> Good idea. How about going one step further - print an annulus >centered on each hole, do a TT to the board, remove the paper and >drill through the centers of the annuli?This is getting off topic of solder mask:
After posting and thinking on it some I had come up with the same idea - do a light TT then drill thru that, clean board good, then a standard TT with traces for etching.
I'm not as sure now - the TT paper I use is totally opaque preventing the holes from showing thru to line up with. I think my past method of drilling just a couple of guide holes is plenty. One change for double sided boards I wish to try is place top paper on board, make one pass thru laminator to stick paper to copper. Then drill a couple of guide holes, put bottom paper to board using the guide holes, then pass thru laminator for solid TT. After etching, then drill holes.
I've got a board to make this week - we'll see how it goes.
Ken H>