And I must confess that the photo above is fake. Sorry! It's like I've turned my blog into the National Enquirer. My auto-focusing camera refused to snap pictures at such low light, so I carefully Photoshopped a simulation. I considered adding an alien monkey boy to the image, but opted for realism. The glowing areas on the prints might look slightly more brush-strokey in real life, but this is pretty accurate.
I used the vampire bat and spider from Clip Art Etc., a great resource for vintage clipart.
You could also try a black Sharpie, or glue on black paper cutouts. Or brush a canvas with Mod Podge and then paint a black design on top.