Then wait a minute or so, giving it bursts of "rain head" water soakings with mains pressure. Underexposure is really easy to check - rinse both sides of the screen with water on washout (start with gentle rinsing on the ink/squeegee side, since this is on the far side from your light source), then spin the screen and start to wash the shirt / substrate side until the design turns a lighter shade (even lighter than when it was exposed and you removed the positive). The scum in the stencil is very light green, almost clear.our emulsion is bright green before exposure and green/grey after.Īs a heads up - it is UV light you are trying to block, so a positive that is not completely dark may still have amazing UV blocking properties. We always block the screen inside the frame with a piece of black foam board. I did an exposure step test and found our exposure time to be 6 minutes, so it will probably work out when we get our glass back. We had it cut so that the edges land mid-frame all the way around a 20"x24" frame, so never had to weight it down. We called the people at the old place and they found our glass and are holding it for us, we'll probably go get it tomorrow. I suppose that could be part of the problem, it's just not going to work without the glass. Since then, I have been taping down the vellum really good and not using any glass. The other day I tried to burn a screen with a small circular piece of glass from a nightstand.I think it had UV filtering in it because about a 5" circle in the center of the screen would not wash out. Am I under exposing a clogged screen ?Īny ideas ? I have a 180 shirt order pending, have to figure this out soon and quit reclaiming bad screens.Īfter we recently moved, we discovered that we had left our glass for screen burning at the old location. So I have symptoms of both over and under exposure.hard to wash out/over exposed, stencil blow out/under exposed. If you expose correctly, you can't "blow out" your stencil (ruin it) with water regardless, right ? I just moved into an apartment and have no means of hooking up my pressure washer, so I'm using a shower wand on the "jet" setting.should still be able to wash out a stencil, correct ? Stains might be from sensitizer in the emulsion. I'm kinda thinking that whatever that stain is on my screens, it won't let go of the emulsion. Then I'm working on it so long that everything that initially washed out starts blowing out bigger. The big areas of the stencil wash out pretty good, but everything else is a bear.and when it does start washing out there is an emulsion haze in it like the last of it just doesn't quite wash out. Here's my exposure procedure: 500w work light w/ lens removed at 17" above screen, exposing for 6 minutes w/ clear film and 8 minutes with vellum, emulsion is Speedball Photo Emulsion green in color. I am using a new batch of diazo type photo emulsion.Ĭould all of my problems be coming from a bad batch of emulsion ? I've tried screen opener and two different degreasers and they are still stained. ![]() Also, my screens are stained a light brown after I wash them out and degrease them. ![]() Same thing, really tough to get the stencil to wash out and an emulsion haze in parts of it that won't wash out. I added a couple more minutes to the exposure time. So I next tried vellum and it seemed to be solid black. I had light emulsion that wouldn't wash out of the stencil, so I figured that light was getting through my black ink on the film. I exposed a screen using clear film and the stencil was really tough to wash out.
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