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
 
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