Butterfly Mystery

I spent the day catching up on my volunteer duties at WeSnip in preparation for their next 3-day garage sale in a few weeks and came across this enchanting little piece of art which I just had to bring home (for the magnificent sum of $3).   I do love butterflies but I love paper art even more and especially the art of paper cuts.  

This, on closer inspection (see Extras) is very interesting.  As you can see the wings are cut from the paper and raised.  All good.  The question is how did the butterflies get "painted" without painting the background as well.  They were obviously "spatter" painted and then cut and raised, but if someone randomly threw paint at the paper, how come the butterfly wings are the only thing painted?  If you look closely the paint on a couple of the butterflies "continues" onto their neighbor.  The bodies and antenna are obviously painted directly on the background paper but not the wings.  I'll most likely lose a little sleep over this until I figure it out, or until somebody smarter than me comes up with an answer.