The unsanded surfaces are papers such as the regular Mi Teintes paper (not the Mi Teintes Touch), Fabriano Tiziano, and Watercolour papers. I just don´t have a lot of luck with those. My winter cottage scene was done on the Fabriano Tiziano paper.
The sanded (rougher) surfaces have a surface similar to actual sand paper. Uart has grit from about 320 all the way up to 800 for fine detail work with pastel pencils and the like. Both my sunflowers and Strelitzia were done on the Mi Teintes Touch paper/board. Premier also makes lovely papers in various grits. Another favourite is the Velour paper.
I prefer the sanded type papers as they hold the pastel much better for me. It´s a good idea to try out various brands and types of paper to see what works best for you.
