C41 Bleach Formula?

Discussion in 'Color: Film, Paper, and Chemistry' started by Peter De Smidt, Oct 9, 2005.

  1. Peter De Smidt

    Peter De Smidt Member

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    I've started processing c41 at home with Kodak Flexicolor chemicals. So far so good, but it's very expensive. Bleach costs me the most. Does anyone have a good formula for C-41 bleach?
     
  2. Photo Engineer

    Photo Engineer Subscriber

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    Yeah, but guess what? Its expensive.

    The Ammonium Ferric EDTA is what is going to cost you the most. You cannot easily get the Ammonium Ferric PDTA that Kodak is using in the newest bleach.

    If someone tries to pass off to you a Ferricyanide bleach, remember that it is cost effective, but you need a wash and clearing bath after the color developer and before that type of bleach or you will cause a lot of stain, and you need to wash well before you go into the fix.

    So, here goes:

    Ammonium Ferric EDTA solution (50 - 60%) 200 ml
    Ammonium Bromide 150 g
    Disodium EDTA 10 g
    Ammonium Sulfite 10 g

    Dissolve in 500 ml water and bring to 1 liter. Adjust pH to 6.5 with 28% acetic acid.

    This is a slower bleach than the new RA Bleach III, so use it for about 6 minutes at 100 F. If you want that faster bleach, then substitute Ferric Ammonium PDTA for the EDTA. PDTA is 1, 3 propylene diamine tetra acetic acid. I have the figures for that as well, but it is hard to get and rather counter productive if you want to save money.

    PE
     
  3. Peter De Smidt

    Peter De Smidt Member

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    Ammonium Ferric EDTA solution (50 - 60%) 200 ml
    Ammonium Bromide 150 g
    Disodium EDTA 10 g
    Ammonium Sulfite 10 g

    Thanks for the formula! JD Photochem has the Ammonium Ferric EDTA solution (50%) for $19 a liter, Ammonium Bromide for $10 a lbs., Disodium EDTA for $15 a pound, and they don't carry ammonium sulfite. So roughly this mixture is $4 a liter plus shipping. I think that I paid $9/L plus shipping for the Kodak product. Maybe some of the chemicals can be found for less.

    Kodak says to use all the solutions one-shot in a Jobo. Is this really true from the bleach and fixer?
     
  4. srs5694

    srs5694 Member

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    Does anybody know offhand if JD Photochem ships to the US? I ask because the usual US photochemistry hobby suppliers (Art Craft, Photographer's Formulary, etc.) either don't carry ammonium bromide or charge much more for it than the $10/pound quoted here -- on the order of $20-$40 for 100 grams (~$90-$180/pound). Alternatively, does anybody have a more reasonably priced US source for ammonium bromide? Also, what about ammonium sulfite? The usual suppliers don't seem to carry that, although some do have ammonium sulfate. (Could that have been a typo, PE?)

    FWIW, I've also recently begun doing my own color processing. So far I've tried one mix-it-yourself blix, which produced overly grainy negatives, and the Paterson Photocolor blix. The latter works much better than the home-mixed blix and is much less expensive than the Kodak chemicals, but given what I've been hearing about blixes, it might not work as well as separate bleach and fix. Still, it might be worth at least trying it if you can't put anything else together. B&H carries the Paterson chemistry.

    If you're interested, here's the site with the home-mixed blix formula I tried, but as I said, I can't really recommend that formula. They've also got a ferricyanide bleach formula (80g potassium ferricyanide and 20g potassium bromide in water to make 1l). I've not tried it, though, in part because from what I understand, potassium ferricyanide is no longer used in commercial bleaches for environmental reasons, and I don't want to bypass environmental concerns. If this information is wrong, though, I might give that formula a try, keeping PE's processing procedure caveats in mind.
     
  5. OldBikerPete

    OldBikerPete Member

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    garbage
     
  6. OldBikerPete

    OldBikerPete Member

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    Sorry, sorry - I didn't mean that your post was garbage, I was trying to post a response and I was getting a web page error. In the process of poking around trying to get something to work, guess what?:surprised:
     
  7. OldBikerPete

    OldBikerPete Member

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    This is the response I was trying to make when I posted "garbage".
    How important is the Ammonium component of this recipe?

    I mean if one were to replace NH4Br with KBr or NaBr and (NH4)2.SO3 with Na2SO3 or K2SO3 and adjust the quantities to maintain the same concentrations of Br and SO3 in solution, what would be the effect/s other than a tendency to buffer at different pH before correction with acetic acid (or -say- Na2CO3)?
     
  8. Photo Engineer

    Photo Engineer Subscriber

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    You can replace the ammonium sulfite with an equal weight of sodium sulfite, but you cannot replace the ammonium bromide with sodium bromide or it will be VERY slow to bleach. For the purists the ratio of the molecular weights of ammonium to sodium are virtually unimportant for these purposes.

    You can use EDTA acid and neutralize it with ammonia as well rather than use disodium EDTA. There are many ways to do this.

    All bleaching in this is based on a mutual reaction of ammonium ion, bromide ion and ferric EDTA (or PDTA). If you put in too much sodium ion, the bleach slows down to a crawl. Keep the sodium ion at a minimum and if you overshoot in pH adjust, going too acid, don't use sodium hydroxide, use ammonium hydroxide to go back up in pH.

    You can get ammonium sulfite from the Formulary by special order (I think) or from ANTEC (kyantec.com).

    Avoid all potassium ions like the plague in both the bleach and fix.

    Film blixes have a great tendancy to cause silver retention with associated higher grain and blocked highlights in the print. They are often less stable than bleach then fix processes. There are blix formulas. I am working on one right now that should solve these problems.

    PE
     
  9. Nick Zentena

    Nick Zentena Member

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    JD will ship any place. Certainly to the US. Notice the prices are in US $.

    But to save money on bleach and fix you might want to consider buying bigger bottles. The bigger the bottle the less per litre. Plus aren't you supposed to mix oxygen into the bleach?

    I replenish bleach and fix.
     
  10. Peter De Smidt

    Peter De Smidt Member

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    Hi Nick. Do you use a Jobo? If so, what chemistry do you use?

    I don't really understand why Kodak recommends using the bleach only once in a Jobo, since bleach actually needs lots of oxygen to work properly. (I can see why the increased oxygenation (right word? I'm not a chemist) can cause problems for developer and to a lesser extent to fixer, but bleach?) I'm thinking of using the replenishment scheme that Kodak recommends for non-rotary systems. That would quadruple, or so, the amount of use that I'd get out of the bleach.

    What about fixer? Can I use it until Edwal Hypo Check says otherwise?
     
  11. Mick Fagan

    Mick Fagan Subscriber

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    In the Kodak C41 processing manual that I have, it's stated near the end of the bleach section, that bleach has an indefinite life.

    I myself have used a bleach regeneration process from Creative Darkroom & Photo techniques, since it was published in that magazine.

    I originally mixed up a litre of bleach and after usage I rehalogenate the bleach with a fish tank aerator for about 20 minutes or so. Then I re-adjust the pH using a small amount of acetic acid and it's ready to go again.

    After a while, one loses a bit of solution through natural attrition so I just mix up about 250ml of bleach and I'm off again.

    I've been doing this for years, it makes C41 so cheap to do this way.

    One of the things I did do after some experimentation was to use a weak stop bath after development. The idea is to stop development at a precise time, enabling one to then give the film a short 30 second wash after the stop before adding the bleach. This has had no visible effect on the films but has reduced the bleach requiring a pH adjustment by about 50% on a number of films put through the bleach before adjustment is required.

    I rotary process with a Jobo and lift.

    Mick.
     
  12. Nick Zentena

    Nick Zentena Member

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    I'm using Jobo 2500 type tanks but on a motorbase. The only difference I can think of is the speed the tank spins. But I doubt that matters enough.

    For C-41 I'm using Fuji mini-lab chemicals. I just repenish according to the Fuji specs. For both fix and bleach.
     
  13. Peter De Smidt

    Peter De Smidt Member

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    Nick, where do you get the Fuji-Hunt mini-lab chemicals from?
     
  14. Peter De Smidt

    Peter De Smidt Member

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    Hi Mick, I appreciate your experience.

    Currently, Kodak says that their bleach has an 8 week life; and they say, in bold no less, "Do not attempt to replenish or regenerate used bleach solution. Reuse it only to batch capacity [which they elsewhere state to be about 4 120 films per liter]; then discard it. Also, do not reuse developr, fixer, or stabilizer. You must discard these solutions after a single use." This is from the current PDF on using Flexicolor chemicals with rotary-tube processors. I wish they'd tell use what their reasoning was. Clearly with developers the problem is excess oxygen introduction during processing.
     
  15. Nick Zentena

    Nick Zentena Member

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    One of the local labs got a new machine. The new machine uses some sort of pre-packaged chemicals. I was in and he offered me the old stock. I offered 1/2 and he jumped up and down all happy. I was happy to-)

    Vistek locally carries the Fuji chemicals. Odds are somebody locally carries the stuff. Lots of mini-labs need it. Maybe if you know anybody running/working at a mini-lab you could ask if they'll order a jug for you?
     
  16. gbroadbridge

    gbroadbridge Member

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    Do some tests yourself. I think that the fear is of some contamination affecting the solution, not the life of the solution itself.

    Graham
     
  17. Peter De Smidt

    Peter De Smidt Member

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    I just talked with Kodak's technical department. They say that the problem with replenishing bleach with rotary tube processing is the small amount of solution used. They recommend only 6- 120 films per liter. The problem, said Tony, is retained silver. Comments?
     
  18. Nick Zentena

    Nick Zentena Member

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    Since I reuse bleach and fix I only use the minimal amount of chemicals for developer. I think I've got 2litres of fix made and 1litre of bleach. When I process I use what I need then pour it back. Replenish the big bottle.
     
  19. Photo Engineer

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    The bleach uses up the bromide, so aeration alone is not going to regenerate the bleach. It gradually loses activity through loss of bromide. It must be aerated and then fresh NH4Br must be added (ammonium bromide).

    The fix gradually is oxidized by the carryover of bleach into it unless you do a very thorough wash after the bleach and before the fix.

    Gradual build up of carryover fix into the stabilzer can cause dye stability problems.

    Drum processes are notorious for gradual carry over of one solution into another and this causes dilution and degradation of the chemistry.

    Since a pre-wet is recommended (or used to be by Jobo and Kodak both), the developer was diluted by the pre-wet and this was compounded if you reused the developer over and over. Also, there are seasoning effects in the developer due to released iodide and bromide. It is always best to discard the developer.

    So, in short, use developer one time and toss, use bleach till exhausted then aerate and replenish with some fresh or add NH4Br. I removed 100 ml and add 100 ml of fresh to each 1 L when I reach capacity.

    I do the same for my fix. Use to capacity, then remove 100 ml from 1 L and replenish.

    I use my stab and toss generally, but I have extended my wash to 2x and used the stab until it is exhausted, then replenished as above, 100 ml / liter.

    PE
     
  20. Peter De Smidt

    Peter De Smidt Member

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    PE,

    Thanks for your help. Kodak says (in their pdf on Flexicolor in a rotary processor) that one shouldn't use a pre-wet.

    BTW., what types of problems would retained silver cause? I'm not sure if Tony at Kodak meant retained silver in the emulsion or retained silver in the chemistry.
     
  21. Photo Engineer

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    A pre-wet is advised to temper the drum and film to 100 F. It causes no problem and helps a lot. I have run lots of film this way for over 20 years. It works.

    Retained silver in the film causes muddy color in prints, higher grain, blocked highlights, and sometimes crossover. Retained or excess silver in the chemistry causes retained silver in the film so it causes the same problem in the end.

    Remember that you can have retained silver metal and retained silver halide depending on where the silver retention problem takes place. The retained silver halide will gradually darken causing dmin to go up and shadows to become compressed with odd color crossovers. The retained silver metal is mostly retained in dark areas in the negatives which cause the highlights to become compressed and odd color crossovers. Grain can go up at either end depending on the type of retention.

    PE
     
  22. Mick Fagan

    Mick Fagan Subscriber

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    To PE you have answered the questions that were asked of me, which is good as I wouldn't have been able to answer a technical question as well as you have. I will also check out my regenerating of the bleach system and maybe upgrade it a bit.

    I do have a query though on pre-wetting film and paper. For some years I was regularly pre-wetting both films and colour paper (EP2) then one summer I started getting Cyan streaks on the prints.

    As I was at the time using Agfa chemicals I contacted them and their chemist immediately asked me if I was using a pre-wash for my prints, which I replied that I was. His next statement made me re-think about pre-wetting.

    Basically he advised that we were in late summer, the dams were quite low and as a result of that, the water authorities added a flocculant to the water to make the precipitates drop. This gave them an easier chance to engineer clearer drinking water. However this flocculant also had a side effect on unprocessed colour paper.

    The advice was to resist a pre-wet in both paper and film developing as it isn't required if the system is up to temperature. I stopped pre-wetting then and there, and haven't looked back since. I still have a piece of a print on the darkroom wall showing this cyan streaking caused by the said flocculant.

    Since then I have gone over to roller transport paper processing and it doesn't worry me about paper, but I certainly do not pre-wet my films, either B&W of colour.

    Mick.
     
  23. gbroadbridge

    gbroadbridge Member

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    PE, I temper the drum and film dry, and it's never caused me a problem. They both get up to 100F in 10 mins or so.

    I'm not questioning your expertise (you are without a doubt one of APUG's most important contributors) but have you tried without the tempering wet bath?

    Graham
     
  24. Photo Engineer

    Photo Engineer Subscriber

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    To Mick and Gbroadbridge, here are some hints.

    Papers contain high chloride emulsions. As such, they are senstive to chlorine and other halides and some chemicals used in water treatment. However, the manufacturers know that and engineer their papers (or should) to avoid that very problem. I have never observed that problem with any variant of Kodak papers. I have never heard of it with Fuji papers. Agfa papers have been such a small runner that I am not familiar with their response.

    I use a pre-wet all the time.

    Early instructions from Kodak and Jobo among others recommended a prewet. I have found that I get uniformity problems in both paper and film without one, and sometimes get variable results along with air bells due to bubbles. So, I find it a plus.

    Now, as for cyan streaks. I have found that the most usual cause of cyan streaks is due to insufficient stop action after developing RA paper, particularly at high temperatures. If I use a stop, I never get the streaks, but if I omit it, I get streaks. This is due to fixation and development taking place side-by-side at the same time in that hot drum.

    Here is my process:

    Prewet 100 F 45"
    Develop RA-RT Repl 45" - 1' Depending
    Stop 30"
    Blix 1'30"
    Wash 2'
    Dry

    My C41 process is the EK process with two 30" 100F prewet stages.

    Thank you for the nice comment. I try to help here as much as possible drawing on my experience in product and emulsion development work at EK.

    My warmest regards to everyone who has shown an interest in this. Please feel free to contact me personally with questions. Some people seem to feel reluctant. I really don't mind at all. I keep busy on these cold rainy (soon to be very snowy) Rochester days answering mail and chatting or working in the DR.

    PE