The Pouch stops bleeding and makes printing crisper with all sorts of different brands and types of inks. We were astounded at the results of permanent fabric markers when we wrote on polyester twill tape; those Marvy Uchida pigmented, permanent markers are sold for writing on fabric!
We use our regular markers (i.e. ZigTM fade-proof, archival, non-bleeding Writers and TombowTM Dual Brush non-bleeding, water-based markers) to get bold, crisp results equal to specialty vellum markers.
A customer emailed us her results of using the Pouch with CopicTM Markers because she was excited at how it stopped the notorious bleeding carmine red alcohol ink on non Copic-friendly papers. See darker, richer writing with gel pens on vellum as well. Again, experiment and have fun!