This is a simple mono-printing technique I learned in my childhood which I suddenly recalled this year and decided to try with my grade 2 students.
Students folded a piece of paper in half and thickly coloured one half of the page with various brightly coloured oil pastels. Once they had filled the page, I gave them a black crayon and asked them to colour over their coloured page as thickly as they could, aiming to have no colour showing through. This is the same technique one would use for scratch art. It seems to need to be black crayon and not oil pastel to work properly.
We then folded the page in half again so that the coloured page was on the left side, inside.
I then had students make detailed observational line drawings from leaves we had previously collected from the school grounds. Once they had sketched the leaves lightly, students needed to ensure they had retraced all their lines in pencil, pressing hard so as to ensure the lines were being printed through on the inside of their page.
Once they opened their page they now had their original drawing on the outside and a positive/negative mono-print of their drawings on the inside.This is one of those fun projects where the kids can't predict the outcome and it seems like magic. It can also work with any drawing.