Once upon a time, I sent out PCs to a long list of mail-art afficionados but then almost everyone (it seemed) found other artistic venues. I continue to make 6x4s at the risk of being labeled a miniaturist, which it seems I may be anyway. Most of my PCs are made on recycled cardboard which means someday they will waste away but so does everything and not working with archival papers keeps that right up front. Plus I'm using some of the massive amounts of paper that comes my way unbidden. Perhaps these are pallages, they aren't purely collage or painting. I've found that the combination of the two disturbs some collage artists who prefer their collage straight.
I've posterized these on Elements. It flattens the variety of colors I used in the originals in unexpected ways that bring more attention to the colors.