Kodak Monobath

Discussion in 'B&W: Film, Paper, Chemistry' started by Peter de Groot, Oct 9, 2013.

  1. Peter de Groot

    Peter de Groot Member

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    http://www.hofmeester.nl/Groups/Ron.../KODAK-MONOBAD-(6x500ml)-5087911-5087911.aspx

    See above link. I sometimes try new stuff. I played with teh monobath for a while that D. Qualls made up. Now I have some x-ray film i play around with and i stumbled upon this Kodak Monobath. Sorry for the link being dutch but I figured that the picture is cleu enough :whistling:
    But I have a hard time finding more information about this stuff. Can anybody help me out? I might try it out anyway as it ist not that expensive I think but any info is very welcome.

    Thanks.
     
  2. Ian Grant

    Ian Grant Subscriber

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    It's for dental x-ray film and it is a true monobath, how well it would work with conventional films I don't know. I did a lot of work on Monobaths in the late 1970's for work and had very good results but they need fine tuning to suit the material used to get the best results.

    Ian
     
  3. Peter de Groot

    Peter de Groot Member

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    Hi Ian thanks for your prompt reply. Since I have 18x24 cm x-ray film it might be worth a try. I will try it on normal film as well. And maybe I##l try it out on paper since x-ray film can be developped in paper developper as wel. You never know.
     
  4. Gerald C Koch

    Gerald C Koch Member

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    Ian hits on the most important problem with monobaths. They must be configured for a specific film and hence lack flexibility. Haist makes the same point in his book The Monobath Manual. Anyone interested in monobaths should get this book which contains a lot of useful and interesting chemistry.
     
  5. Ian Grant

    Ian Grant Subscriber

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    The Russians did a lot of work on Monobaths there was a long technical article in a 1970's BJP Annual which compared work on monobaths around the world inc Haist's work.

    Ilford used to sell a monobath for film processing - Monophen.

    Ian
     
  6. michael_r

    michael_r Subscriber

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    What I could never understand is why someone would have ever chosen to use a monobath unless the situation demanded it (spy developing film in a hotel room or something like that). No matter how optimized the formula is, a monobath is always a compromise, never ideal.
     
  7. TheToadMen

    TheToadMen Subscriber

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    Can someone please explain to me what makes a developer a "monobath"?
     
  8. michael_r

    michael_r Subscriber

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    Development and fixation occur in the same solution. So there is essentially one processing step (with a wash after).

    It is quite complex, but to (over)generalize, basically a high pH developing solution which also contains the fixing agent (silver halide solvent). The high pH is required so that development takes place very fast, before the thiosulfate dissolves the undeveloped silver halides.
     
    Last edited by a moderator: Oct 9, 2013
  9. Ian Grant

    Ian Grant Subscriber

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    It's a developer with fixer incorporated it develops faster than it fixes so you get normal negatives.


    If a monobath is optimised it can give results no different to a normal dev then fix sequence.

    The advantage is they aren't temperature dependent (over a reasonable range) and you process to finality. So there's no need for a thermometer or timer/clock.

    The big disadvantage is they really do need fine tuning for a specific film or paper and this is why they mainly get used for applied applications, such as this dental monobath. I worked on them for an industrial application and it was suggested we make one available commercially for paper processing.

    Ian
     
  10. michael_r

    michael_r Subscriber

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    I must have been editing while you were responding. I first realized the typo, then figured I'd add the paragraph but forgot to edit the reason for the edit!!! :D
     
  11. Gerald C Koch

    Gerald C Koch Member

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    Monobaths do find limited use in specialized applications, ie the Poloroid camera is based on a monobath. But for general purpose use they have no real advantage. A monobath depends on the control of two competing kinetic reactions; development and fixation. Unless the two processes are finely controlled the resultant images will be less than optimal. Monobaths became only practical with the use of Phenidone or its derivatives. The negative produced by a monbath differs from a conventional one in several ways. For those that are curious get Haist's book as he explains the differences fully. For example the image of a monobath negative is limited to the surface of the emulsion and does not penetrate very much into its interior. This acts to increase acutance.
     
  12. michael_r

    michael_r Subscriber

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    It is also quite grainy
     
  13. Prof_Pixel

    Prof_Pixel Member

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    "the Poloroid camera is based on a monobath" should say "the Poloroid B&W peel-apart system is based on a monobath"

    I know monobaths were used in some early B&W reconnaissance satellites.
     
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  15. Vaughn

    Vaughn Subscriber

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    I guess Polaroid Type 55 was the exception...the negs are beatutiful!
     
  16. Peter de Groot

    Peter de Groot Member

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    But no one has actually experience with the Kodak Monobath? As my question was?:whistling: I don't mind the talking that was going on. But I geuss I will have to buy 6 bottles of 500ml and give it a try. See how it behaves and such.

    My interest is purely curiosity. Do it once or twice and probably forget about it. But it would be nice to go out on a trip with Harman direct positive paper and be able to process it on the spot on step. Not that I have any specific plans yet :smile:
     
  17. Ian Grant

    Ian Grant Subscriber

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    Neville Maude's article "The Rise & Fall of the Monobath" in the BJP Annual (can't remember off hand if it was 1972 or 76) states that the US research was sponsored by the US Air force and they were working with 40" wide film. H.S. Keeling an was using Phenidone based PQ monobaths as soon as it was commercially available in the early 1950's.

    In the UK a commercial monobath "Develofix" was available and reviewed in 1913 by the BJP. Mees and Sheppard a pair of chemists in the UK just out of University worked on Monobaths they pointed out that development was deep in the emulsion but that the effects of the solvent (thiosulphate) were greatest at the surface.

    I've a around 30+ pages of notes on Monobaths as well as quite a few Patents and articles and it would be useful to collate it all, unfortunately I have little time at the moment as I've just moved house and much of my stuff is in storage.

    As Vaughn points out Monobaths are capable of excellent fine grain and sharpness, and my experience is with the balance right there's no loss in Dmax.

    Ian
     
  18. Prof_Pixel

    Prof_Pixel Member

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    I remember using (and selling) a monobath in the late '50s or early '60s. Seems to me it was called Unibath. It worked OK, but the shelf life was short.
     
  19. Ian Grant

    Ian Grant Subscriber

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    Unibath CC1 (normal films), CC2 (high speed films slight push) and CC3 (papers) :D Introduced 1959. by the Cormac Corporation of New York. Evidently the CC3 was useless with British papers and was unsuccessful. (It's in my notes)

    Ian
     
  20. AgX

    AgX Member

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    All diffusion transfer-reversal systems based on silver-salt use monobath processing. This includes the former Polaroid integral b&w system.
     
  21. Prof_Pixel

    Prof_Pixel Member

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    Interesting enough, it doesn't apply to the integral picture unit Kodak Instant/Fuji Instax films

    I don't remember ever seeing an integral picture unit B&W film from Polaroid.
     
  22. AgX

    AgX Member

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    It was marketed for some years. Impossible tries to make us believe they were the first to market b&w integral instant film, as that Polaroid film is merely known.
     
  23. nworth

    nworth Subscriber

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    I'm not quite sure where this came from:

    Kodak monobath film developer-fixer (1961)
    Sodium sulfite 50 g
    Phenidone 4 g
    Hydroquinone 12 g
    Sodium thiosulfate (penta) 110 g
    Sodium hydroxide 4 g
    Develop film 4 - 7 minutes at 23C (or until fully fixed)
    To mix, add the Phenidone to the water, but do not mix. Add a pinch of the hydroquinone. Add the remaining ingredients in the order given, and mix to dissolve the Phenidone. Then add the remaining hydroquinone. Dissolve the sodium hydroxide separately in a small volume of water before adding it to the mix.
     
  24. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I was working with monobaths for a while and occasionally come back to it as circumstances demand it. The attraction at the time was to be able to process film in limited space with fewer trays, storage bottles, etc. Another attraction might be to process sheet film with less handling, say one sheet of ULF at a time.

    In fact the results were quite good, and if you like the Type 55 look, a slow to medium speed traditional film (I was fond of Efke PL100) in a monobath (I was using mainly fx6a) is kind of it. Haist argues that you can tweak a monobath to give results similar to D-76, and that fits with my experience.

    The problem with a monobath is that without exotic and expensive chemicals, it tends to self-destruct once you start using it, so you have to mix it up and use it in one session, or at most within two days, or fixed out silver, the fixer, and the developer all start interacting to produce sludge and to exhaust the developer. You also need kind of a lot of developing agent to compete with the fixer, so it could get costly in large quantities.

    There's a long monobath thread around here with lots of formulas, info, and sample images.
     
  25. Peter de Groot

    Peter de Groot Member

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    Hi David thanks for the info. I know that there is a long thread about monobath. But my question was really if anyone has more info on the Kodak monobath that is sold for use with x-ray film. And if anyone has some hands on experience with the stuff. No answer yet :smile:
     
  26. Ian Grant

    Ian Grant Subscriber

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    Grant Haist MM-1


    It's Grant Haist's NN-1 formula. It can contain Gluteraldehyde 25% 8ml (hardener) to prevent softening of the emulsion.


    Grant Haist's Monobath MM-1

    Sodium Sulphite (Anhyd) 50.0g
    Hydroquinone 12.0g
    Phenidone 4.0g
    Sodium Hydroxide 4.0g
    Sodium Thiosulphate 110.0g
    Gluteraldehyde 25% 8ml
    Water to 1 litre

    Do not dilute for use.
    Process for 6 min's at 20c. Agitation for first 30 seconds then 15 sec's every minute on the minute. To adjust the contrast use greater or lesser amounts of Hypo. Use of more will result in a softer image, less increases contrast.

    Ian