Deficiencies in DIY C-41 Chemistry

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Finally got around to running a second test on DIY C-41 chemistry. Results are sub-par, specifically in the red channel. Red veers toward orange and appears rather de-saturated. Color mask is also clearly different from the other half of the same roll developed in kit developer. Top negatives developed in kit, bottom in the DIY.

It may be difficult to diagnose precisely what is going on here. I used the PE formula omitting the DTPA and potassium iodide mixed in this order. I also added 3g metabisulfite rather than 2.78g. The CD-4 fizzed upon contact with the rest of the solution, still unclear to me if this affects the chemistry. I could try pre-mixing CD-4 with water before introducing.

potassium carbonate - 34g
potassium bicarbonate - 2.3g
sodium sulfite - .4g
sodium metabisulfite - 3g
potassium bromide - 1.5g
HAS - 2.4g
CD-4 - 4.5g

pH ~ 10.05

The sample photos are non-scientific, but the red in the shoe as well as the dog collar are clearly affected. The gray floor also has a strong red color cast. Any ideas?
 

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koraks

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Looking at the negatives, it seems the DIY chemistry has resulted in a lot of yellow dye formation, but not much magenta and cyan. The color balance is shifted dramatically.

What did you use for time and temperature? I love the boston.
These are relevant questions, and I'd add reliability of the pH measurement as a possible factor. And of course errors in weighing out chemistry.
 

pentaxuser

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Just as a matter of curiosity, the kit seems to have got rid of the red cast in the DIY but altered the colour of the boston from black to brown so what was the actual colour of the dog

Thanks

pentaxuser
 

RPC

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I use this formula with excellent results. I too omit the iodide and DTPA, and use distilled water to mix. I develop for 3:15 at 100F. Unlike other formulas I have tried, I never have to check or adjust the pH with this one. YMMV
 

koraks

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the kit seems to have got rid of the red cast in the DIY but altered the colour of the boston from black to brown
I'd be very hesitant to connect specific color observations to the chemistry. Yes, there's a difference, and yes, the chemistry has something to do with it. But especially when troubleshooting, what's most useful is to have a good baseline comparison that removes the influence of automatic color balancing in the digital part of the process. Fortunately, @originalwinslow has supplied us with an excellent comparison in the form of a photograph of two negative strips. We can use this to do a crude/naive color balancing for the known-good strip, so we can see what the objective difference is with the DIY-processed strip:
1751607264274.png

Note that the key difference really is in the blue/yellow channel. That effect is so dominant that there's very little basis to say anything really about other colors. After all, the blue cast in the DIY processed strip is so strong that all other hues can be assumed to be contaminated, resulting in shifts and reduced saturation. If you allow software to auto-color balance the bottom strip, what'll happen is that new color anomalies are introduced that are a side-effect of automatically correcting the dominant blue cast. If you're not aware of this, it's all too easy to believe that these side-effects are somehow due to the chemistry, even if they're just a digital artifact.

So let's be very careful in how we talk about what effect the DIY chemistry has had on color. The main thing we can state with confidence is that the DIY-processed film features a dramatically higher degree of yellow dye formation. If you look at the negative, it's also clear that both the magenta and cyan hues are lacking in the un-inverted negative, so it's to be expected that the reds and greens will be weak, while the blues are emphasized.

The reason why this is pertinent is because the blue-sensitive (yellow dye-forming) layer is at the top of the film, green/magenta is in the middle and red/cyan is at the bottom. For some reason, the developer has acted more strongly on the top layer than the underlying layers. This means that either the developer hasn't had sufficient time or opportunity to penetrate into the lower layers and/or to do its work there, but it has had sufficient time to act on the top layer.

Looking at Kodak's C-41 troubleshooting chart, a few things come to mind:
* Insufficient color developer; e.g. a weighing error made when weighing out the CD-4. @originalwinslow can you confirm that you did in fact use CD-4 and not CD-3? The latter is less active and will probably give distinct color shifts. You may also try to dissolve the CD-4 in water first as you proposed, although AFAIK there's no chemical difference with just dumping it into the mix directly. Yes, it does fizz; the CD-4 is acidic and the developer is alkaline.
* Developer is too weak overall. This doesn't easily happen if you start with dry chemistry unless you mistakenly add too much water - but that mistake is usually noticed early on. Another possible cause for anomalous activity is a pH that's off the mark. You mention a 10.05 pH, but how was this determined? In my experience, low-end pH meters are notoriously unreliable.

Finally, there's the possibility of something triggering excess yellow dye formation; i.e. dichroic fog. This can be in the domain of bleach or fixer contamination of the developer. However, this would explain only the excess density and not the lack of cyan and magenta, overall. So even if there's some kind of fogging issue going on, it's not the dominant factor.

By all means, some kind of mixing error in the developer or poor development process parameter control is the likely culprit.
 

lamerko

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I've always been concerned about this "bubbling" when adding CD. I try to avoid it whenever I can. CD4 is quite acidic, and the solution it is added to is already about pH 11. Try dissolving the CD4 together with HAS or sulfite in a little water and adding it to the main solution.
I've only tested the formula once (because I have a small amount of CD4) - the results were great. So good that they were visibly (without being measured with a densitometer) no different from those of Fuji's chemistry.
 

halfaman

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The CD-4 fizzed upon contact with the rest of the solution, still unclear to me if this affects the chemistry. I could try pre-mixing CD-4 with water before introducing.

The bubbling happens to me with commercial chemistry if I mix directly the CD4 concentrate (acidic) with the starter (alkaline). It doesn't happen if I mix them in enough water.

How much water are you starting to mix with? This recipe is for 1 liter, so you should start with something like 700 ml.
 
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pentaxuser

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I'd be very hesitant to connect specific color observations to the chemistry. Yes, there's a difference, and yes, the chemistry has something to do with it. But especially when troubleshooting, what's most useful is to have a good baseline comparison that removes the influence of automatic color balancing in the digital part of the process. Fortunately, @originalwinslow has supplied us with an excellent comparison in the form of a photograph of two negative strips. We can use this to do a crude/naive color balancing for the known-good strip, so we can see what the objective difference is with the DIY-processed strip:
View attachment 402094
Note that the key difference really is in the blue/yellow channel. That effect is so dominant that there's very little basis to say anything really about other colors. After all, the blue cast in the DIY processed strip is so strong that all other hues can be assumed to be contaminated, resulting in shifts and reduced saturation. If you allow software to auto-color balance the bottom strip, what'll happen is that new color anomalies are introduced that are a side-effect of automatically correcting the dominant blue cast. If you're not aware of this, it's all too easy to believe that these side-effects are somehow due to the chemistry, even if they're just a digital artifact.

So let's be very careful in how we talk about what effect the DIY chemistry has had on color. The main thing we can state with confidence is that the DIY-processed film features a dramatically higher degree of yellow dye formation. If you look at the negative, it's also clear that both the magenta and cyan hues are lacking in the un-inverted negative, so it's to be expected that the reds and greens will be weak, while the blues are emphasized.

The reason why this is pertinent is because the blue-sensitive (yellow dye-forming) layer is at the top of the film, green/magenta is in the middle and red/cyan is at the bottom. For some reason, the developer has acted more strongly on the top layer than the underlying layers. This means that either the developer hasn't had sufficient time or opportunity to penetrate into the lower layers and/or to do its work there, but it has had sufficient time to act on the top layer.

Looking at Kodak's C-41 troubleshooting chart, a few things come to mind:
* Insufficient color developer; e.g. a weighing error made when weighing out the CD-4. @originalwinslow can you confirm that you did in fact use CD-4 and not CD-3? The latter is less active and will probably give distinct color shifts. You may also try to dissolve the CD-4 in water first as you proposed, although AFAIK there's no chemical difference with just dumping it into the mix directly. Yes, it does fizz; the CD-4 is acidic and the developer is alkaline.
* Developer is too weak overall. This doesn't easily happen if you start with dry chemistry unless you mistakenly add too much water - but that mistake is usually noticed early on. Another possible cause for anomalous activity is a pH that's off the mark. You mention a 10.05 pH, but how was this determined? In my experience, low-end pH meters are notoriously unreliable.

Finally, there's the possibility of something triggering excess yellow dye formation; i.e. dichroic fog. This can be in the domain of bleach or fixer contamination of the developer. However, this would explain only the excess density and not the lack of cyan and magenta, overall. So even if there's some kind of fogging issue going on, it's not the dominant factor.

By all means, some kind of mixing error in the developer or poor development process parameter control is the likely culprit.

Thanks for the very extensive reply I had thought in my naivety that both pics were faithful reproductions of the prints or actual negs produced by the DIY kit and commercial kit respectively so I thought the red cast I could see was a genuine red cast. So was it a red cast or was it not from what you or others were looking at ?. Secondly the dog did seem to change colour as well. Did it to you or others who viewed what the OP showed us ?

Thanks

pentaxuser
 

Rudeofus

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If @koraks analysis is correct and the top most layer saw more development action than the two bottom layers, then this would fit nicely with the "omitted iodide" statement from @originalwinslow . That's the whole point of the iodide in C-41 CD and E-6 FD, that then top most layer grabs all the iodide it can find and is more restrained than the lower layers.
 

koraks

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My experience is that omitting iodide from a C41 formula does in no way have as profound an effect as shown here. Not even close. The effect is very, very subtle and in fact it's very hard to tell whether it's there to begin with.
 

RPC

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I have observed no obvious effects from omitting the iodide. I have used formulas mixed with only CD-4, carbonate, sulfite and bromide and still got images with no obvious defects, although a significant pH adjustment is necessary and shelf life is shortened.
 
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What did you use for time and temperature? I love the boston.

3:15 @ 100F

can you confirm that you did in fact use CD-4 and not CD-3? The latter is less active and will probably give distinct color shifts. You may also try to dissolve the CD-4 in water first as you proposed, although AFAIK there's no chemical difference with just dumping it into the mix directly. Yes, it does fizz; the CD-4 is acidic and the developer is alkaline.
* Developer is too weak overall. This doesn't easily happen if you start with dry chemistry unless you mistakenly add too much water - but that mistake is usually noticed early on. Another possible cause for anomalous activity is a pH that's off the mark. You mention a 10.05 pH, but how was this determined? In my experience, low-end pH meters are notoriously unreliable.

I am 99% sure I used CD-4. I just mixed a fresh batch of developer using this same formula (definitely used CD-4) and plan on testing it in the next few days. I tried pre-dissolving CD-4 to see if that makes any difference. Doesn't seem that the fizzing (release of CO2?) would cause this dramatic of an anomaly but I'll eliminate it as a factor. My pH meter is on the cheaper end, but I two-point calibrate each time before testing my solutions. It reads the pH 10 buffer correctly so I don't have much of a reason to doubt its accuracy at this point...other than the wide consensus that these low-end meters aren't particularly viable. The fresh DIY developer I just made gave a pH reading of 10.1 which should be correct.

Over dilution is not the issue, definitely 1 liter of solution.
 
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Mr Bill

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My pH meter is on the cheaper end, but I two-point calibrate each time before testing my solutions. It reads the pH 10 buffer correctly so I don't have much of a reason to doubt its accuracy at this point...

Hi, I wouldn't be too confident that your color developer pH are correct. I appreciate that you ARE calibrating your meter. The real issue is with the pH electrode (I'm assuming the typical glass bulb style). Color developers are a special sort of thing, and not all pH electrodes can read them correctly.

Kodak used to specify certain (expensive) electrodes for color developers. They don't say that other electrodes won't work, only that it's up to the user to determine.

This is something I used to (once upon a time) read a lot of samples, using research-grade pH meters. On occasion we'd look at different pH electrodes; they were typically too different from the Kodak-rec electrodes to be usable for us. (We kinda felt that, on a good day, we could get a correct color developer pH reading within about 0.02 pH units.

If you're gonna use a non-proven meter/electrode combination, I would recommend to get your aim pH value by actually mixing a fresh commercial color developer (preferably by Kodak or Fuji-Hunt?). Then whatever THAT measures, with your calibrated meter, becomes your aim pH value.

If you want more info on pH electrode recs, Kodak's H24 Motion picture manual, available online, has a pretty good rundown, I believe.

I just looked it up - it's in module 3 of the H24 manual. Search for the method called ULM-191-2.

I think the document is fairly old, but I'm gonna give a brief quote: "Because of the effect of the complex matrices of photoprocessing solutions on the glass membranes of pH electrodes, a significant difference has been observed between different manufacturers pH sensing glasses."

Ps, I've never used one, but my understanding is that there are now solid-state pH electrodes (isfet?) that are not affected by the same things.
 
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Hi, I wouldn't be too confident that your color developer pH are correct. I appreciate that you ARE calibrating your meter. The real issue is with the pH electrode (I'm assuming the typical glass bulb style). Color developers are a special sort of thing, and not all pH electrodes can read them correctly.
I thought this might be main issue with the cheap meter, that the electrode is simply incapable of getting even a somewhat accurate reading due to the composition of the chemicals. I went through the H24 manual and found the recommended electrode available on ebay for $50 which isn't too bad. Not sure if these electrodes go bad in storage, though. Ebay is always a bit of a shot in the dark. I would also need a halfway decent meter with BNC connector, if anyone has suggestions.
If you're gonna use a non-proven meter/electrode combination, I would recommend to get your aim pH value by actually mixing a fresh commercial color developer (preferably by Kodak or Fuji-Hunt?). Then whatever THAT measures, with your calibrated meter, becomes your aim pH value.

Would if I could. Part of the reason I am mixing up DIY is the lack of availability of liquid chemicals where I am located. The best reference I have is this DIY formula that, as other users have described, generally mixes out with a correct pH of 10.1-10.2 and does not require adjustment. This was reflected in my meter's reading, giving me a bit of confidence.

I have been using Cinestill powder developer for years, but do not trust their quality control enough for it to be a good reference point. Nor do I even know what their developer pH should be. The last batch I mixed gave a reading of 10.4, and the roll I developed (before I ended up adjusting pH down to 10.2) came out with very high contrast. I took this to mean that the high 10.4 reading was potentially correct. As others have discussed, developer mixes intended for reuse as opposed to replenishment may intentionally have a high activity upon mixing to compensate for drift over the course of their usage lifespan. Point is, I don't know if that reading was a result of bad chems, intentional high-activity, or an innacurate meter.

Without a dependable reference solution or electrode I am floating a bit in the unknown. If I really care to get consistently accurate pH readings it seems I need to invest in lab-grade equipment.
 

Spektrum

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I would also need a halfway decent meter with BNC connector, if anyone has suggestions.

Pay attention to this pH meter: VOLTCRAFT PH-100 ATC
In Europe, the price is below 100 EUR, you can find a bargain at a much lower price.
Interchangeable electrode with BNC connector. Take a look at the technical specifications on this page:


I have seen its reviews on a Polish auction site and it has only positive ratings.
People appreciate its accuracy, consistent with the manufacturer's declarations, and the repeatability of measurements.

It would be good if other people on this forum confirmed its usefulness for measuring pH of color chemistry, if they have any experience with this device.
It is a very popular pH meter, available everywhere in Europe. I don't know how it will be in your region.
 

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koraks

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People appreciate its accuracy, consistent with the manufacturer's declarations, and the repeatability of measurements.

Under what conditions though? As @Mr Bill has pointed out, photographic developers are a bit of an exceptional case.
What's nice about the Voltcraft unit is that it comes with a little bottle that invites you to properly store the electrode when it's not being used. It may last a little longer that way. My experience with low-end pH meters (price-wise, this is still low-end) is that the probes work OK for some time; sometimes a few weeks, sometimes a few months. And then invariably they start to drift out of calibration and can no longer be calibrated.
 

Spektrum

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I don't know in what conditions. I think that in the current summer time a lot of people use it to test pH in their pools.
But this pH meter was recommended by my friend (who runs his own photo lab) from the Polish Korex forum.
As for those electrodes for $50 on Ebay (CORNING 476024), unfortunately I have great doubts about their current efficiency. They look like 20-year-old warehouse finds and these electrodes have probably been dry for 15 years. Electrodes should be stored in KCl.
 
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Under what conditions though? As @Mr Bill has pointed out, photographic developers are a bit of an exceptional case.
What's nice about the Voltcraft unit is that it comes with a little bottle that invites you to properly store the electrode when it's not being used. It may last a little longer that way. My experience with low-end pH meters (price-wise, this is still low-end) is that the probes work OK for some time; sometimes a few weeks, sometimes a few months. And then invariably they start to drift out of calibration and can no longer be calibrated.

My first electrode died in about 2 months. Properly stored in KCL solution, didn't matter, thing went totally haywire. Luckily it was so far off/wouldn't calibrate thus I never thought that it was maybe still accurate. Manufacturer kindly sent me a new one for free, but that was probably a one-time offer. New electrode calibrates well, question is for how long. I understand why people get fed up and stop using them altogether.

Correct me if I'm wrong but for example the Voltcraft meter wouldn't wear out/drift over time as it simply reads the information provided by the disposable electrode? The wear and tear is limited to the electrode?
I don't know in what conditions. I think that in the current summer time a lot of people use it to test pH in their pools.
But this pH meter was recommended by my friend (who runs his own photo lab) from the Polish Korex forum.
As for those electrodes for $50 on Ebay (CORNING 476024), unfortunately I have great doubts about their current efficiency. They look like 20-year-old warehouse finds and these electrodes have probably been dry for 15 years. Electrodes should be stored in KCl.

I figured as much.
 

Rudeofus

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If you contact Keten, they might be help you get the right thing. They sell chemistry and some lab equipment and seem to offer photographic development services. Other than that I have dealt with Greisinger from Germany, they have a decent selection of pH meters and probes. 10+ years ago they had a special pH probe made for photographic solutions with some Potassium Nitrate electrolyte. The chemical name brought back bad memories from school times, so I never bought one.

Reading through the description of this "Corning 476024" it's a standard run off the mill glass electrode with liquid KCl electrolyte, maybe this was something special back then, but now it's quite available.
 
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