Hello Suz. The thickest paper the ET-5150 can print on is Epson Premium Photo Paper Glossy which weighs 79 lb. For cardstock, we recommend using paper that weighs around 44 lb. You can try a cardstock paper that falls in between that range or higher. 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.