The metal embossed trees project is one that I have been doing for a long time. It came up with the project about 10-11 years ago and have done it a variety of different ways. I have found that the best use of the metal is to cut from the roll at 7 1/2 inches and then cut that sheet in half (6 inches). I typically use black paper as the background, but any color will do. I have also learned that doing the border first seems to make for a better picture. I require symmetry on the border, or some sort of balance. I also like for the kids to color in about 80-90% of their border. Once this step is complete and looks nice then they move on to the steps for metal repousse. I have the students draw out their image of the tree, foreground and any hand drawn details for the background. Once they are done they get they're embossing tools and layer their image on top of the metal and foam. Once the image is traced into the metal and then retraced directly on the metal, the kids can start working the metal from both sides (of course being carful not to put too much pressure and make holes). Once they are done and I can see the metal has enough definition, they can use texture plates to add details for the background. The final step on the metal is to add color with sharpie. Below, you can see a couple different examples. This top example we rubbed India ink into the creases, but on the artwork below we skipped that step.
The project is sometimes done with realist or exaggerated realism. Other times we do fantasy trees or even specific fantasy trees, sports related, trees with different shaped leaves, candy themed trees, and sometimes I leave it open and let them choose. I like the diversity of the project and this one always gets noticed at art shows. You may notice this project is also on the cover of my page. :)
This is a very time intensive project, I would allow up to 6 weeks for completion of the background and metal. This is done with 5th graders.