Just thought I'd jump in here and add what I've been dealing with. Last year I bought a 100-pack of 13x19 film and it was the non-waterproof, clear variety. I bought it from an ebay seller, I think it's made by these people: http://www.superjetusa.com
Anyway, they worked great. The only drawback was that the slightest drop of water on the film would dissolve the image instantly. I tile my transparencies together for most of my prints since they are bigger than 13x19, I had no issues doing that, everything lined up pixel-perfect.
When I ran out of those I bought a different package from fixxons.com, which were advertised as waterproof. Sure enough, these are cloudy and blueish. They print really well, and the ink looks a little denser and sharper than with the other type. Problem is, the images do not line up accurately when I tile them together. I've wasted a ton of ink and film trying to get around this but no matter what, the left side of the image prints out a good millimeter or two wider than the right (in portrait format). It's a little better when I flip one of the images 180 degrees, but they are still a little off. The only thing I can think of is that the "waterproof" material is causing some kind of distortion, and it's very frustrating. Obviously, if you're not tiling images it doesn't matter. Has anyone else dealt with this?
I've visited commercial shops that use milky or almost opaque film for their positives, with no problems even on extremely fine halftones. The ones I'm using right now are some cheap, letter-sized crap from Office Depot and have some rough coating on the printing side that make them slightly opaque, but they work just fine.
As long as they print well and aren't meant for blocking UV light, you are probably in the clear (haha).
Hello, The pearlish coating is for dye based ink adhesion. It has little to no affect on burning with a strong or even not so strong light sources. It is said that is water proof but in my experience that is debatable. If you dont like it look for "non-water proof transparencie film". Silk screen supply is a good source. Over all and Im a professional screen tech ( La-di-da ) that the water proof film comes out much more opaque than non water proof. Just for refernce sake Im running Epson, 2400, 4800 and a 7600 with dye based inks