C-41 troubleshooting

nickandre

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markbarendt

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thisismyname09 said:
I've been looking for a while but I've been unable to find any.

The lowest I've found previously was a little over $100. I seem to be bad at googling. Thanks.
Click to expand...

No you are not bad at Googling, don't fool yourself it took a significant amount of time to figure this out.

The biggest frustration I have with C-41, is not the process; it's the mystery and myths that surround it.

We end up doing chemical back-flips like you were trying from a simple lack of knowing what our options are.
 

DarkMagic

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To Photo Engineer

P E: I have used Digibase C41 for a long time. Now im having a big batch of Flexicolor LORR Replenisher developer ill try to match Digibase. First i mix one litre replenisher solution who then is mixed down to tank solution with water and starter. Used in a JOBO for 3:15 6 min bleac (RA) Then C41 RA fix. All wash cycles.

I have done some densitometer readings. Looks like i add to much water, but following KODAKs advices from their tech pub on it, Can you see out from my added curves whats wrong?

The density readings are from machbet/x-rite colorscheckers neutral steps.
 

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Photo Engineer

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I cannot begin to evaluate this spread sheet. It is totally alien to me in overall format and content. Sorry.

I'm not sure what the problem is, if any. I don't know if the Digibase results are OK or not for starters, and then by comparison IDK what is wrong with the EK kit.

What I need is a plot of Density (y axis) vs Log Exposure (x axis) for each process. This will clearly show me dmin, relative speeds and contrast with crossover.

Thanks.

PE
 

tnabbott

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I have purchased from Liberty and can say they are a good place from which to obtain these chemicals.
 

DarkMagic

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In the exelfile, there is a y/x-axis with exposure/density chart/diagram. JPG screenshot is added here
 

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Photo Engineer

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Well then, that is what is confusing me. Those curves look nothing like any C41 film curve I have ever seen! And so, I cannot give any real conclusion to you about this.

A C41 curve set should be a trio of parallel or near parallel lines with yellow on top, then magenta and then cyan where the cyan occupies the position of a normal B&W film H&D curve. I see little resembling that here. Sorry.

PE
 

DarkMagic

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Im not good enough with exel to plot the RGB-values into a curve system. So only the neutral densities is in the curve graph. All the RGB in respectly order, are in the columns with letters.
 

pentaxuser

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Photo Engineer said:
You need a stop/clear between the developer and the bleach. See my other post on this!

PE
Click to expand...

I know I have come into this one late but what is the difference between a stop/clear and what the OP is doing? He mentions in his post using a stop then wash after the developer and prior to the bleach

Thanks

pentaxuser
 

Photo Engineer

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In another thread it was mentioned that a ferricyanide bleach was used. If this is so, then a stop/clear must be used before ferricyanide to prevent dark orange stain to form. Color developer reacts with Ferricyanide to form dyes instantly. This is what the samples resembled in the OP and that is the advice I gave.

OTOH, a bleach based on Iron III can give an orange stain like that due to formation of Ferric Hydroxide, but modern bleaches are designed to avoid that problem so I discounted it in the answer. Perhaps I was wrong to do so.

PE
 

pentaxuser

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Thanks PE I understand the need for a stop/clear after dev and before using a ferricyanide bleach but in what way is a stop/clear different from the process the OP had listed prior to your post about a stop/clear in which he seems to have used a stop then a wash prior to bleach. Is stop then wash different to what a stop/clear is?

So still confused as to what the essential difference is between a stop then wash and a stop/clear.

Thanks

pentaxuser
 

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There was another thread at the same time that had a problem like this and used a ferri bleach. I referred to that in my OP here. And, a stop then wash is different than a stop/clear in a ferri process due to the absence of a clearing agent. Often, a wash is insufficient to remove all color developer from a coating but a clearing bath with sulfite and acid will do the job just fine.

That is the reason for my recommendation. If no ferri is used then a stop then wash would be OK, but would not explain the high dmin of the negatives. That leaves me with 2 major causes, carryover of developer in to ferri or bad bleach. I mentioned both.

PE
 

pentaxuser

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Thanks PE I thought there must be something different in a "clear" but what I was completel ignorant of what it was.

pentaxuser
 

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For proper processing, if you fix before bleaching then the sulfite in an acid fix will act as a clear. However, you must also fix after the ferri bleach.

PE
 

DarkMagic

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New chart/v´curve

I have now altered the way my densitometer plots to EXEL So you can have the curves in LOG/DENSITY axis. I have also changed to Fuji Hunt Chemistry and used Fuji negative control strips.
 

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Photo Engineer

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DarkMagic said:
I have now altered the way my densitometer plots to EXEL So you can have the curves in LOG/DENSITY axis. I have also changed to Fuji Hunt Chemistry and used Fuji negative control strips.
Click to expand...

The attached curve should give you an idea of what a color negative film curve looks like. This is an experimental coating that has severe defects causing crossover. I dug one out of an old file for you.

Your reading of a step scale in R/G/B space should resemble a portion of this curve, either better in shape or worse. You should have 2 sets of 3 curves, one with one chemistry and another with the other chemistry. This is needed to make any sense of what you are describing.

Sorry.

PE
 

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