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  1. #1

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    C-41 homebrew - Really doable? Or Purchasing problems

    OK, first post here. Hi, all.

    My intent is to mix my own C-41, in particular the developer. While I am not a chemist, I am capable of following instructions and reading up on backgrounds, including MSDS sheets.

    Disclaimer - I have no intent of proclaiming self mixing as the only way to go, saying its better or worse than pre mixed stuff or do a cost analysis. I only wish to mix my own out of curiosity and to gain a control by knowing what is in my developer.

    The last few weeks I have spent a lot of time surfing for recipes, formulas, etc. through apug.org, www.largeformatphotography.info, photo.net and lots of other sites. Even some patent sites the last few days e.g. European patent office: http://v3.espacenet.com/textdes?DB=E...&QPN=US5827635

    I came up with only two leaving aside the ones in various patents, like the one in the link above. These are also mentioned in a recent post here by srs5694: http://www.apug.org/forums/forum40/18144-new-c41.html Well done!

    What I did find is a lot of people saying 'yep, can be done' mostly referring to the info given here: http://www.bonavolta.ch/hobby/en/pho..._chemicals.htm.

    I have now contacted several dealers first in the UK (where I live) then USA and the result is: I cannot get the core chemicals.

    e.g. http://www.process-supplies.co.uk/ and http://www.silverprint.co.uk/
    don't do Hydroxylamine Sulfate and Ferric Ammonium EDTA. Never mind Formaldehyde or Sulphuric Acid. General argumentation: EU laws, health and safety regulations. A third UK supplier Rayco Chemicals, I just talked to on the phone. The very kind new owner has bought the company in Feb 2005. There is no website yet. The gist: He is unlikely to purchase new stock of colour chemistry (e.g. CD3, CD4) - there is no market. If there is old stock, that will be sold of course. All dealers mentioned regulations regarding storage and handling as, by now, major hurdles.

    Attempting to contact three US suppliers, I only got a response from The Formulary http://www.photoformulary.com/ They cannot send CD-4 and Hydroxylamine Sulfate to the UK - hazardous chemistry.

    Is there anybody out there that still mixes chemistry and has actually purchased some in the, say, recent months? In particular in the UK/Europe

    Has self mixing C-41 (probably E6 as well) been killed of by regulations on the one hand and quickly dropping demand on the other?

    I'd be happy to hear your thoughts - expecially those of any home brewers.

    Ta, Martin

  2. #2

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    I only mix the C-41 developer and stabilzer myself. All the chemicals are [or at least at the time] could be easily gotten from

    http://www.jdphotochem.com/

    I don't know if they ship to the UK but if they do the cost of the shipping would hurt.

    I can't see any reason to mix anything but the developer and maybe the stabilizer. I know the bleach isn't cheap but it keeps fairly well. The fixer shouldn't be an issue for you to pickup. It also keeps fairly well. If you can find a supplier selling to mini-labs etc then see about buying big [5 litre or maybe 2litre no smaller] jugs of bleach and fix.

    If you really want to mix your own bleach and fix then skip the blix. Use the alternative bleach and fix.

    The demand for CD-4/CD-3 isn't set by the home market it's by people like Kodak,fuji etc mixing huge amounts of this stuff.

  3. #3

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    Hi Nick,

    I'll check out JD. But agree the shipping costs are usually painful. Someone wanted US$10 to send a step tablet.

    I agree, that the only real value is in mixing the developer. The rest does not have a major impact on image formation in comparison, so I am happy to go with of-the-shelf branded stuff. Though I will also check out the 'alternatives' regarding obtainability.

  4. #4

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    Shipment by air has more restrictions than shipment by ground. This would be a problem when ordering from the US. You might instead try locations in Europe for chemicals, I know that there are people in Germany who make there own processing solutions.

    Hydroxylamine is a known carcinogen and probably the hardest of the ingredients to obtain. CD-4 is a skin irritant and I wouldn't eat it but not all that dangerous. Check with a university to obtain a small amount of formaldehyde since it is used to preserve specimens. The ferric-EDTA used in the bleach should be available as it is sold as a source of iron for house and garden plants. However, I find it too be rather slow in its bleaching action and prefer to use the E-6 ferricyanide bleach instead. Everything else is pretty much the same as for B&W processing.

    Keep trying and don't give up just yet. Contact some camera clubs and see if they have sources for photochemicals in Britain. Thankfully the US and Canada have not yet reached the same level of paranoia that the UK apparantly has.

  5. #5
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    In order to reproduce your results from hand mixes of C41 or other color developers, you must be within about +/- 0.1 pH units at 20 deg C with a calibrated pH meter.

    In addition, you must be within +/- 0.1 grams in weight of some of the components, and in the case of one ingredient, you must be within about +/- 1 mg (IIRC - I would have to go look it up).

    This is mainly for color balance, edge effects and grain as the layers interact with each other and the interaction must be controlled precisely.

    This is why I feel it undesirable to mix color chemistry, let alone the fact that most published formulas are only close approximations to the real thing and therefore while they may work with one film, they may not work with others. In addition, testing the results in image structure and color are quite difficult and usually people only eyeball their results. They usually make no direct comparison with the 'real thing'.

    PE

  6. #6

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    Gerald: the paranoia - I'd agree on that one. Now, I wonder how unhealthy tap water is, taking into account old piping systems... OK, thanks for the encouraging words. I'll keep hunting.

    PE: Thanks for the details, I had read similar posts of your's already. It would be great if you could specify which components need the accuracy, in particular which one needs the 1mg accuracy. I trust I can achive that accuracy in any case, but don't want to put in an effort where not needed - avoiding paranoia.

    While in general I would agree that accuracy is needed, I should state again that my main intention for mixing chemistry is curiosity as well as taking personal control and not a hypothetical _technical_ ideal. And in that sense I am perfectly happy to 'eyeball' my results but not only with a quick glance also with a magnifier, i.e. on the micro level.

    Whether, say in a portrait, the skin is a bit more warmer (yellow) or cooler (blue/olive cast) is not only a technical question but also an aesthetic one. Grainy (B&W and C) shots can look great or ugly. Look at lots of the fashion/lifestyle stuff - how off are colours there. Product photography uses lots of subtle lighting to create well pleasing images. Compare an image of a Big Brand Burger to the real thing.

    So, for me, if the results of any homebrew are optically pleasing on macro and micro level, I am happy. If not, I'll move on. Experience gained, lots learned. Just like I learned that most labs with professional control just don't give good results. But on them I have no influence. At home I have an influence. Even if not technically perfect, that is the kind of control I like to have.

    Guess I am saying the end justifies the means as well that I'm in it for the journey. But that only has validity for myself

  7. #7
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    Critical items are: The pH, iodide, bromide, color developing agent and sulfite. These are in order of importance high to low. The first 3 are critical.

    PE

  8. #8

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    Thanks for that. Would you take into consideration the water used for mixing? I.e. mineral content reflected in ph and oxygen content? I know our water here is really waky and surely will trip any mixture by more than 0.1. Sure, with a home brew I'd measure the grand total after mixing and then correct. But most 'consumer' C-41 kits never make a mention of it, never mind reminding to check/control the ph. Would that be more important in a home brew?

    As you mention that one chemical needs 1mg accuracy, I assume you refer to Iodine. The recipe I am looking at does not mention iodine at all only potassium iodide and that is in the blix. Do you mean that? It is used in a fairly small amount of 1.0g so 1mg would be 0.1% variation, not a big one, but alas, maybe relevant. Of course, you might have another recipe in mind actually using iodine. Or maybe the amount given (1g) is wrong anyhow.

    It would be great if you could share any more accurate information you might have, or at least point me to it, I could use to possibly use, to get better 'mixtures'. Unfortunately I have not found any information in the last weeks giving weights as, say 1.032g i.e. accurate to 1mg. The best I have seen is weights given to 0.1g implicating an accuracy of 100mg

    For that matter, it would be great to know, possibly before delving to deeply into my adventures or to better guide them, would deviations can I realistically expect, if say, the ph is of by 0.5 or even 1? Similarly with the (I assume) potassium iodide, if I am off by 0.1g?

    Maybe I am missing the obvious, but something I modify with 5 or 10cc when printing seems trivial to worry about. The (in-)accuracy of the aperture ring markings on the lenses, temperature (!) dependency of my spotmeter (never mind the inbuilt on) as well as their accuracy due to what-not and colour shift's due to daytime, clouds, humidity, etc. probably produce way more variance anyhow.

    But as said, it would be really great if you could give me some hints where I could find the information you base your knowledge on so I can do further reading myself. Possibly even a better C-41 recipe if you can spare one

    BTW don't get the idea I see self mixing as _the_ way to go. It's one of many ways. I like diversity and exploring.

  9. #9

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    Things like potassium iodide, that are used in very small amounts, are best made up as percentage solutions. One gram of potassium iodide in 1 liter of water would make a 0.1% solution. A typical E-6 developer would call for 30 ml of this solution in the second developer.

  10. #10

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    On reading my last post I find that I left out that a formula calling for 0.3 g (possibly hard to weigh out accurately) of potassium iodide would use 30 ml of a 0.1% solution.

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