Renegade Publishing

Duo is a special cloth made by a supplier in Germany that has since gone out of business! It's an open-weave cloth of one color, backed onto paper of another color to create a color shift effect. You can see a listing here, it's easiest to photograph on the Grape color; much more dramatic in person. Unfortunately, all the duo that exists at these retailers is all there will ever be, since the company went down.