I just opened up the box on my brand new (jewelry-size) rolling mill - I've never used one before. I read that cut-out paper makes a suitable pattern for imprinting and gave it a try on some copper sheet (approx 21 gauge). Not very impressive results. I used cut paper taped directly to the copper. Nothing else - no "sandwich" as I have read about. Can anyone offer some tips on getting the maximum (or even acceptable) depth/strength out of my imprint?