I have been having SUCH a great time making collages on the most unlikely of "canvases"--flattened boxes! I let the box itself and the paper scraps that I have handy inspire a composition.
My process is pretty simple: I collage over the whole box, letting the paper extend beyond the box's borders, and then at the end I trim the edges. I like preserving all of the funny little intricacies of each box and its various flaps. When finished, I press the collages flat under large heavy books to counteract any warping that happens after collaging.
If you'd like to make box-collages with me, it will be one of 3 creative prompts in the first of my new collage sessions (on Tuesdays, starting on Feb. 23). The series of 8 sessions is called "Collage Community" and you may sign up for as many (or as few) as you like. Each week I will have new collage prompts. We'll work on our collages together, and share ideas and feedback. (Registration = $15, on my website under "Classes")
Shown here are just a few of my collages -- with "after" AND "before" shots to show the transformation from box shape to finished collage.
I got the idea for collaging on boxes from German artist Ina Le. You can see her box-collages under her Instagram name Inflowpapier.