Screen filler works in the same way as Block Out, you put it on the areas of the screen you don't want ink to go through. If you're looking for a filler you can paint with, see Jacquards Block Out.

This screen filler is ideal for fixing pin holes, small spots, dust holes and generally patching up anywhere the screen may have broken down.

We always check our screens after exposing them, touch up with filler anywhere that's needed and you're good to go. If applying mid print run, ensure the area is dry before you put it on and allow the filler to dry fully before printing again. Always apply to the underside of the screen (not the side the ink sits in).