First, get a kid. I recruited mine to model this for you. It helps if they like to be messy. I recommend either a smock or clothes that can get dirty. On both of you, actually.
|We picked some from the woods across from our house, but any leaves will do.|
|Rolling, rolling, rolling!|
|Place them at random, or make a little picture, like from Leafman|
Put leaves all over it, vein side down. Also works well with ferns, salad greens, dandelion greens, and flowers too.
|Doesn't matter that his fingers are inky and smearing, this is the back.|
Put a plain ol' piece of white office paper on top. Rub the back with flat hands over the entire surface.
|At the bottom right here is the negative of the print- the leaves are white, because the ink didn't touch the paper there.|
Peel it off. Voila, the "negative" of the image, at right. Repeat again if necessary to take up most of the ink. THEN remove leaves, and put down another piece of paper, and again, rub the back thoroughly.
Peel, and be wowed. This is the "positive" of the image.
Try displaying them side-by-side for best effect. Mat on 12x18" piece of construction paper and it will give you a tidy colorful border that ups the professional looking quality. Try different colored inks rolled together. Do it with kitchen herbs, like basil and chives. Do it with flowers, or all oak leaves. Use leaves to design a little person, or an animal.
I did this with a whole grade level at RES, taping acetate to tables in the classroom. Connect it to science and life cycles, farm-to-table-to-art-room garden discussions, or to literacy like Lois Ehlert's Leafman.
Feeling ambitious? Grow a garden with your child and have them collect leaves from the plants they would need to make, say, pizza sauce, and arrange those tomato, basil, and oregano leaves in a round composition.