact see a distinct difference in the appearance of the grain (its color as well as apparent size) in the very deepest shadows. But since this is outside the bandwidth of a properly exposed negative (i.e. it would mostly show up when trying to recover very underexposed images), you might argue it's not very relevant. A similar effect is likely present in the highlights. Finally, there are some acutance differences that may be too subtle in the present examples to show, but that could appear on further analysis.