Ok, something went wrong with the exposure...I think.
I have a big screen with a 210 mesh count. The mesh is yellow and it was coated with a blue emulsion.
I layed the image down on the glass, then the screen, then some black fabric then another piece of glass then some heavy books. I exposed the screen for 2 minutes. Was this where I made the error?
So, then I went and began to wash the screen. I did this in the dorm shower. (Probably not sufficient.) After a few minutes I could begin to see the image. The places where I wanted the ink to go through (the image) were a light yellowy green while the places I didn't want the ink to go through were a darker green.
So I clamped the screen down after it had finished drying and put some ink on. I pulled the ink went the squeegee and NOTHING went through. (groan.) So I was thinking, did I expose it too long? Does anyone have experience with the yellow mesh?
So I thought that maybe it needed to be pressure washed to clear the parts that needed to be cleared. So, I found a hose and sprayed it thoroughly. NOTHING. The water didn't want to go through anywhere.
Sensing that something went wrong, I tried to reclaim the screen with some emulsion remover. After spraying the emulsion remover on and waitning a little bit, I hosed it down and alot of the blue emulsion around the perimeterof the screen (the part that didn't get any light) came off, but alot remained around the image.
Now, the places where I wanted ink to go through are greenish, and the parts I didn't want ink to go through are yellow (the mesh color).
Does anyone know what happened? Did I expose it tooo long? Not enough water pressure during the first washing??
I don't know what kind of emulsion it was either (that's a pretty important detail). When I bought these big screens, they came precoated.
My light set up is a a piece of glass about 22 inches above 2 500 watt lights. I had done a screen for a 15 x 15 image and I used 1 light. That worked fine. But the design I did today was about twice that size so I used 2 lights.
I may have another problem now: I have tried to reclaim the screen and there's a greenish ghost. Is there a chance that the pores of the mesh could be clogged now with the over exposed part? Is the screen useless now, or is that just a ghost?
Sounds like you didn't wash it out enough the first time - the print areas should be yellow (mesh colour) but open - if the mesh still had blockages (and it doesn't take much, just a last little layer of emulsion) that would be why it looked like it exposed but then nothing printed.
By that point you were fucked. The rest (washout blues) comes from trying to print on a partially exposed/washed screen.
Get some more emulsion remover, scrub it in good, and then pressure wash with a pressure washer, not a garden hose with a nozzle.
then get some haze remover and give er hell.
that should clear the screen - you can see blockage if you hold it up to a light, use a magnifying glass if you are unsure. the people who coated the screen should be able to clean it if you can't.
If a screen was cleaned/degreased/coated properly, and the exposure was enough, and your posi good and black, you will not wreck a stencil by over washing out the image. Too much water is way better than not enough. and you need a sharp needle spray to wash it out. Hell, I'll give it a long distance blast with the pressure washer if it has really fine details (gentle and quick, and never in one place for very long)