The final layers collected and glue washed on. We had to switch from glue brushes to fingers dipped in glue to push on the collections without tearing the fragile tissue paper.
So final ingredient list for first time visitors: Tempera painting on mat board background. Tempera painting on tissue paper. Oil pastel on tracing paper. Shapes and designs cut from wall paper sample books.
Dilute glue wash to layer all the pieces. Interesting bits and pieces -- the torn parts of tissue paper are one form of reveal. The black tempera lines on the tissue paper resulted in a very cool effect, almost floating, while the light colors receded. Some children chose to place the painted side of the tissue paper down and that was interesting. Some areas are more transparent than other others and that is very, very cool.