# Keeping film positives from sticking to the emulsion



## SNR (Jan 29, 2008)

So i've been having an exposure problem that i think i've fixed. I was printing my film positives so that the non-porous side was coming in contact with the emulsion and then exposing. If I didn't do that, the ink from the film positive loved to stick to the emulsion and the positive was pretty much ruined after that. The film i was just using had really fine detail that wasn't washing out. I think that when i printed the film so the non-porous side was in contact with the emulsion, it was undercutting the image and all that nice, fine detail was getting locked in the screen.

So my question is: how do i reuse my film positives if the best way to use them is to have the porous side in contact with the emulsion? Is there a way to seal that side and not affect the exposure AND keep the ink on the film from coming off?


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## VinylHanger (Jul 16, 2010)

It sounds like your emulsion isn't totally dry from the washing out. It will cause steam to rise between the film and the emulsion. You just need to make sure the emulsion and the ink are totally dry. Being a small time operation, I can usually wait a day or so, or hit it with a hair dryer.


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## words on a shirt (Dec 23, 2010)

Not 100% dry can cause this for sure. But I also had one stuck once that I left on exposure unit about a hour after exposure. I shut unit down and left for lunch with client, left weight and dark cloth on unit. Got back and it was stuck. Blamed it on heat. Could have been since our screens are dried at 45% humidity for no less than 24 hours before use. Just a thought to nibble on.


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## Pvasquez (Feb 19, 2011)

Just so you understand about the hair dryer (not a heat gun) you want to use it on the emulsion not the film. When ready to expose take your screen blow dry the side that will make contact with the film so you get any moisture off that top layer of emulsion for about 10 seconds and then put your film on correctly (ink making contact with emulsion) and this should take care of the problem adjust as needed.


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## TYGERON (Apr 26, 2009)

I would venture to guess you _aren't_ using "waterproof" film. 

You are correct about the undercutting also.

Waterproof is generally more expensive but you can find great prices from some sources and it good if you stack them to keep.


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## VinylHanger (Jul 16, 2010)

I get this with waterproof film if I don't get it dry.


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## SNR (Jan 29, 2008)

Looks like I'll need to invest in some new film positives, the waterproof kind. Thanks everybody, you guys rock.


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## bleeder (Jan 8, 2010)

Just be sure to have a dry glass when exposing a water proof film. My exposure unit is in my garage, and it rains a lot here. If I don't heat the glass top and remove the moisture, the whole textured side will fuse to my screen.


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## leunam12 (Feb 23, 2008)

the problem is the film, I used to have the same problem until I switched to a different brand


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## alan802 (Mar 24, 2008)

We've had this issue for years. We've changed emulsions, changed film, all waterproof, dehumidifier, nothing really works when it's humid. Not even letting the screens dry for weeks, nothing. Except baby powder. Dab a little on the screen and spread it around, that's the only fix we have found. Most dual cure emulsions don't stick, and some photopolymers that are coated very thinly don't do it, but any screen that is significantly coated for a thicker stencil will do this, baby powder is our only answer. I won't use dual cure emulsion and adding the baby powder adds only a few seconds to the process, so that's what we do on screens with thicker stencils.


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## latitude42 (Sep 26, 2007)

I had same thing happen...I just print the image in reverse so the ink does not come in contact with the emulsion...
Latitude42


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## cornpopps (Jan 8, 2010)

I seem to have this issue on colder weather damp days. I use WP film but when the moisture in the air is higher it seems to stick to my emulsion. During summer when its dry air outside that issue seems to be eliminated.


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## sassygirlztees (Apr 5, 2011)

latitude42 said:


> I had same thing happen...I just print the image in reverse so the ink does not come in contact with the emulsion...
> Latitude42


Wow! Learned something already! Simple yet a great idea that I hadn't thought of when i run across this from time to time.

Thanks!

Angela


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## alan802 (Mar 24, 2008)

latitude42 said:


> I had same thing happen...I just print the image in reverse so the ink does not come in contact with the emulsion...
> Latitude42


You can get away with that for almost all the designs you'll likely print. But if your doing high detailed halftones or really high end prints, you'll not produce the highest quality stencil that you could. We used that technique for several months but occasionally had on-press issues due to the additional light scatter you'll encounter when exposing your screens with the film backwards. What I'm getting at is your stencil will not be as an exact replica of your film as it would be if it were exposed with the film placed on the stencil the correct way. It's up to you to determine if your results are acceptable for whatever it is you're printing, most occasions you'll be fine, but keep your eye on it.


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## latitude42 (Sep 26, 2007)

Works great for spot colors...
Latitude42


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## foot print (Jun 2, 2010)

sounds like your emulsion may not be completely dry and or your films not all the way dry either. I use water proof film from Fixxons love the stuff. I print my films and let them sit for about 5 minutes and no issues. My screens are dried in a DIY drying cabinet heated with a small space heater. here is how i know if my ink is dry yet, After i print my film I flip it over and i can see that the film has a milky look once the ink is dry my film looks black.


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## edward1210 (Nov 7, 2009)

But the image than will transfer to te exposure unit glass


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## missswissinc (Feb 21, 2012)

thanks I just started to go over to ink jet film and believe me I'm staying that way. good to know that once the ink doesn't look milkey on the back side the pos is dry.


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