Nova C41 powder 2 bath process

Discussion in 'Color: Film, Paper, and Chemistry' started by chorleyjeff, Oct 9, 2009.

  1. chorleyjeff

    chorleyjeff Member

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    Further to the thread on Tetenal and Fuji small volume C41 chemicals has anyone any experience of using the Nova equivalent and comments to make please?
    I have a dozen or so XP2 films to develop but don't want to get a 5 litre pack because depending on results I may well move on to conventional monochrome film.
    Cheers
    Jeff
     
  2. wclark5179

    wclark5179 Member

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  3. Photo Engineer

    Photo Engineer Subscriber

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    I do not recommend the powder kit for color negative. The blix, based on Sodium salts, will be too slow and ineffective for proper bleaching.

    PE
     
  4. Ian Grant

    Ian Grant Subscriber

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    This one uses an Ammonium Thiosulphate Blix, so may well be OK.

    The Tetenal C41 Press Kit also uses Ammonium based salts.

    Ian
     
    Last edited by a moderator: Oct 9, 2009
  5. chorleyjeff

    chorleyjeff Member

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  6. Photo Engineer

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    The Tetenal C41 Press Kit shown in the reference uses Sodium salts for both the Iron complex and for the Hypo. I have one here. That is what it says on the box.

    PE
     
  7. Ian Grant

    Ian Grant Subscriber

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    Strange, the Tetenal (Jobo US) MSDS shows the Blix as:

    Ingredients/Identity Information

    AMMONIUM FERRIC EDTA (25-50%)
    AMMONIUM THIOSULFATE (25-50%)
    SODIUM SULFITE (5-10%)

    It's a bit academic because I think Tetenal may have discontinued this kit some time ago, I may be wrong but I didn't see it on ther website last time I looked.

    Ian
     
  8. Photo Engineer

    Photo Engineer Subscriber

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    Ian;

    My apologies. The box does say that. My problem is that my private sources tell me that you cannot make solid powder Ammonium Ferric EDTA! It only comes as a solution much like most Ammonium Thiosulfate. In fact, the key patent is by Stephen and Surash if you wish to look it up. They show how it is made but don't (IIRC) mention that it could not be prepared as a solid. This was known though at EK.

    So, I assumed that this was in error. If you find that powder form Ammonium Ferric EDTA does indeed exist, please let me (and others) know.

    PE
     
  9. Ian Grant

    Ian Grant Subscriber

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    Will do.

    Ian
     
  10. pentaxuser

    pentaxuser Subscriber

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    Jeff I have used it for colour film and it seemed fine. The immediate problem is that you have to make up the whole kit at once and Nova gives a very short time period within which to use it all. If you have got enough films then this shouldn't be a problem. The longer term problem may be the longevity of film developed in powder. It depends on who you listen to. In terms of neg quality my prints from the negs seemed perfectly normal( no strange castes or strange and fluctuating filtrations needed) but I haven't tried to re-do any prints from the film and I cannot compare prints from negs done in the separate bleach and fix process as I have yet to try this process.

    If you like to do film in 1s, 2s or 3s,(i.e. small vols) and cannot get through enough film in Nova's recommended period then there is/was the alternative of Speedibrews C41 powder kits which are good for 4-8 films per pack. Martin Reed of Silverprint used to stock it and may still do. Powder is actually quite expensive compared to say the Fuji-Hunt kit which has separate bleach and fix steps. Cheapest seems to be from Ag Photographic at 29.99 ( Matt is a subscriber here) but does 60-80 films and maybe more.

    If I were solely a C41 person using exclusively colour neg and XP2 Super then this might be the way to go. MORCO does the Kodak kits albeit in large quantities but the expensive bleach should last and the fix and dev is relatively cheap and in the case of dev which has the shortest life it might be a case of being prepared to throw some away and replace.

    pentaxuser
     
  11. Photo Engineer

    Photo Engineer Subscriber

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    I have located a source of Ammonium Ferric EDTA powder here: http://www.newalliance.biz/prange.swf

    It is made to customer order/specification, and the data sheet says it is 85% pure (max?).

    So, this may change the landscape a bit regarding powder blixes. I have to do some calulations. It may turn out to be uneconomical or it may turn out that due to purity there is an issue. This does not change the picture regarding blixing of films, just the potential activity of powdered blixes and bleaches that use Ammonium Ferric EDTA.

    I did this while Ian was sleeping in Turkey. :smile:

    PE
     
  12. Ian Grant

    Ian Grant Subscriber

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    Photographers Formulary sell it, my old supplier (Rayco UK) sold it, I'd guess it's quite easy to source if you had a need for it.

    Ian
     
  13. Photo Engineer

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    Ian;

    The Formulary does not sell Ammonium Ferric EDTA in powder form. It is sold as the customary dilute solution prepared from Ferric Oxide, Ammonia and EDTA in special reactor to yield the dilute red solution we are familiar with. Working with this solution, you are limited in strength as to the Blix or Bleach you can prepare.

    PE
     
  14. Ian Grant

    Ian Grant Subscriber

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    Ron, sorry I hadn't checked the Formulary's website I'd made a note that it was an alternative source since Rayco closed up. I wonder if it's a difference in manufacture between US/Europe a bit like Sodium Bisulphite & Sodium Metabisulphite, or perhaps it's just availability.

    I don't think there's many people left who make up their own colour chemistry any more so demands probably very low.

    Ian
     
  15. Photo Engineer

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    Ian;

    There are several uses of Iron complexes with EDTA, but color photography is at the head of the list. Recently, with the introduction of NTA, the balance is shifting away from EDTA due to the higher BOD/COD of the latter and due to the "toxicity" of EDTA when in fact, EDTA is used intravenously in certain medical procedures (that being the secondary use of some of the complelxes).

    So, it is a rare beast just for color photography and it promises to get rarer and more expensive.

    Here is a scheme for making your own Ammonium Ferric EDTA. It should work. I have not made this in the lab for over 30 years though, so I'm writing this from old memory.

    Start with EDTA (the acid itself). Dissolve slowly in concentrated Ammonia solution (28%) until this is neutral and then add an equal molar (to the EDTA) quantity of Ferric Chloride. This will make a concentrate of Ammonium Ferric EDTA and Sodium Chloride in equal molar concentration. The pH should be about 6.5, never higher, and never lower than 4.0.

    If you go over about 6.5, you will precipitate Ferric Hydroxide which ruins the mixture and if you go below 4.0, the Ferric Ammonium EDTA will precipitate out. You will then have to make it alkaline and the dilution will decrease the strength of the concentrate.

    After you are done, add 1% excess of EDTA acid and readjust the pH. This last step is absolutely critical. If you omit it, you will cause severe stain in your photos. Iron salts will precipitate out in the film or paper and cannot!!!! be removed under normal circumstances.

    PE