Select FLAT objects you wish to print--weeds, leaves, keys, string, lace, a sliced shell, buttons, cutouts, paperclips, a black and white negative, etc...
Remove a sheet of paper. Pin at corners (blue side up) to a piece of corrugated cardboard for support.
Expose to sun until blue paper turns very pale blue--about 2 minutes. Times will vary; do not overexpose.
After removing objects from paper, protect print from direct sun and soak in a container of plain water for about 1 minute. Dry flat. Image will sharpen during drying time. When dry, flatten under a heavy book.