Author Topic: Films sticking to screen after exposure  (Read 9360 times)

Offline dj

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Re: Films sticking to screen after exposure
« Reply #30 on: May 15, 2015, 05:33:33 PM »
Try this, first when you print your film print a mirror image. This allows you to put the slick (non printed) side of the film against the screen. Then lay a clear sheet of plastic film slick side up on your exposure glass, this allows the ink to be in contact with slick side of film facing light. This has worked for us for years.

Though not huge, this will cause a little choke on positive dots and spreads in the voids. No biggie once you figure it into your dot gain calculations.

We old timers have, more than once brought up these stoneage camera techniques for pre-computer era film output and screenmaking.

Old timer I am lol. I have never found an issue with the film thickness on a single light source and we ARE printing on fabric remember. I would never consider using powder and we never have to make films twice.


Offline Frog

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Re: Films sticking to screen after exposure
« Reply #31 on: May 15, 2015, 05:54:14 PM »
Try this, first when you print your film print a mirror image. This allows you to put the slick (non printed) side of the film against the screen. Then lay a clear sheet of plastic film slick side up on your exposure glass, this allows the ink to be in contact with slick side of film facing light. This has worked for us for years.

Though not huge, this will cause a little choke on positive dots and spreads in the voids. No biggie once you figure it into your dot gain calculations.

We old timers have, more than once brought up these stoneage camera techniques for pre-computer era film output and screenmaking.

Old timer I am lol. I have never found an issue with the film thickness on a single light source and we ARE printing on fabric remember. I would never consider using powder and we never have to make films twice.

Well, with a scope powerful enough, you should be able to see the difference in small dots shot emulsion to emulsion vs. through the film. As I said, though,  through only 4 mils or so, a very small difference, but when we contact printed film positives or negatives to do this on purpose, that was also a single point light in the contact frame.
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Offline Rockers

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Re: Films sticking to screen after exposure
« Reply #32 on: May 15, 2015, 06:31:06 PM »
Try this, first when you print your film print a mirror image. This allows you to put the slick (non printed) side of the film against the screen. Then lay a clear sheet of plastic film slick side up on your exposure glass, this allows the ink to be in contact with slick side of film facing light. This has worked for us for years.
Doing it this way for the last 10 years and never had any issues with it. No need to add another piece of film, at least not for us. Using AccuArt 3

Offline dj

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Re: Films sticking to screen after exposure
« Reply #33 on: May 16, 2015, 11:12:36 AM »
Try this, first when you print your film print a mirror image. This allows you to put the slick (non printed) side of the film against the screen. Then lay a clear sheet of plastic film slick side up on your exposure glass, this allows the ink to be in contact with slick side of film facing light. This has worked for us for years.
Doing it this way for the last 10 years and never had any issues with it. No need to add another piece of film, at least not for us. Using AccuArt 3

Agree, at times we had used some cheap films and ink, so just as a precaution, and not knowing what others are using out there it doesn't hurt. The extra film (or clear pastic sheet) is between the image and glass and keeps your glass clear of ink.

Offline John-ibeinky

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Re: Films sticking to screen after exposure
« Reply #34 on: August 30, 2015, 10:17:35 PM »
This is not a problem we have to any great extent, but I do have a question. Does not the baby (talcum) powder cause pinholes? There must be something I do not understand. Thanks, John

Offline GaryG

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Re: Films sticking to screen after exposure
« Reply #35 on: August 30, 2015, 10:53:08 PM »
No if spread thin w/ cloth or fingers.
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Offline Itsa Little CrOoked

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Re: Films sticking to screen after exposure
« Reply #36 on: August 31, 2015, 06:54:45 AM »
When the humidity is high or I have a coarse mesh with a lot of emulsion to expose or I am running enough screens back to back to get my glass really hot, I still have problems with my sloooow emulsion. Powder helps.

I make a "pounce" bag with the powder inside. That is a old signpainter's trick, and yes...I am an old signmaker with a certain emphasis on OLD. A sock works, or a square rag. It's just a bean bag type of affair with a little cotton or even a paper towel to add bulk. I makes about a 2-3" ball. I just tap it a time or two on the films and smear it around. If it is REALLY humid like it is today, I might even smear some onto the dried emulsion, although it makes tape stick poorly.

But yeah, if you had big lumps of white powder it would about have to cause exposure problems.

I use genuine, bonafide white pounce powder, because it isn't scented. I dislike the perfume. But when my bottle is gone, I don't know if I can source white pounce powder easily. I've had it for several decades.

This one's black powder, but it is easy to see. Sign painting isn't quite a lost art, but wow... The comparison to "buggy whips" is an easy one.


Offline whitewater

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Re: Films sticking to screen after exposure
« Reply #37 on: August 31, 2015, 08:01:32 AM »
we us the same emulsion. It happens to us when its really really humid up here in ny. Which is probably like that for most of the year where you are.


in addition to the dehumidifier, i put a fan on them. The times i dont put a fan it seems to happen more. For us it helps.


Offline ABuffington

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Re: Films sticking to screen after exposure
« Reply #38 on: August 31, 2015, 12:40:38 PM »
Talc or baby powder.  You haven't seen sticking until you go to Honduras where it is 90 degrees, 95% humidity, and raining outside, the film will tear before it comes off!  Talc or baby powder lightly sprinkled onto the screen and spread out by hand works wonders to save films.  Also the hotter the glass the more emulsion (any) wants to stick in these conditions.  Fine talc transmits the light, no pinhole issue here.

Al
Alan Buffington
Murakami Screen USA  - Technical Support and Sales
www.murakamiscreen.com

Offline Frog

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Re: Films sticking to screen after exposure
« Reply #39 on: August 31, 2015, 01:04:20 PM »
I guess the positive side to that kind of humidity and film sticking that aggressively would be good undercut reducing emulsion-to-emulsion contact even with merely a compression lid. LOL! I don't need no steenkin' vacuum!

I remember a time that our seat-of-the-pants type guys down under used "terps" to adhere film with no frame.
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Offline ZooCity

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Re: Films sticking to screen after exposure
« Reply #40 on: August 31, 2015, 02:17:11 PM »
When the humidity is high or I have a coarse mesh with a lot of emulsion to expose or I am running enough screens back to back to get my glass really hot, I still have problems with my sloooow emulsion. Powder helps.

I make a "pounce" bag with the powder inside. That is a old signpainter's trick, and yes...I am an old signmaker with a certain emphasis on OLD. A sock works, or a square rag. It's just a bean bag type of affair with a little cotton or even a paper towel to add bulk. I makes about a 2-3" ball. I just tap it a time or two on the films and smear it around. If it is REALLY humid like it is today, I might even smear some onto the dried emulsion, although it makes tape stick poorly.

But yeah, if you had big lumps of white powder it would about have to cause exposure problems.

I use genuine, bonafide white pounce powder, because it isn't scented. I dislike the perfume. But when my bottle is gone, I don't know if I can source white pounce powder easily. I've had it for several decades.

This one's black powder, but it is easy to see. Sign painting isn't quite a lost art, but wow... The comparison to "buggy whips" is an easy one.

That is perfect, doing this today, thanks.  Everyone's tired of the powder getting everywhere in the screen room.  8 years of printing without this issue and now having to add this step is annoying. 

Oh and you can find unscented talc for billiards players.

We are still dealing with this.  It's clearly the 100˚+ heat that happens on exposure.  Will solve in the long haul by lowering screen room ambient temp and correcting the, imho, inadequate air flow/intake on the expo so that it is both filtered and better matched for the heat output of the unit. 

Offline BKerfes

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Re: Films sticking to screen after exposure
« Reply #41 on: August 31, 2015, 05:30:32 PM »
Kiwo MultiTex has a slip agent added to it to help lower the risk of sticking while exposing.
As everyone else has said, Humidity plays a key factor!
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Offline ZooCity

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Re: Films sticking to screen after exposure
« Reply #42 on: August 31, 2015, 05:41:02 PM »
Kiwo MultiTex has a slip agent added to it to help lower the risk of sticking while exposing.
As everyone else has said, Humidity plays a key factor!

Waaaaay back we went through a couple gallons of a Kiwo dual cure that was engineered to have a crazy good RZ.  It was great to print with (on the manual at that time), almost slippery feeling.  I know emulsions are a balancing act where adding one positive attribute often introduces a negative but I wish they all felt like that dual cure did. 

Offline Rockers

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Re: Films sticking to screen after exposure
« Reply #43 on: September 04, 2015, 05:52:54 AM »
Hey guys,

Can't really seem to fix the problem of my films sticking to the screen after exposure.  I tried a couple different ways to fix it, but no luck.  I'm currently using textil pv using the glisten method to coat screens.  My dark room is in the warehouse area of the shop.  My dehumidifier's reading of the room humidity is around 38-44%.  I can't get it any lower than that since I'm from the south.  I tried drying my screens in a room inside the office area since there was A/C and my dehumidifier.  My room humidity was reading 40-44%.  Didn't quite understand why it was the same as my dark room in the warehouse area.  I coated the screens in the morning and left them overnight to dry in the office area room.  Film was still sticking.  I tried using some baby powder and it would still stick a little bit, but not as much.  From time to time, the ink from the film would stick to the screen causing me not to be able to reuse the film.  I tried switching to kiwo tack free emulsion + baby powder and no luck.  I thought it could be from the glass from the exposure unit getting too hot, but I burned a screen first thing today at 2mins and it still got stuck on the screen.  Could it be the films that I'm using?  The ink from the printer?  Maybe the static?  It gets quite annoying having to peel the film off the screen every time.  I have an epson artisan 1430 using the stock ink w/ accurip droplet at 13.  Exposure unit is a workhorse point 1000 using a 1000w halogen bulb. 

Any ideas why my films keep sticking to the screen?

Thanks in advance!

You might be interested in this emulsion then
https://www.youtube.com/watch?v=RKADY7tASis

They stock it at RiverCityGraphicSupply. It`s aChromaline product, seems to be beyond top secret though, it`s not even on the Chromaline website.

http://www.rivercitygraphicsupply.com/products/details/chromaline-prototype-non-film-sticking-emulsion-plastisol-inks