I'm hoping someone remembers how to do this because I looked and couldn't find anything. I can remember as a kid taking sheets of black construction paper and putting objects on them and letting them sit in the sun for a while and coming back to find faded paper with images on it. Can this still be done with modern construction paper? About how long does it take? Has anyone ever tried this in a large or medium format camera, and if so did it have a wow factor for kids? I want to show this no processing photography trick to a three year old. Thanks for any help you can give.