Paterson orbital processor

Discussion in 'B&W: Film, Paper, Chemistry' started by pauldc, Oct 11, 2005.

  1. pauldc

    pauldc Member

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    Hi, anyone out there using the Paterson orbital processor for 5x4 and 8x10 black and white film? I have just bought one but don't have the motor base and wondered what speed I should rotate the unit by hand. How fast does the motor base do it - I am guessing several revolutions per minute but it would be really helpful to know.

    Cheers

    Paul
     
  2. Dave Miller

    Dave Miller Member

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    The motorised base doesn’t rotate the dish, it rocks it in a circular motion at about 2 a minute. I’ve used mine for 5x4 with good results. I put beads of slow drying epoxy glue over the base so that the chemicals can get underneath the negatives, and make it easier to remove the wet negs.
     
  3. waynecrider

    waynecrider Member

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    For intermittent agitation you can fill it to cover the neg and rock it back and forth by hand, carefully. Never a problem if the inside base is roughened up so the negs don't stick. I used sandpaper and scored with a utility knife. You can use it in a water bath for temp control.
     
  4. bev

    bev Member

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    Yes about 2 - 3 revs per minute.
    Rather than 'do things' to the base I used two strips of slightly folded old film across the base, secured by the red pins.
    Always put the film in emulsion side up of course.
    Dev times for continuous agitation have to be a bit shorter with the motor, but are very reproducible, and very economic with developer.
     
  5. chiefstoker

    chiefstoker Member

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    Motorsed drive on paterson orbital

    My advice is 'Don't use the motor drive'.
    With more than 150ml of solution it is unstable and rotation is jerky. accompanied by 'bathtub' waves. If using less than 200 ml of most dilutions,say D76 1:1, there may not be sufficient developer agents to give optimum results. Observe the flow pattern over the surface of the negative(s)when using small quantities of fluid: you will see it gives copious agitation at the corners with less at the centre, promoting uneven development. Agitation by hand is a simulation of tank inversion agitation; five seconds every half minute for similar times. I use 'Four tilts' in five seconds, twice a minute, in a 'North, East, South, West' sequence, varying the start direction, and sequence, at each half minute.
     
  6. Dave Miller

    Dave Miller Member

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    The recommended amount of fluid is, I think, around 60ml. This is more than enough to develope 4 sheets of 5"x4" film. Putting more fluid is is simply wastful.
     
  7. pauldc

    pauldc Member

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    Is it not a problem with such little volume of developer to have enough to meet the minimum quantity recommended by the manufacturer. I commonly use rodinal at 1:50 for Efke 100. As I understand it I would need atleast 510ml of developer solution to ensure I use the minimum of 10ml of Rodinal or can I in reality get away with far less? If I was to use, say, 60ml total developer solution then this would only contain 1.17ml of Rodinal. Would be great for my wallet but is it possible?

    Many thanks.
     
  8. Dave Miller

    Dave Miller Member

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    The reason we use so much fluid in a standard tank is to cover the film. We only need 60ml in to do this in the orbital processor. I have used Ilford Ilfotec DD-X with 4 sheets of Ilford FP4+ without any problem. I had similar doubts to yours so started by developing just one sheet, then two, and finally four sheets when I was confident that it worked.
     
  9. pauldc

    pauldc Member

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    Thanks Dave, I will give it a go tomorrow and report back on my results.
     
  10. pauldc

    pauldc Member

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    Well, this morning (when I should have been working), I used 100ml of water with 2ml of Rodinal to make the ratio of 1:50 and the negative came out great. I used 9.5 minutes of continous agitation (film was efke 100). I am happy!
    Thanks everyone
     
  11. marktweedie

    marktweedie Member

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    I just got round to experimenting with the orbital processor + motor drive using 60ml Prescysol at standard dilution for 8mins. Most results were excellent and this appears to be a really easy way of deving sheet film compared to trays/tubes, however, on one or two negs in areas of open tone (ZVI - ZVII) there is a strange mottling. Have you experienced this, Dave? My thinking is that 60ml of developer contains too little active agent for 4 sheets of 5x4 and results in uneven development. I used 1ml A, 3ml B, 56ml distilled water and presoaked for 5mins at 24 degrees C.

    Though, thinking this through as I write, it seems I have miscalculated the proportions slightly for the total quantity. Maybe the excess proportion of solution A has had an adverse effect? Could incorrect temperature have a similar effect? Must check my thermometer.

    Mark
     
  12. Peter Black

    Peter Black Subscriber

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    Hi Mark
    No experience of Prescysol so can't comment on that aspect. I've used the Paterson Orbital & motor with both Rodinal and CM Pyro, but the big drawback with the orbital is always going to be the small quantities of developer and the accuracy needed for repeatable results. If you are using syringes then 1 or 2ml is OK, but any other way is making it hard to get accuracy between say 1.75 and 2.25 if you're actually trying for 2ml.

    I agree with Dave that 55 or 60ml should be enough, but having tried the orbital with the lid off during washing, 100ml is not an unreasonable amount and will not spill even with the lid off, so should be perfectly fine for processing with the lid on. Hey, if we're bothered about the cost difference between 1 and 2ml of Rodinal / other developer then we're in the wrong game!

    I've never had uneven development with the orbital, so can't help on the mottlling aspect, but think it is worthwhile persevering with the technique.
     
  13. marktweedie

    marktweedie Member

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    Thanks Peter, my plan was to double the quantities of developer which will also allow me to use the solutions up before they expire (not a problem with Rodinal, I know). There are other recommendations in this thread not to use the motor base so I will try to isolate the problem and, I hope, continue to use it as 8 minutes of continuous hand agitation is tedious to say the least!

    Mark
     
  14. Dave Miller

    Dave Miller Member

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    Why anyone should recommend that the motor base is not used is a mystery to me, after all it’s designed as an aid to consistent development.
    If you feel that there is insufficient active chemical in the mix / quantity then why not develop one sheet and check your results with that first. If it is satisfactory, then go to two sheets at a time, and so on. You can certainly increase the fluid volume if you wish, probably up to 180ml, and still leave room for the chemicals to churn. With regard to temperature I develop in ambient temperature, which in my darkroom is about 20 to 22ºC without ill effect, but accept that it is always better to be consistent.
     
  15. marktweedie

    marktweedie Member

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    Thanks for the suggestion Dave, I will certainly do some testing. I, too, struggle to process at a consistent 24ºC. Given that dilution is the thing with Prescysol I will probably start to process at 20ºC or thereabouts as I can easily maintain that consistently.
    Regards, Mark