A great all purpose white card 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. You can display them yourself as wall art or create a wonderful coffee table book with all original artwork. Search ACEO to see all kinds of these cards from many creative artists. The cards measure 2-1/2″ x 3-1/2″. Other than that pretty much anything goes. Affordable-Collectable-Tradable.