Screen E-Book (.PDF) - MacDermid Autotype

OK. Use the smallest possible thread diameterto reduce the visibility of the moiré.Example: Going from a 34μm thread to a27μm thread can make a big difference.OK. If the MMC says you have strong moiréwith a set of film positives at 0°,15°,30°,60°,change them to 7.5°,22.5°,37.5°,67.5° - orvice versa. But beware of the simple moirébetween your 0° colour and the mesh.Problem solved/reduced.OK. If the mesh moiré is seen as lines ratherthan dots, make your printed dot-shaperounder. This will make the lines weakerand hopefully the dots won’t be so visible.OK. If the mesh moiré is seen as lines ratherthan dots the other possibility is that thesqueegee is amplifying the problem in thedirection of the squeegee stroke. Reducesqueegee pressure and/or stencil Rz.OK. If you really, really can’t change any ofthe above, and if you have an ugly wavymoiré, then get your screen stretchedproperly. You’ll have a moiré, but it won’tbe quite so ugly.MythsThere’s a myth that if only you had a ‘perfect’mesh then moiré would go away. Thisis false. Imperfections in the mesh maymake some moirés more visible by makingthem wavy, but if the mesh were perfect,the moiré would still be there. Don’t botherlooking for the perfect mesh to fix yourmoiré. Just use the MMC to find a meshthat doesn’t clash with your lpi/angle combination.Small imperfections in the meshwon’t alter the fact that it doesn’t clash, soyou’ll get no moiré.OK. Switch to MacDermid Autotype’s CapillexCP or CX, the ultra-low EOM, low, controlledRz. This reduces the intensity of themoiré. This is not just Marketing hype. It reallyhelps at the fundamental level.OK. If you have a low Rz stencil, use a thinnerink.OK. If you have a high Rz stencil, try to reducethe Rz without going too thick withthe stencil, then use a thinner ink.OK. Hope that the presence of the other 3colours will mask the moiré.99