When I order stamps from the post office, they package them with wonderful heavy cardstock. It is white. I use my cutting board that has a blade to cut it into 1 inch squares. But I also use cereal boxes, chipboard, and have been known to use a shoe box that had a map printed on the cover that was a perfect background. The 1 inch punch works on lighter stuff, but I always use at least two layers of anything a punch will punch. They really do need to be sturdy, and they really do need a good glue to hold the embellishments on. Those are the basic rules I go by.
Life is short.
Lick the bowl.