After I have my students make collograph prints (with pieces of tagboard
glued down), I have them use oil pastel on the printboards (the next week,
after they are dry.) I encourage them to use the oil pastels on the
negative spaces--those areas that are not raised--and leave some of the
printing ink to unify the piece. Then we adhere them to a construction paper
"frame"--using a color that enhances the piece. They are really beautiful.
I do this same method when I have the students make printboards with pieces
of foamboard glued to a cardboard base--oil pastel is applied to the
negative spaces (in this case, it's very important not to try to apply oil
pastel to the foam pieces, as that will make all the ink come off.) I do
this with my K-3 students. Oh--on the tagboard collagraph prints, I usually
have them cover them with polymer medium--it helps keep all the pieces
adhered when they are printing the next week.