Great all purpose cards to create Art Trading Cards. These are a medium weight cardstock like business cards. If you are planning to use a lot of water or heavy mediums you may want to look for watercolor paper or illustration board instead. *****If you use only a little water, you can place weight on the cards after you paint and they will flatten.
Information on ACEO: Art Cards Editions and Originals (ACEO) were once only traded between artists as Artists Trading Cards (ATC). These wonderful little works of art are fun for artists to create and affordable to everyone. The cards measure 2-1/2" x 3-1/2". Other than that pretty much anything goes. Affordable-Collectable-Tradable.