DIY C-41 and ECN-II chemistry 2019

Cholentpot

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I've been looking into mixing my own developer and bleach to save on cost. My last run-in with a 1L kit was a little bit of a disaster. Pair that along with the lack of availability currently of small color kits I've decided it might be time to jump in and mix up my own stuff.

I've found some good sources of recipes online. They tend to lack any stabilizers but I don't really mind that. What caught me so far is the cost of CD-3 and CD-4. The cost of mixing up your own chemistry isn't so bad until I had to factor in the price of the CD-3/4. At that point the cost doubles. It's not terribly expensive but I am looking for a decent priced source.

Most of the instructions and recipes I've looked into are a few years old. Has anything changed currently? Any veterans out there willing to share their experience and tell me not to bother with this whole thing?

Thanks.
 

koraks

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Ah too bad, then shipping would take the fun out of it. Artcraft is probably your best bet.

As to formulas, for C41 search on this forum for formulas. Photo Engineer posted an approximation some years ago: https://www.photrio.com/forum/threads/c41-formulas.142062/
Also have a look at the various iterations @stefan4u went through about 10 years ago: https://www.photrio.com/forum/threads/color-negative-developer-near-to-c41.42731/
I have tried several approaches including some of the ones listed above as well as the very simple Bonavolta formula: https://www.bonavolta.ch/hobby/en/photo/c41_ra4_chemicals.htm
In the end, results were all pretty close when the prints were filtered for correctness, but color balance was certainly different for the various formulas (so differences in filtration). There were no very apparent quality differences to my eyes, but I didn't do measurements like stefan4u did, so my assessment is very subjective.

As to ECN-2, google for the Kodak developer formula, it's published and you can fairly easily recreate it. I modified the chemistry in some minor ways to suit the materials I had available and it seemed to work, but ECN-2 just never will print quite right onto RA4 paper so I put the whole ECN-2 project into the fridge.

BTW, for C41 I decided some months ago to go the 'official' route and got some Fuji minilab C41 chemistry and I've been using that since. It's kind of easy to work with and color filtration is more in the vicinity where you'd expect it, but again, the quality differences in real world prints between the Fuji product and various DIY solutions is not very apparent to my eye.
 
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Cholentpot

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I found this on https://jamesharrphoto.blogspot.com/2017/10/diy-color-dev-comparison.html

It looks simple enough to try. Are there any major problems with it?
 

Anon Ymous

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Cholentpot said:
I found this on https://jamesharrphoto.blogspot.com/2017/10/diy-color-dev-comparison.html

It looks simple enough to try. Are there any major problems with it?
Click to expand...
His C41 formula has no potassium iodide. This alone is a problem, because colour balance will be off to some extent. Iodide acts as a restrainer on the top layer for the most part, bit equally across all layers. It seems to be a very basic formula. Will it give a colour image? Of course it will, but it may have all sorts of problems like casts and, even worse, crossovers. If RA4 printing is not something you're interested in, then it might not be a huge issue, but even so, correcting the aforementioned crossovers can get tedious, no matter how good your Photoshop skills are. The formulae by Photo Engineer and stefa4u are certainly a better choice.

Now, apart from this, a formula usually has a target pH. It is easy to miss target pH and this means that a pH meter is a must IMHO, combined with a set of buffer solutions for calibration. Now, considering your location, you can probably source minilab chemicals fairly easily. Bleach is definitely something to consider buying, simply because it has a very long shelf life, if not indefinite. C41 fixer is also fine to buy and can be used with BW film and paper as well. Now, if you think it is worth mixing C41 developer, go for it. In the end, it is up to you to decide if it is worth the effort or not...
 

Anon Ymous

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koraks said:
Yes, you need a somewhat decent meter. The cheap yellow ones running about $10 from aliexpress aren't good in my experience.
Click to expand...
They're not particularly accurate, but better than nothing IMHO. But I can't say I know very much about them. Besides, there's more than one kind of them. There are the very basic ones with a single calibration point. They're ok-ish if you don't measure anything rather far from the calibration point, so a buffer solution close to the target pH is required. Then there are also those with the two calibration points, where the pH 7 buffer is used to adjust offset voltage and the pH 10, or 4 buffers adjust the slope. These should in theory be considerably more accurate over a broader range. Which one have you tried?

Regardless of all of that, the whole pH meter thing is a can of worms...
 

koraks

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I've tried the omnipresent yellow ones with two decimals and 3 calibration points. I've never been able to calibrate them on all three points; the 9.86 point always drifts a couple of tenths within a minute, and all three I tried showed variations among each other of sometimes more than a full point. I gave up on them and got and slightly more expensive one (still cheap though at something like €23) with temperature compensation and TDS function. Not sure if it's accurate, but I have the impression it is better than the other ones. Of course I can't be sure...
 

Anon Ymous

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Oh, that bad, I see...

In a case of eternally drifting pH meter I had, it was the batteries that it came with that were almost depleted on arrival that caused the problem. Changing them made the meter usable, although accuracy was always debatable. And yes, the €23 meter seems like a far more reasonable choice.
 

Rudeofus

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In all these years of experiments, I never had a problem with a meter being slightly inaccurate. The big problems I had came when my calibration went awry and I lost trust in my measurements. This is when things really fall apart, and when you are stuck with a meter that gives you nice numbers with two significant digits after the comma, but you don't know whether at least the digit before the comma is correct.

Therefore: yes, do spend good money on a meter, and also spend enough on buffers (either by learning and practicing how to mix them, or by ordering good ones) to make your pH measurements trustworthy. You will - at some point - run into situations where your negatives come out with too much base density or too little contrast or whatever, and that's the point where you really really want to know whether your C-41 CD had the right pH. Not down to 0.001, but at least in the ballpark. Silly me whined and moaned to Stefan about foggy results with his C-27 formula, until I discovered, that Disodium Phosphate comes in different hydrations, which caused my pH 7 calibration buffer to be off.
 
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