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screen printing => Screen Making => Topic started by: mhprinting on May 13, 2015, 09:29:55 PM
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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!
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First off, with films as cheap as they are to re-make, losing a film to this problem isn't the end of the world. There's more than one member here who doesn't re-use them.
Otherwise, if really dry screens and a dehumidifier and baby powder don't help, maybe nothing will.
The halogen light you are using probably does produce a lot of heat, so that is not helping. You exposing for four or five minutes? Does that unit have a cooling fan?
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I too have this problem, and have yet to find a solution. Living in Georgia during this time of year just sucks when it comes to humidity.
Best thing to do if you need to reuse the film is to just print off another. I'd rather spend the extra $1 than fool with the rest of that crap to save it.
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1) Make sure your water proof film is good quality. I can not stress this enough.
2) Make sure you are putting down as little ink on your film as you can get away with. My droplet weight is currently set at 5.
3) Double check that you are not "over coating" your screens. If your eom is really high then you are retaining a lot of moisture in that thick layer of emulsion.
4) Heat from your exposure unit is NOT your friend. It will cause the remaining moisture in your emulsion to "leach out" (I need a better term for this). This is what grabs your film and ruins your film/image area (sometimes).
I have noticed that not all emulsions are created equal when it comes to retaining moisture. I am currently using Saati Textile PHU and I almost never have a problem with my film sticking to my screens. Even when my exposure unit gets up to 90-95 degrees plus when exposing 10 screens + (nuarc 3140).
I am currently trying out Murakami's SP-1400W and I am seeing films sticking some as the exposure unit heats up/as my emulsion coats are a little thicker (gotta test everything right?)/as the humidity climbs a bit. My exposure times on the 1400W are almost double what the PHU's are (180 mesh PHU = 80 LTU - 1400W = 150 LTU). So my exposure unit gets hot faster, thus exacerbating the issue.
I have used other brands of emulsions with similar sticking results. The Saati PHU has worked best for me. Humidity in the drying cabinet is between 30%-40% and stays in the 80's temp wise.
Hope this info is of help!
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How long do you let the film sit after printing? I only have this problem with large thick areas on screens that go straight to the exposure unit.
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we have this issue all year long with water proof film. When it sticks you would think the ink was made from super glue
The only real fix we have is like Frog said use a coating of powder.
We simply dump a shot of powder on the film side of the screen, spread it by hand to dust up the necessary area and expose as usual.
the other fix is not to use WP films. It is the coating that makes the film waterproof that also makes the film stick to the moisture in the emulsion.......you can't dry it enough.......go for the powder.
mooseman
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We only really had this issue when either we didn't allow screens to dry completely or film was right off the printer right to burning the screen (ink still wet/tacky). Rare when it happened.
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honestly, I had this problem with waterproof film only.,and it was still rare.
Non-waterproof film was never an issue. I got better films and screens with that stuff.
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It happens here all year. Pure Photopolymer emulsions and waterproof film used here and it's always there, unless it's a 305. I can undercoat our screens and have less issues, but with normal EOM and PP emulsion it doesn't go away, even with film that's years old. We go through a container of baby powder every 3-4 months. It's a bandaid, but I don't want to use dual cure emulsion so we live with it and sprinkle our screens with baby powder prior to placing film. Takes about 5 seconds and it doesn't affect the exposure or detail to any great degree.
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like Alan said, happens here any time of year with the pure photopolymers. Yet another reason I love the SP1400: no sticking.
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You also get no sticking with CTS. 8)
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Thanks for the input guys! Seems like it's happening/happened to all of us. I print all the films all at once, line them up on the light table, and then burn them. Usually about 30 mins after printing from the printer. I tried putting a lot of baby powder on the film and it still sticks. I'm usually burning screens at 2-5mins. Looks like it's a problem that doesn't have a solution. And like Frog said, it's not the end of the world to reprint films. It just less convenient having to reprint them. Thanks again guys!
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Also, I've had some success using udc-2, but I don't want a diazo since it's takes a lot longer to burn on my 1000w halogen exposure unit (8-12mins) compared to 2-5 mins with photopolymer. I was recommended by my supplier that Ulano orange is a "tack free" photopolymer, but I have no problems with pv. What do you guys think?
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And like Frog said, it's not the end of the world to reprint films. It just less convenient having to reprint them. Thanks again guys!
Actually, those who don't re-use also don't need to figure out and use a storage system for these rather fragile gems (that accumulate really quickly!)
When we used cameras, and it was a bit more of a hassle to re-do, it was a necessity. Nowadays, it's a toss-up
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I've rarely had this problem with my OLD coating technique. But wowsers, I am NOW, BIG time.
I used to use only the sharp edge, 2 over 2, CCI WR25. I went to Greg Kitson's for the Greaves on Garments workshop, and decided I could learn to use the round edge, 1 over 1 or 1 over 2.
I just destroyed a stencil (using 1 over 2) trying to peel a 2 month old Fixxon's Waterproof film. It's what I normally use. This was THE superlative sticky film scenario in my 7 years of using Waterproof Films.
My screen storage runs in the low 20º Relative Humidity range. It's been HORRIBLE for 3 or 4 days peeling films, and I even used talcum powder. I pulled the screen out of storage and shot it with no delay on an underpowered NuArc 2125 metal halide.
This one was the worst, ever for sticking...on a 20-Newtons EZ Frame with 150-48 dyed S Mesh. It actually "split" the emulsion matrix away from the mesh in 2 spots (peeling off the shirt side of the stencil). I've personally never seen that before. Destroyed the film too.
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For the first time ever, we are dealing with this now. It's actually ripping emulsion off outside the image area so wrecking the screen and the film...ugh.
It's too dry here for it to be environmental, screen cab is easily 14% humid most of the time and overnight drying the films has not improved it. I think it happens when we're 10 screens in on burning. It's the LED unit ironically. I temped it today at 104˚ on the outside of the rubber blanket. Having our screen tech watch temp tomorrow and find the point where it's tipping over from "a little warm" to screen/film bummer.
So my guess is look at the heat first but absolutely +1 to everything else mentioned.
This is dual cure or, diazo added PP by the way. Our current PP emulsions are actually a little more 'matte' in finish.
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For us the only time we have the sticking issue is the humid summer on days it's almost humid enough to rain but doesn't or if I forget to empty the dehumidifier and only on screens we are using PHU or Kiwo Discharge. We use WP film from Spot Color or Nazdar and Cobra ink, films are usually at least an hour old drying in the office. That being said our screen closet is kept at 90-100 degrees and 30% humidity year round.
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brian...why are you emptying a dehumidifier? I would figure somebody as carfty as you would figure a way to fix that. Ours drains into an HVAC condensate pump, which in turn pumps it up to an overhead condensate line that was running from a different suite to the back of the building.
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Figured someone would call me out on that, I'm too cheap to buy a condensate pump plus it's about a 100' run around the shop for the hose to reach the slop sink.
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i figure it's easier than depending on somebody to remember...or a spilled bucket of water...either way, it's a pain.
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I've done 7 years coating 2 over 2 with the SHARP edge and I had almost no problems with sticking.
I also had ZERO EOM...or none to speak of!
Now that I have an auto I'm trying for the elusive One Hit White because otherwise I'm stuck in revolver mode on some jobs. I have one flash and only 8 heads, so I REALLY need to get my EOM up. But this sticking thing is new, and it's driving me nuts.
Before I had a dehumidifier in my screen closet, I used to spray the Fixxons films with Krylon Matt Clear during rainy weather. I may have to go back to that, but I'm not even sure that will work, its been so bad lately!
And it's raining AGAIN this morning in Wichita. !@#$%^&*!!
I've got to try either that whole cumbersome Matt Clear thang again, or new emulsion or give up on EOM. Or get my NuArc 2125 cooler somehow.
Or drive to Arizona to expose my screens.
I'm not big enough for a CTS or DTS or whatever the name is this week.
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Anyone here have their exposure unit housed in a climate controlled screen room? Ours is. Back when we used films we did not have the "sticking" problem.
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I've done 7 years coating 2 over 2 with the SHARP edge and I had almost no problems with sticking.
I also had ZERO EOM...or none to speak of!
Now that I have an auto I'm trying for the elusive One Hit White because otherwise I'm stuck in revolver mode on some jobs. I have one flash and only 8 heads, so I REALLY need to get my EOM up. But this sticking thing is new, and it's driving me nuts.
Before I had a dehumidifier in my screen closet, I used to spray the Fixxons films with Krylon Matt Clear during rainy weather. I may have to go back to that, but I'm not even sure that will work, its been so bad lately!
And it's raining AGAIN this morning in Wichita. !@#$%^&*!!
I've got to try either that whole cumbersome Matt Clear thang again, or new emulsion or give up on EOM. Or get my NuArc 2125 cooler somehow.
Or drive to Arizona to expose my screens.
I'm not big enough for a CTS or DTS or whatever the name is this week.
I'm in the same situation you're in. Ever since with the auto, my films have been sticking. Would a drying cabinet help?
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All our screen making is out on the production floor, screens are kept in a light safe environment
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I'm in the same situation you're in. Ever since with the auto, my films have been sticking. Would a drying cabinet help?
Nope.
I already use a drying "closet" for storage. They dry in there and just stay in racks until I need them. I can push it down into the low 20% RH range or even mid teens if I want (although the temp approaches 100º if I'm not careful) It makes no difference.
This is just a last few days phenomenon for me, just since I'm trying to get some EOM. If I went back to sharp edge coating 2 over 2, I'm golden...with my current setup. After seeing Kitson's setup, my whole gig is decidedly "ghetto" and I'm not going to keep making the same mistakes over and over and over. I'm inspired to streamline and improve. Determined, really.
I told Greaves I DON'T have 7 years of experience. I've had 1 year of experience, 7 times.
Them's the facts.
All our screen making is out on the production floor, screens are kept in a light safe environment
Yeah Brian, me too. I'm cramped for space. I had to snicker when I read Brad's "different suite" comment above. I call my print floor a dungeon. I wish I EVEN HAD a suite! All in jest, Brad! :) If I had room, I'd copy Kitson's screen loop, except I am pretty much stuck with films.
Until the emulsion is dry, there is zero problems with exposing them with all the UV energy you care to muster. I think you can probably spoil diazo powder with UV energy, but that's a different topic.
Stan
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Hey Stan, what emulsion are you using?
We saw sticking with Chromaline Chromablue... less so with Kiwo Onecoat... though I noticed more sticking when we started playing with longer exposures and my bulb is getting old... so I think heat is starting to create part of the issue for us as well.
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Kevin, I'm using WR 25 (CCI) and my blub is getting old too. I've got a new one in stock, so what is my excuse?? Dunno.... Busy texting to convince a self-diagnosed Arrhythmic Musician not to give up maybe? Ahem.
But I digress.....
I think heat is definitely part of my predicament. That and I'm basically starting over dialing in exposures. And trying to hold low percentage dots.
I wish I could see a video of someone using a Stouffer 21 Step Exposure Guage who knows how the heck to use it properly! Cause I can't figure it out. I wash out WR-25 from both sides and it utterly destroys any information the Stouffer might lend.
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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.
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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.
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Kevin, I'm using WR 25 (CCI) and my blub is getting old too. I've got a new one in stock, so what is my excuse?? Dunno.... Busy texting to convince a self-diagnosed Arrhythmic Musician not to give up maybe? Ahem.
But I digress.....
I think heat is definitely part of my predicament. That and I'm basically starting over dialing in exposures. And trying to hold low percentage dots.
I wish I could see a video of someone using a Stouffer 21 Step Exposure Guage who knows how the heck to use it properly! Cause I can't figure it out. I wash out WR-25 from both sides and it utterly destroys any information the Stouffer might lend.
I'm gonna forward you an email I had about that stouffer strip the other day... Still no real answers that we have acted on, but some more insight.
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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.
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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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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
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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.
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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
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No if spread thin w/ cloth or fingers.
You don't need much. Makes all the difference in the world sometimes.
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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.
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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.
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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
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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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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.
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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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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.
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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 (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 (http://www.rivercitygraphicsupply.com/products/details/chromaline-prototype-non-film-sticking-emulsion-plastisol-inks)