Ink from Film Sticking to Emulsion

[ABuffington]

Most have hit upon the solution.  Talc or Baby Powder, it won't create pinholes.  In the tropics you have to use it to avoid the tack issue, w humidity in the 90% range.  Usually caused by heat from a Metal Halide lamp in combination with humidity.  A little talc preserves all films, especially in shops that expose a lot of screens in an enclosed 5k-6k MH unit.  LED's have no heat so less tack.  Tack can be useful.  We have an emulsion designed to promote tack and film adhesion to shoot better halftones.  Great for real film, tough on ink jet films.  So the talc does fix this.

Al

[willy35]

I output film in mirror, ink is not in contact with the emulsion.

I read this is not the best, but honestly I see no difference when exposing critical job like halftone job.

[Frog]

I output film in mirror, ink is not in contact with the emulsion.

I read this is not the best, but honestly I see no difference when exposing critical job like halftone job.

As has been pointed out, light will sneak through the thickness of the clear film and slightly undercut your open dots.
Perhaps, using this old traditional method of choking, you have also stumbled upon a way to compensate for dot gain. 

[willy35]

I apply a custom curved before sending to accurip.

I will expose the normal way on my next critical job and compare again.

Thank you

[mooseman]

The simple all around fix is to simply use some powder. Simply throw some on the screen and spread it around with your hand to spread and coat evenly the film side of the screen right before exposure.
Controlling the humidity takes more attention, time and energy and you are chasing a seasonal / weather influenced / geographic variable.

We have experimented with over drying screens in  a 95- 100 degree environment for 6 hours and the ink still stuck to the emulsion.
We have tried damprid http://www.damprid.com/ in a closed cabinet with coated screens and some ink still sticks.

Remember (at least in our situation) it is not the film that sticks to failure  but the ink coating on the film.
Yes our waterproof films did stick to the emulsion in the worst cases  but the true damage came when the ink pulled off the film creating a DTS the hard way!!!! 

Like everyone the issue here in the north east was way worse in the spring / summer than in winter.
the stop drop and roll fix, (in our multi hundred $ business) is simply to stop trying to fix the environment and throw some powder on the darn screen. .......................Just go print something and leave the environmental issues to Al Gore
mooseman