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  1. #21

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    Quote Originally Posted by Athiril View Post


    When I'm doing non-experimental normal C41 development, I typically just use the same amount as you would normally.

    Normally its 3L + 1L + 1L, I use the same amount of chemical that would go into a blix bath.

    Eg instead of blix 180ml + 60ml + 60ml, I just use water 240ml + 60ml (for 35mm development, 300ml solution).

    So 1+4.

    I also save it in a bottle and re-use it, I thoroughly wash between baths so that I can re-use chems too.

    Though as with B&W dev, I've also used high dilutions and have just left it sitting there, agitating now and then, with no apparent difference to me.
    Just to be sure I have understood this. You are using bleach and fixer at 1+4 by using 60ml of bleach +240ml of water then 60ml of fix +240ml of water. Doesn't this alter the water to chemical ratio from that suggested by Tetenal in which it's 3 parts water to 2 parts chems(1 part bleach and 1 part fix).

    It has obviously worked for you but will this 1+4 dilution give the right ratios for long term film stability?

    My knowledge of C41 chemistry is far too poor to know if I have made a valid point or not.

    I have used the Tetenal kits in the past but have never seen any reference to making up separate bleach and fix kits. There may of course not be anything to be concerned about simply because Tetenal make no mention of the alternative of making two separate bleach and fix solutions. It might simply be that Tetenal do not share PE's concerns about blix or it regards the long term detriment to be so slight as to not be worth the extra time it takes for separate bleach and fix. After all one of its marketing slogans seem to be how short the blix time is.

    Anyway if for this purpose, we accept that bleach and fix is better, can you say how long you give bleach and fix processes?

    Secondly and I hope you don't mind me making this request, could PE comment on the point of correct dilution and what he regards as the correct bleach and fix times and how many times each diluted solution can be used.


    If I am to try mixing separate bleach and fix solutions then I need to be sure I do not make things worse by getting dilutions wrong or over using solutions.

    I hope you can appreciate my concern.

    Thanks

    pentaxuser

  2. #22

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    I agree with pentaxuser. I am just starting with c41 using some powdered unicolor kits, and I'd also like more info on the tetnal kit. I was just about to buy one of these kits, and like the idea of buying 80$ worth of chems at a time instead of 200$+!

    Cheers

  3. #23
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    Here is some information on powdered C-41 kits then!

    It is virtually impossible to build a dry bleach, fix or blix kit for film as the ammonium salts needed cannot be made easily and inexpensively in their dry form!

    Therefore, the kits are made from the sodium salts and are quite a bit less active than their comparable ammonium salts. They also have much reduced capacity! Watch out for the C-41 dry kits. You can do it with them in a bleach then fix, but you need a long time in the solutions to complete the action of bleaching and fixing.

    This is exactly the reason for abandoning sodium and solid kits for these processes. I remember demonstrating the first Kodak liquid blix kit for EP-2/3 for Paul Vittum in his newly refurbished office. He told me that the bottles better not leak or he would fire me! That was a joke on his part of course as the new carpet was green and clashed with the red blix. The purpose of the meeting was to describe the use of the new all ammonium solutions and to discuss the various patents for making Ammonium Ferric EDTA.

    Please see the patents by K. Stephen and J. Surash for more information. They may have gone into detail there, but IDK, I had their internal reports to go by and their talk to Vittum that same day!

    PE

  4. #24
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    Quote Originally Posted by pentaxuser View Post
    Just to be sure I have understood this. You are using bleach and fixer at 1+4 by using 60ml of bleach +240ml of water then 60ml of fix +240ml of water. Doesn't this alter the water to chemical ratio from that suggested by Tetenal in which it's 3 parts water to 2 parts chems(1 part bleach and 1 part fix).

    It has obviously worked for you but will this 1+4 dilution give the right ratios for long term film stability?

    My knowledge of C41 chemistry is far too poor to know if I have made a valid point or not.

    I have used the Tetenal kits in the past but have never seen any reference to making up separate bleach and fix kits. There may of course not be anything to be concerned about simply because Tetenal make no mention of the alternative of making two separate bleach and fix solutions. It might simply be that Tetenal do not share PE's concerns about blix or it regards the long term detriment to be so slight as to not be worth the extra time it takes for separate bleach and fix. After all one of its marketing slogans seem to be how short the blix time is.

    Anyway if for this purpose, we accept that bleach and fix is better, can you say how long you give bleach and fix processes?

    Secondly and I hope you don't mind me making this request, could PE comment on the point of correct dilution and what he regards as the correct bleach and fix times and how many times each diluted solution can be used.


    If I am to try mixing separate bleach and fix solutions then I need to be sure I do not make things worse by getting dilutions wrong or over using solutions.

    I hope you can appreciate my concern.

    Thanks

    pentaxuser
    Mine came as a totally liquid kit.

    I have used fix on much higher dilutions too.

    But the way I see it if you want to follow the normal directions is to just use the same amount of chemical per bath. IE: in the Blix bath if there is 60 ml of Fix and 60 ml of Bleach, use 60 ml of fix and 60 ml of bleach in separate bathes.

    Photo Engineer made the comment about them diluting each other, if so, then they are more active than when in a blix bath.

    AFAIK - A fixer's only job is to remove unexposed silver.

    C41 fixers are thiosulphate (rather than bisulphate like some B&W fixers) based - they take longer to fix than bisulphate fixers (ive tested a b&w bisulphate fixer and it doesnt seem to work on c41 film), so I can only see fixer ruining long term stability is if you had a high dilution and didnt leave it in long enough to do its job - and if you dont wash properly after the fix bath.

    Someone can correct me if I'm wrong here.


    edit: cant talk about the longetivity of my negs though..ive only had them for not long! and no way to artificially age.

  5. #25
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    Bisulfate is not used as a fixer. Thiosulfate is the fixing agent of choice in all fixers that I know of. Bisulfate may be an ingredient in some fixers.

    In a blix, a fixer can actually drive the bleaching reaction towards removing the silver image and so can assist if the blix is formulated correctly, but most blixes are not done correctly for film.

    PE

  6. #26

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    Thanks Athiril. My thoughts on the ratios are that to be on the safe side I might use 3 parts water to 1 part chems as per the Tetenal blix. In a Jobo 35mm tank and to make figures easy this would be 4Omls bleach or fix and 120mls water.

    Can anyone comment on how many times bleach and fix can be re-used and equally importantly is 40mls of bleach or fix sufficient per film. In theory it should be, as even if you mix the two full containers so it is 3L +1L +1L then when you use 140ml for a film the portions of bleach and fix are just as they would be at 40mls per Jobo tank.

    Finally what times for bleach and fix processing? My understanding is that neither can be overdone so safest might be the Kodak time which is what?

    Thanks

    pentaxuser

  7. #27

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    Someone asked about using Trebla chemicals. I have a pdf file from Stephen (Stephen Horton I believe) from CPAC imaging with product descriptions, dilutions, times, and temperatures for using their Trebla chemicals for one-shot processing in a phototherm processor. The file includes information for both E-6 and C-41.

    I imagine the instructions would likely work in other rotary processors as well.

    I will attempt to attach the file here.
    Attached Files

  8. #28
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    Quote Originally Posted by Photo Engineer View Post
    Bisulfate is not used as a fixer. Thiosulfate is the fixing agent of choice in all fixers that I know of. Bisulfate may be an ingredient in some fixers.

    In a blix, a fixer can actually drive the bleaching reaction towards removing the silver image and so can assist if the blix is formulated correctly, but most blixes are not done correctly for film.

    PE
    Tetenal Superfix Odourless is Sodium Metabisulfate though (and doesn't work at all on C41 films as a fixer when i tried it).


    Quote Originally Posted by pentaxuser View Post
    Thanks Athiril. My thoughts on the ratios are that to be on the safe side I might use 3 parts water to 1 part chems as per the Tetenal blix. In a Jobo 35mm tank and to make figures easy this would be 4Omls bleach or fix and 120mls water.

    Can anyone comment on how many times bleach and fix can be re-used and equally importantly is 40mls of bleach or fix sufficient per film. In theory it should be, as even if you mix the two full containers so it is 3L +1L +1L then when you use 140ml for a film the portions of bleach and fix are just as they would be at 40mls per Jobo tank.

    Finally what times for bleach and fix processing? My understanding is that neither can be overdone so safest might be the Kodak time which is what?

    Thanks

    pentaxuser
    Bleach and Fix can be re-used more on their own then they can mixed as a blix with the tetenal kit in my experience.

    You can over-fix, I read a thread somewhere that someone left some in some old fixer overnight, so we're talking in the vicinity of hours though, so as long as you dont forget that you left it in the solution, no you cant over do it.

    as for 1+3 ratio... it's actually 1+1+3, thus 60 mL of bleach and fix in a 300 mL solution, so I put 60 mL of active chemical to a solution for the bleach and fix bathes as the 'sure fire to work safely' amount. (ie tetenal blix solution is 60ml fix + 60ml bleach + 180ml water and i just separate that into their own bathes)

  9. #29
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    Athiril, Sodium Metabisulfate is not a fixing agent, I assure you. Sorry.

    It is known also as: 1,4-dihydrido-2,2,3,3-tetraoxido-1,4-dioxy-2,3-disulfy-[4]catena, 13455-20-4, 14970-71-9, 7631-94-9, bis(hydroxidodioxidosulfur)(S--S), CHEBI:29208, Disodium dithionate, DITHIONATE, Dithionic acid, Dithionic acid, disodium salt, H2S2O6, hypodisulfuric acid, NSC50070, Sodium dithionate, Sodium hyposulfate, Sodium metabisulfate, [(HO)(O)2SS(O)2(OH)]

    In water it normally decomposes into Sodium Sulfate and Sulfur Dioxide. It might be induced into decomposing into Sodium Hypo, and if so then that is the fixing agent.

    I doubt if that is the main ingredient and it is not intended as a fix under normal conditions. It is a rather rare chemical. I don't doubt that it could be present.

    PE

  10. #30

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    Quote Originally Posted by Photo Engineer View Post
    Thiosulfate is the fixing agent of choice in all fixers that I know of.
    Formula #126 in Anchell's Darkroom Cookbook, 2nd Edition is Defender 9-F Rapid Thiocyanate Fixer. This uses potassium thiocyanate as the fixing agent. The description says it works in very low temperatures, or in a matter of seconds at room temperature. This is a B&W fixer, though; I have no idea what it would do to C-41 film. I've never used it. I mention it mainly to see what you have to say about it, since I'm mildly curious about it. (I have no intention of using it, since Anchell says the thiocyanate is a skin irritant, and I prefer to keep my darkroom chemicals as innocuous as possible. I'm happy with the speed of the ammonium thiosulfate fixers I use.)



 

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