Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison
a) buy an exposure calculator film. Ulano and Chromaline make excellent ones. It will really help you narrow down your exposure times to be optimum.b) if your exposure unit does not have an integrator, then re-calibrate with the exposure calculator every couple months, and at every lamp changec) To build thick stencils, I always coat 1:1 starting at the print side, moving slowly with firm pressure. Dry, then add one or more coats to the print side.d) For each coating method and mesh combo, run the calculator. Yes this may mean dozens of exposures. Do it.
1100w metal halide and you still need over 400 seconds?That is a bit fishy. You sure your emulsion is OK?My Nuarc 40-1K which is Mercury (Slower) exposed ChromaBlue in less that 90 seconds.
Quote from: DKgrafix on August 15, 2013, 07:14:46 AM1100w metal halide and you still need over 400 seconds?That is a bit fishy. You sure your emulsion is OK?My Nuarc 40-1K which is Mercury (Slower) exposed ChromaBlue in less that 90 seconds.Agreed, when I had a home made MH I was running hmm... 3 minutes? I'd have to ask my guy if he remembers, I've never looked back after getting my 3140 (best purchase I ever made!!!).Also, we recently had some "under exposed" issues and it was due to the emulsion getting "rank". Smelt like doo doo in the bucket but my guy couldn't see throwing out 1/4 of a bucket of emulsion and was still getting "good" stencils out of it, but our exposure times were getting higher and higher and we were still technically "under" (we run an exposure calc strip on EVERY screen). I finally told him to stop using it and he cut back exposer, WAY back and we over exposed a couple of steps... so definitely our problem.If you have a super thin layer of emulsion then your times could be dramatically different. Also what is the distance from bulb to film? Inverse square law comes into play on your exposure time. It's possible that your time is "correct" for your distance.