ATC = Artist Trading Cards and they measure 2.5 x 3.5 inches.
April theme choice:
1. a memory
2. take the element of colour and create
I have been playing with a Yupo-type paper which is the equivalent of plastic! The paint may look gorgeous but getting it to stay on the paper is another matter – it can be wiped off extremely easily. To date I have not completely solved this problem and had to discard two of my ATCs as they smudged hopelessly even after spraying with fixative.
credmayne 
Really terrific. I will try it out and see what happens sometime in the month of April! 🙂