A:Answer Hello RgF. The thickest paper the ET-2850 can print on is Epson Premium Photo Paper Glossy which weighs 79 lb. For cardstock, we recommend using paper that weighs around 44 lb, as similar Epson paper is tested to work. You can try a cardstock that falls in that range, but your results will vary, as these recommendations are for Epson paper only. Regards, Syd - The Epson Team.