Jennifer McGuire used an interesting technique in today's Online Card Class - stamping with Versamark over the top of Hero Arts shadow inks to give a kind of watermark effect. (it works with some other inks, too, but I have the Hero Arts ones). Jennifer used it to cover a whole card, but I cut down a piece to create a patterned panel.
CASology Week 131: Birthday
Simon Says Stamp's Wednesday Challenge - Anything Goes.