This listing is for 10 blank ATCs made from scraps of fused billboard vinyl. You can choose to receive light, dark or mixed packages according to what I have on hand. Since these are made from billboard vinyl scraps and offcuts, most will be solid colors that are perfect for painting or collaging. Fused billboard vinyl can be decorated with acrylic paints, paint pens, permanent inks, and any other media that is suitable for plastics or vinyl. I've found that a few seconds with a heat gun will help to "set" your artwork into the vinyl. You can also cover your ATCs with your own papers or collage materials. PVA, Mod Podge or gel medium will work great, again a little heat exposure helps. To add bulky items directly to the fused vinyl, E-6000 does the trick if you let it cure overnight. And the answer to the gesso question is yes! You certainly can gesso your vinyl ATCs before you decorate them. Fused vinyl ATCs can be used in the same way as traditional cardstock or paper trading cards but their unusual feel kicks them up a notch! They're great for collecting, trading, making pocket letters, using as gift cards or tags, sending as RAKs or happy mail, etc. ATCs measure 2-1/2" wide x 3-1/2" tall. Each vinyl ATC is measured and cut individually by hand so there could be a slight variance in those measurements but it will not adversely affect your ATCs.