sticky film problem

[Shanarchy]

Hey gang,

I know this has been discussed before, but I am having a major film problem. I use Fixxon's waterproof film. I know it is a humidity problem because I do not have this problem in the winter.

The problem: The coating on the print side of the film is extremely sticky. If you touch it with your finger, it will stick like it was glued to it. When you put it to the screen it will stick to the emulsion where you have to pry it off. Most of the times either pulling the emulsion (I use capillary film) to the point where you ruin the screen or the actually coating on the film will stick to the screen making washout impossible. I assume the humidity in the air is mixing with the film coating. Is this because these are low quality films? or do all films do this? I don't quite recall having this issue with other manufacturers film.

Question 1) What can I do to make these films useable. 

Question 2) If these are "waterproof" films, then why does a drop of water seem to mess with the coating?

Thanks in advance!

Shane

[Frog]

Wow, just the opposite of what I usually hear and have experienced: certain sticky emulsions taking the ink off the film!
Like you say. humidity sounds like the culprit, as I use Fixxons, and have no such issue in a generally dry environment.
Have you considered asking Fixxons?
Maybe they know of a bad batch, or could say outright, oh, our film has problems above 60% relative humidity, or what ever the amount is.

Then, have you considered a dehumidifier in the problem area?

[ebscreen]

I use Fixxons as well, and I have the issue of emulsion pulling
the ink off making most films one time only.

I put my films in the cabinet with my screens at %25 humidity for
a couple hours or days before exposing. They (should be) dry.

This and the d-max/min make me consider switching.

[Shanarchy]

Wow, just the opposite of what I usually hear and have experienced: certain sticky emulsions taking the ink off the film!
Like you say. humidity sounds like the culprit, as I use Fixxons, and have no such issue in a generally dry environment.
Have you considered asking Fixxons?
Maybe they know of a bad batch, or could say outright, oh, our film has problems above 60% relative humidity, or what ever the amount is.

Then, have you considered a dehumidifier in the problem area?

Frog,

I was just about to reply back that I was planning on calling Fixxon's in the morning. Then I realized they are located in California (I'm in MA) and are still open. They confirmed it is a humidity issue. Being located on the water in Massachusetts, our summers get extremely humid. I hate the winter so when summer comes I refuse to use AC. I love the heat. However, the film does not share my sentiments. They recommend keeping it stored in a cool dark area, preferably air conditioned. I am going to test a couple of options and will report back what I find works. Unless someone has done the testing for me already and would like to share what they do.

I tell you, the the more experienced I become, the more issues with the basics I get. I swear I'm moving backwards here.

[Shanarchy]

I use Fixxons as well, and I have the issue of emulsion pulling
the ink off making most films one time only.

I put my films in the cabinet with my screens at %25 humidity for
a couple hours or days before exposing. They (should be) dry.

This and the d-max/min make me consider switching.

More so than not I get the ink coming off the film onto the screen/emulsion in a couple of spots, too. Not a tone, but enough to make the film non-useable again. I don't mind that too much as I generally do not save the film. I know I am in the minority on that one, but I feel the film is less than $1 and for the lack of frequency of repeat orders of the same design it's not too big of a deal to me.

Now what is the d-min/d-max issue with the Fixxon's films?

[ebscreen]

I generally don't reuse film either, except for a few jobs that I store.

I do however put all film "currently in use" in a basket
that says "currently in use" in case a screen pops or was burned on the
wrong mesh or whatever the case may be. In an already rush situation,
it sucks to have to go back and print a film. (typically wasting more from
the roll/sheet)

Never had this problem before Fixxons.

D-Min/Max is the density minimum and maximum of a film. In a nutshell what's important to
us is that there is good contrast between the most dense (printed) and least dense (clear) area.

Fixxons has good D-Max but the D-Min ain't so hot. Makes for less contrast. The clear area
of a film should be crystal clear.

We're at %55 humidity average here, and my cabinet is half that. Just sayin....

[Frog]

I just picked up a dehumidifier on Saturday in SF, up in the foggy Twin Peaks area and the humidity was 70%!
Came home, plugged it in and it read 50%

[mooseman]

we have this very same problem, not using Fixxons film but we are using a waterproof brand.
We have pulled ink out of the film coating and emulsion off the screen. Times are when the film is so stuck to the screen even soaking it in water will not help.

Have no fear a fix is quick and simple. get some body powder the cheaper the better abscent perfume and oils I guess is best.

Rright before we expose we throw a couple shots of powder on the film side of he scren and kinda dust it around with a towel for a nice even coating.
We end up with a slightly powder caoted screen and the sticky problem is GONE!!!!
We don't see any down side to the quality of the stencil but have discovered the powder tends to retard the penetration of water to the stencil at washout. A little wipe down wth the flat of my hand in the washout booth solves this and everything is good again. Best of all your screens smell good too.

respectfully
mooseman
 

[Denis Kolar]

I use Fixxons and have the same issue. In Ohio it gets pretty humid too. I have dehumidifier and I keep it at the lowest setting. I think it is 35 or 40%. I have not noticed that it takes of that much ink so it would be an issue if exposing again. I think that my problem is that I expose as soon as I'm done printing. I think that the films should sit for a while to allow to completely dry.

[alan802]

We've dealt with this issue for years now and it's only on pure photopolymer emulsions, and only on those screens where the eom is fairly thick, 110's-156's predominantly.  I've done everything to our darkroom to insure the screens are drying properly, humidity levels are at 32% and the temp is from 80-85 degrees and regardless of how many days the screens are dried, it will still happen.  I'm all about trying to fix the issue instead of putting a bandaid on the problem, but I've spent many hours trying to get rid of the problem and it's just too quick and easy to put a light dusting of baby powder on the screen and wipe it around, 3 seconds and you're done. 

Maybe our screens aren't dry, but I can tell you that they can't get any "dryer" than they are, and we use waterproof film.  We used to flip our images and put the backside of the film into contact with the stencil, but you loose definition and burning halftones is a challenge so I don't recommend using that technique unless it's just big spot color jobs without tight registration.

[Denis Kolar]

Baby powder....... look at that

Thanks Alan

[Homer]

We get the same exact thing, we just went to a vacuum table about a week ago and this started to happen immediately.  Fixxons Film, SBQ emulsion too. . I may try the baby powder thing to see if it helps. . One thing we have done is kill the vacuum pump as soon as it draws tight, we don't let the pump go through the whole exposure time...seemed to help a bit. .humid as hell the past few weeks, we are a few hours from moosenuts so our air is about the same. . ahh the wonderful troubles of sh it you already had figured out and get to do it all over again. . .

[3Deep]

Homer you don't lose vac after you turn it off...ours stays on the whole time and shuts off when the exposure stops....I had a film stick the other day pulled all the ink off the film, but I,m thinking its due to how I coated the screen because, it only do that when I coat that way

 

[alan802]

Baby powder....... look at that

Thanks Alan

I just saw that Moose actually beat me to it.  He gets the credit.  I get some flack for using the baby powder technique but it seems that if I want to use SBQ and thicker stencils, it's what we've got to do.  I could move to a dual cure and 10% eom's on everything and not have this issue, but that would cause other issues.

[Frog]

I have more stick with some emulsions (Xenon Nova) than others (Chomatech PL), both, of course, pure photopolymer.

But Alan, I worry that thickness of EOM seems to matter so in this issue.

I would think that dry is dry, and perhaps your thicker stencils are not completely dry. Was it you or someone else who once talked about a moisture sensing device for this very thing? I know that you love gadgets.