page with c41 recipes

narigas2006 · Jun 18, 2007

hi all,

I know I saw it here somewhere but after searching and searching with a dial-up, i apologise for the trouble, but does anyone remember a link to a page with c41 chem recipes (that was once posted here)? many many thanks.

Nick Zentena · Jun 18, 2007

http://www.bonavolta.ch/hobby/en/photo/c41_ra4_chemicals.htm

I've only used the developer.

Photo Engineer · Jun 18, 2007

This site does not have the optimum RA or C41 formulas IIRC.

There is another one that is better. The C41 developer is incomplete, but I would have to do some research here to get the correct developer.

PE

srs5694 · Jun 18, 2007

IIRC, the RA-4 developer to which PE refers is Steven Keirstead's. I've never used it because it requires some pretty obscure chemicals that I've never bothered to track down. I have used the simpler RA-4 developer on the page to which Nick links, with what I consider to be good results -- but you might disagree that the results are good. I don't trust the blix on that page -- the proportions of the ingredients are way off from other RA-4 blix formulas I've seen. Financially, mixing blix yourself saves little or no money, so I buy commercial blixes.

I don't know if PE has a specific page with C-41 formula in mind, but I've got a few bookmarked: (there was a url link here which no longer exists) two, (there was a url link here which no longer exists) Of these, I've only used #1 (NCF-41), and found that it produced variable results -- sometimes fairly good but sometimes not. Typically it produced thin negatives. Mostly I've been using Paterson Photocolor II, but my supply of that is almost gone, and since it's no longer being made I'll probably either try another mix-it-yourself formula or switch to Kodak's Flexicolor developer. (I'm already using Kodak's bleach and fix; the C-41 blixes I've tried have all been unsatisfying.)

Photo Engineer · Jun 18, 2007

Of the above, the Keirstead's RA formula is most nearly correct and "two" and "three" are the most nearly correct, but differ in iodide which is an essential ingredient and is missing from the formula referenced by Nick.

"One" is hopelessly incorrect and unusable due to film thickness differences which alter activity.

If I can locate appropriate formulas, I will post them someday.

PE

markkubis · Jun 21, 2007

Photo Engineer said:
Of the above, the Keirstead's RA formula is most nearly correct and "two" and "three" are the most nearly correct, but differ in iodide which is an essential ingredient and is missing from the formula referenced by Nick.

"One" is hopelessly incorrect and unusable due to film thickness differences which alter activity.

If I can locate appropriate formulas, I will post them someday.

PE

I'm interested in making up my own C41 solution and don't know which one would be best. Thanks for eliminating one C41 recipe (Nick's.) However, we are still left with six. I'd love to know which C41 you think would be most correct for hand tank development at home: "two" or "three". "Two" has 5 different C41 recipes so not clear which one is the best one out of these or whether "three" would be better. Or if you could locate some formulae that you know to be good it would be also be greatly appreciated. Thanks.

Photo Engineer · Jun 21, 2007

Reference two only has one formula with Iodide that I can see, and that one looks more nearly correct to my old tired memory. I would go with that one which is the first one in the list.

I would suspect any developer formula without iodide and any set of formulas that suggests using a blix. To my certain knowledge, no blix execpt the ones we patented will remove silver totally from E6 and C41 films and will result in muted color and higher grain.

I am currently working on a blix formula based on my EK work. I hope to make it available soon.

PE

OldBikerPete · Jun 21, 2007

Photo Engineer said:
<snip> .....

If I can locate appropriate formulas, I will post them someday.

PE

I will be impatiently waiting with bated breath, salivating.

Photo Engineer · Jun 21, 2007

You have to understand that I could not walk out of Kodak with proprietary information. So, as a result, I have to reconstruct this data from patents and memory.

I'm working on it.

I'm sorry for the problems this might create.

PE

OldBikerPete · Jun 22, 2007

Photo Engineer said:
You have to understand that I could not walk out of Kodak with proprietary information. So, as a result, I have to reconstruct this data from patents and memory.

I'm working on it.

I'm sorry for the problems this might create.

PE

Oh, I understand - truly I do.

Nevertheless..........................................................

markkubis · Jun 22, 2007

Photo Engineer said:
You have to understand that I could not walk out of Kodak with proprietary information. So, as a result, I have to reconstruct this data from patents and memory.

I'm working on it.

I'm sorry for the problems this might create.

PE

Yeah we all understand that. We also wouldn't want Kodak's recipes because no doubt they would be over complicated for the home mixer with lots of hard-to-find ingredients.

However, we would all welcome simplified recipes for C41, RA4 and E6 process that work maybe 90% as good as Kodak's. We'd use distilled water if necessary to simplify the recipes further.

It's just that I keep throwing away opened proprietary home kits because a year or more can pass before I process the next batch. I prefer to process films myself. I've just had 5 films lost in the post on the way to a commercial lab of my recent trip to Istanbul. This has really got to me as the purpose of the trip was photographic. The films may still turn up at the lab but it's been 10 days so far and the lab is only 100 miles away. I don't want to take this risk again. I've tried the mini-lab in my local town but they are expensive and have disappointing quality (I suspect they stretch their chemistry) and only offer 7x5 rather than 7.5x5 prints.

Photo Engineer · Jun 22, 2007

Mark;

Simplified formulas often just do not work properly with all films. Current C41 blixes are a good example of this but it is very much also the case with developers. So, there is no truly simplified formula set for C41 or E6. They are what they are to meet given aims in speed, grain, sharpness and color gamut.

In addition, the real formulas are designed to work with all color films, but the simplified ones are often only usable with one film as they were only tested with one film.

There was a rather long article with data in the old Darkroom Techniques, about 10 years ago describing this very subject.

The C41 chemistry is the least 'exotic' of them all, next is RA, and then E6. Kodacrhome is the most complex by an order of magnitude.

PE

page with c41 recipes

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