peeling rc paper for paper negative

Discussion in 'Paper Negatives' started by Akki14, Aug 10, 2007.

  1. Akki14

    Akki14 Member

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    I've heard mumbling of somehow peeling the emulsion off of RC paper to make a more see-through paper negative for contact printing... Does anyone here do this? What's your method for soaking the paper and is there anything to speed up the process?
     
  2. Ria

    Ria Member

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    I have done this a few times by just soaking the paper in water a very long time and then s-l-o-w-l-y peeling the emulsion off the paper. It worked very well for my purposes. I don't know of a way of expediting it. The main problem I had with using the resulting backing-free-emulsion negative was its insistence on curling.
    Ria
     
  3. Akki14

    Akki14 Member

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    I use lucky film sometimes for my contact prints on cyanotype - I know the problems of curly negs! I don't mind though, especially if it's an affordable way of making large negatives.
     
  4. keithwms

    keithwms Member

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    I guess my question would be: why??

    If you weigh down the paper neg on the receiving paper during contact printing- I use a heavy, half inch thick chunk of glass- the result will be surprisingly sharp.

    If that doesn't suffice, then I suppose that the paper could be waxed on the back. That might reduce the effect of the paper texture (though honestly I like that texture)

    Both of those options strike me as easier than peeling off the emulsion.

    Also, peeling off the emulsion would defeat one of the nicest purposes of a paper neg: you can work at a light table and retouch your neg on the back side with a pencil, erasing if you make blooper. It's fun for the whole family.

    Having said that, if you get it to work please let me know, I am always game to learn new tricks!
     
  5. Akki14

    Akki14 Member

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    I tried with cyanotype paper today and the results weren't so sharp. It's probably because cyanotype works based on shadows more than on anything as fast as silver gelatin paper which reacts to any light not just mostly-UV light. I use a proper contact printing frame so I'm definitely getting good contact between paper and paper.
     
  6. Dave Miller

    Dave Miller Member

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    A few observations because I've never tried to split a print like this.
    Surely R/C paper would need to be soaked for a very long time because it is specifically designed to keep water out?
    For the same reason I doubt that waxing the back would have much effect, certainly not to the extent that it does with fibre paper.
    Printing with the emulsion side in contact with the receiving paper achieves maximum sharpness.
    The only benefit of pealing a paper would be to reduce the exposure time slightly, and I question if it would be worthwhile.
     
  7. Akki14

    Akki14 Member

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    Nonpeeled paper took 2-3hour exposure to 100% sunshine yesterday. And I was contacting emulsionside down against the coated paper so I'm not sure why it looks slightly blurry.
     
  8. Dave Miller

    Dave Miller Member

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    I'm beginning to see your problem, with the English sun.:smile: The method generally employed with paper negatives is to rub paraffin wax, or similar, into the back of the print to render the paper translucent, but as I wrote earlier I don't think that will work with r/c paper.
     
  9. Schlapp

    Schlapp Member

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    Try doing it under a tungston lamp. And put a heavy piece of glass over them to hold them together. Using an enlarger lamp, my exposures through RC paper are around 30 secs to 1 min.
     
  10. Dave Miller

    Dave Miller Member

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    That's a thought Schlapp, I had assumed that Akki14 was trying to print one of the alternative processes that demands UV rich light.
     
  11. Akki14

    Akki14 Member

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    I am using alt process - cyanotype. Even my facial tanner which is a nice bank of UV bulbs takes a while to contact print normal film (30min-1hr vs sunshine 8-15minutes depending on neg density - 28minutes tops for the really dense negs)
     
  12. keithwms

    keithwms Member

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    Hmm, UV transmission through RC paper is probably going to be pretty lousy.

    Say, can you make a wet contact print? In other words, wet the neg and the print paper with plain water, sandwich them between glass, and then expose? If you squeegee out the bubbles then you may (I repeat may!) see some sharpness and exposure benefits. I am thinking that the water may increase the UV transmission of the paper. (I use plain water with immersion objectives in my UV microscopy)
     
  13. Akki14

    Akki14 Member

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    No, because water is used to wash away the undeveloped portions of cyanotype so water + unexposed paper = nothing.

    So basically I can't use paper as a good replacement for enlarged negatives. Darn.
     
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  15. Schlapp

    Schlapp Member

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  16. keithwms

    keithwms Member

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    ah okay.

    But I think you can wax the back of the rc paper, I vaguely recall reading that somewhere.
     
  17. Photo Engineer

    Photo Engineer Subscriber

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    It is an interesting side note that the early RC papers would delaminate in a long wash and a lot of work went into keeping it from being peeled apart. It seems ironic to me that you are now wanting to circumvent all of this to peel it apart.

    BTW, AFAIK, waxing will not work on RC, but can on some FB papers.

    PE
     
  18. Akki14

    Akki14 Member

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    Would it work if I peeled it in half and waxed what remained of the paper? I was going to try a peeled in half RC paper today but I've been busy with chores and stuff.
     
  19. Photo Engineer

    Photo Engineer Subscriber

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    I'm really not sure if that would work due to the structure of the support when compared to FB.

    Sorry I can't help. I am fairly sure that waxing the unpeeled paper will not work from what I remember.

    PE
     
  20. Ray Heath

    Ray Heath Restricted Access

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    g'day all

    PE, i'd expect this would work as the wax or oil can't penetrate the RC but would be absorbed into the paper fibres once the plastic is removed

    i regularly use baby oil on FB
     
  21. Photo Engineer

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    Ray;

    He is talking about unpeeled papers which requires that the wax penetrate 2 layers of poly ethylene. This might not work. I have been told it would not.

    If stripped, then it might penetrate to some extent.

    I would agree that baby oil might be better than wax. It works on FB, but don't forget that PE is quite resistant to penetration even by baby oil.

    PE
     
  22. Dave Miller

    Dave Miller Member

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    Akki14, it seems you should consider using fibre base paper,single weight if you can get it.
     
  23. Loris Medici

    Loris Medici Member

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    Hi Akki14.

    During the long exposure, have you moved the frame from time to time - in order to maintain the angle of incidence? Sun will take a long way in the sky in 2-3 hours, changing the angle of incidence considerably and giving you an effect similar to motion blur.

    Regards,
    Loris.
     
  24. Akki14

    Akki14 Member

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    No, I never thought that'd be necessary as I've never needed to do that before and I would have thought the negative is in such close contact with the paper that it wouldn't matter that greatly (or as greatly as I'm seeing). Maybe I'll try a very long exposure with the facial tanner to see if that's the problem.
     
  25. Neil Miller

    Neil Miller Member

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    Hi Akki,

    Peter Frederick, who invented the temperaprint process, has used peeled RC negs to good effect. I read the method he used quite some time ago, so I might be forgiven for some errors! The method was something along the following lines:

    1. "Bruise" an unimportant corner of the negative - eg, hit it with a blunt object! The object is to stress the corner, possibly partly delaminating it, but not breaking the surface.

    2. Put it in a tray of nearly boiling water. The bruised edge starts to get water-logged first.

    3. begin peeling at the bruised edge. If you feel resistance, let it soak a bit longer. You can top-up with hot water as you go to maintain the temperature.

    4. When the plastic layer has been peeled from the paper backing, it usually still has bits of paper stuck to it. Let it soak until paper is easily rubbed off.

    5. Rinse and dry.

    I haven't used the method, so can't vouch for it being simple or quick. I have read elsewhere of people rolling the plastic layer around a pencil or rod to make the peeling easier.

    I recall that unpeeled RC paper was used too, but because it is not a simple sandwich (it has - maybe - 4 layers, one of which is a baryta layer for whiteness and opacity) it is very slow, as you found out. I don't think waxing or oiling helped much because of the baryta layer (could be wrong) and sometimes it had side results like making the paper structure/grain more visible, depending on the medium used.

    Good luck,
    Neil.
     
  26. Neil Miller

    Neil Miller Member

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    Just a quick thought about the blurring - maybe during the 3 hour exposure the paper expanded due to heat? I expect the contact frame would have to be super-tight to prevent such thermal expansion over such a long time.

    Regards,
    Neil.