Hello DonnasPrinter. The thickest paper the ET-2850 can print on is Epson Premium Photo Paper Glossy, which weighs 79 lb. For cardstock, we have tested similar Epson paper that weighs around 44 lb. We recommend trying cardstock that falls somewhere in that range. However, your results can vary when using thick or heavier paper, as these recommendations are for Epson paper only since we have not tested 3rd party media. Regards, Kevin - The Epson Team.