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  1. #1

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    Call for an internet compendium of color processing recipes and procedures

    More than one decade after both access to and page layout for the internet have become an uncomplicated way to gain and provide knowledge, the information on current color processing formulations (C-41, E-6, RA-4, and Ilfochrome dye-bleach) is surprisingly sporadic and anecdotal. With the replacement of film-based consumer photography by digital techniques, the overall volume and the turnover of commercial processing and chemicals, resp., may decline to a point where it becomes economically unsustainable. Many commercial photofinishing laboratories have closed, quality control is - as tests show - in severe danger of neglect, and processing times (with mailing) and prices may rise beyond practical acceptability, especially for amateurs. Fortunately, the current processes have been standardized decades ago and are applied by all (remaining) manufacturers of color photographic materials.

    Besides the information in books (which might, especially in science and engineering, be hard to find and expensive to buy even used) and, occasionally, in journals and magazines, there is presumably an abundant source of photographic process information in patent publications. Fortunately, such patents and patent applications are today available for free as printable PDF files (e. g. from the German patent office depatisnet.dpma.de recommendable for applications and patents from European countries, or from US sites such as freepatentsonline.com, patentstorm.us etc. for US patents and patent applications).

    As storage stability is much less an issue for amateur processing, where solutions will most likely be intended for single use, some of the reagents in the commercial formulations difficult or expensive to obtain may be replaced by standard chemicals. Furthermore, fresh solutions will avoid all the quality impairments of insufficient replenishment in commercial facilities. Using demineralized water, which should be readily available from hardware or drug stores in gallon/liter quantites, instead of tap water might avoid the need for exotic complexing agents or their excessive consumption - and will prevent the deposition of drying marks on the processed film.

    I would therefore suggest to build up an internet compendium providing color photographic recipes and procedures, which should be updated by the practical experiences of users so that finally a consensus formulation and procedure might ensure the consistent small-scale processing - at places where commercial laboratories are too far away or have become extinct.

  2. #2
    Ian Grant's Avatar
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    Used to be plenty in the British Journal of Photography Annuals each year.

    E3/E4, E6, C41, RA-4 etc, not many people want to make up their own colour chemistry its far more problematic than B&W.

    Ian

  3. #3

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    C-41 isn't that hard. The problem is you need to stock a bunch of chemicals. It's not like D-23 when you stock two items and make developer.

  4. #4
    Ian Grant's Avatar
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    Nick, none of them are hard it's just some of the chemicals aren't used in other formulae and you end up with a lot of surplus chemicals.

    Unlike B&W formulae it really is better to test each batch of home made Colour chemistry before critical use. A large professional lab in Birmingham, UK, Munns Brothers, always used to make up all its colour chemistry until they closed this lab in the 90's, (they own one of the major chains of processing stores & use Tetenal chemistry). It's easier with larger batches and when you have the correct monitoring equipment.

    When the Formulae/Recipe section here is finally finished it would be useful to have all the colour formulae listed, along with chemical suppliers.

    Ian



 

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