I had been working with ATC’s/ACEO’S for a short time and really enjoyed it, but didn’t keep it up for very long. These cards were done with bees wax and crayons. The ATC’s measure about 2.5″x3.5″( size of playing cards) and are meant to be traded. ACEO”S which stands for Art Card, Editions and Originals. They measure the same as an ATC but these are sold like miniature pieces of art work.