One for the road ....

VERY Cheap AND very good results.

When you printout your designed board twice on two transparent sheets, you can use both to get a very high contrast.

A handy tip : make your second sheet a little bit smaller than your first(cut the edge). And tape them together to have a good alignment. Extend your exposuretime and look at the results.

This works better cause your printer cannot print twice the same 'pinhole-faults'.

Remember to print-out both at the same time, and same orientation! Cause printers do have a high XY-instability.

Best Regards.