I've never worked with Shrinky Dink before and this sounds like so much fun!
How big were the kids' original drawings? How big is the shrinky stuff? How
big is the finished product? Did you order it from Sax? Sorry to hit you with
so many questions! Reply if you have time.
Also, about the background for your digital portraits. What about a very puffy,
cloudy, heavenly sky created with colored pencils or well-blended oil crayons?
Or, an irregular patchwork type background made up of shapes containing
different lines or patterns? Trying to picture the portraits and only guessing
what might look good...at least, I may help you to get the juices flowing!