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Akki14
08-10-2007, 03:54 PM
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?

Ria
08-10-2007, 04:14 PM
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

Akki14
08-10-2007, 04:21 PM
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.

keithwms
08-10-2007, 04:57 PM
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!

Akki14
08-10-2007, 05:55 PM
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.

Dave Miller
08-11-2007, 01:18 AM
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.

Akki14
08-11-2007, 03:45 AM
The only benefit of pealing a paper would be to reduce the exposure time slightly, and I question if it would be worthwhile.

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.

Dave Miller
08-11-2007, 03:51 AM
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.

I'm beginning to see your problem, with the English sun.:) 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.

Schlapp
08-11-2007, 03:52 AM
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.

Dave Miller
08-11-2007, 03:58 AM
That's a thought Schlapp, I had assumed that Akki14 was trying to print one of the alternative processes that demands UV rich light.

Akki14
08-11-2007, 04:49 AM
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)

keithwms
08-11-2007, 09:45 AM
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)

Akki14
08-11-2007, 10:33 AM
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.

Schlapp
08-11-2007, 02:06 PM
It works printing onto POP.

keithwms
08-11-2007, 03:53 PM
ah okay.

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

Photo Engineer
08-11-2007, 04:09 PM
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

Akki14
08-11-2007, 05:07 PM
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

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.

Photo Engineer
08-11-2007, 06:16 PM
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.

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

Ray Heath
08-11-2007, 07:33 PM
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

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

Photo Engineer
08-11-2007, 08:03 PM
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