Katy jo,I don't know if you saw but I had that problem and I figured out that my transparency wasn't opaque enough. Therefore some light was getting through the image on the transparency while I was exposing the screen to light, slightly hardening the emulsion.If the image on your transparency isn't solid black this will happen. At first, I had set my printer to 'normal' on regular paper. I then set it to 'transparency' which was EVEN WORSE. Finally, I set it to fine, regular paper, vivid colors and I got a very black solid result. However, I could see that some light was still going to make it through the image so I ALSO only exposed my screen for 5 minutes and 20 seconds rather than the 8 minutes that is recommended. After that the emulsion came out LIKE BUTTA. No scrubbing, no rubbing, just the hard spray hose in my sink.
This was my suspicions after reading a few more tutorials and blogs on the subject. Thank you so much for telling me and now I can quit banging my head against the wall about it all! So just so I'm understanding if it's not opaque enough it will wash off?! You are so smart!!! Thank you again, I appreciate this more than you'll ever know!