Films sticking to screen after exposure

[mhprinting]

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!

[Frog]

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?

[LoneWolf2]

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.

[Colin]

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!

[Screened Gear]

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.

[mooseman]

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

[GraphicDisorder]

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.

[mk162]

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.

[alan802]

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.

[mimosatexas]

like Alan said, happens here any time of year with the pure photopolymers.  Yet another reason I love the SP1400: no sticking.

[GraphicDisorder]

You also get no sticking with CTS.   

[mhprinting]

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!

[mhprinting]

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?

[Frog]

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

[Itsa Little CrOoked]

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.