[Skidream37]

Has anyone had issues with transparency film sticking to the emulsion when exposing? I have tried extra dry times on the emulsion and films to eliminate moisture factors and even did reveres prints on the film to avoid the print side of the film. I use Black Max inks with Rip software and MH lamps.

 

[lbridenstine]

I just started printing and had this problem a couple times in a row with a different setup. I think my emulsion was too thick, because I was originally coating the screen with a squeegee and the film stuck during exposure and some of it peeled off, then I got a scoop coater and used the thin side of it and when I exposed screens after that, they haven't stuck. Hope this helps.

 

[vastex]

If there is any moisture left in the emulsion, your positives may stick, especially the coating on waterproof films. Even high humidity can cause a small amount of moisture to stay in the emulsion. I don't know if you are air drying or not but a drying cabinet or heated air should evaporate the remaining moisture.

 

[lbridenstine]

If there is any moisture left in the emulsion, your positives may stick, especially the coating on waterproof films. Even high humidity can cause a small amount of moisture to stay in the emulsion. I don't know if you are air drying or not but a drying cabinet or heated air should evaporate the remaining moisture.

Personally, I am air drying and using waterproof film, so maybe I did just let the more recent ones dry longer?

 

[vastex]

Even a fan or small space heater on low to move some air could help out quite a bit. Our dryers work by blowing filtered, heated air across the screens to dry them in about 20 minutes.

 

[lbridenstine]

Even a fan or small space heater on low to move some air could help out quite a bit. Our dryers work by blowing filtered, heated air across the screens to dry them in about 20 minutes.

That would be much better than waiting over night. I'll have to look around for a fan, I haven't been able to find any in my house for some reason, I don't know where they all went.

 

[vastex]

That would be much better than waiting over night. I'll have to look around for a fan, I haven't been able to find any in my house for some reason, I don't know where they all went.

The only thing you need to be careful with if you are using a fan is to not blow dust onto the screen. Any contaminants will stick to the wet emulsion and could cause pinholes.

 

[ScreenFoo]

+1 Vastex-- a hygrometer is a very inexpensive addition to any screen room--I've had this problem, but only when it rains. Luckily, it's usually not too much of a problem in the semi-arid region I'm in.

Once you get over 50% relative humidity, there could be a few problems in your pre-press that can carry over to press.

 

[Fenrir]

Target in my area (northern South FL) had some serious clearance (70% or higher) on space heaters, you may want to take a look if you have one near you.

 

[lbridenstine]

If I find one, I'll be sure to wipe it down before using it. I assume it shouldn't be close enough to actually blow directly on the screen while the emulsion is wet?

I might have a space heater... I thought heat can pre-expose the screen?

 

[Skidream37]

Thanks everyone. The problem was with humidity and heat. Turned up heat about 20 deg. and went to a fluorescent exposure box. The other factor was placing the print side of the film against the emulsion. I too had some thicker screens doing a 2/1 and 2/2 coverage for some reverse prints on heat transfers. I went back to basics with a 1/1 coat and the WBP Hybrid emulsion. The extra heat from the lamps pulled out the moisture and made the ink stick. The Dual Cure is much better than the Pre-Sensitized. I tried mirror printing the film to keep the ink off the emulsion and that seemed to help as well. I haven't tried any reverse printed halftones but I don’t think the thickness of the film will be much of a problem with non-contact exposure. Cross Link, I think they call it? We called it scatter.