Non-glaze effects for clay

I was checking out the latest outfit Cassie Stephens was sporting on her blog the other day and found her post about clay hearts that had been colored with crayons and then painted with watercolors.  I was inspired by her results and it got me thinking.  My third grade students worked with clay with an emphasis on slab and texture this year.  There are lots of challenges with glazing and firing a kiln full of slabs and I really didn't feel I had enough stilts to make certain we wouldn't have a mishap or two.  I decided to set up stations and give the students choices on how they might complete their work.  Two stations contained tempera paint in neon colors.  By splitting it into two stations I had divided the painters into two separate groups so that they wouldn't be working elbow to elbow.  Another station contained crayons, one oil crayons, and one colored pencils.  The last three stations would all have an India ink wash applied to the final project.  As the students finished, I applied the ink and they removed it under running water with a gentle rub.  So here is the reason for this post,  the ink just didn't have the pizazz I was looking for.  Last year I had done clay magnets with kindergarten, here and had used black tempera paint.  I really liked the way they had turned out and how the color of the crayons seemed to pop.  Tempera is definitely my medium of choice with this technique.  Here are a few finished birds to demonstrate the differences.

Left: Oil Crayon with Tempera
Center: Crayon with India Ink
Right: Color Pencils with India Ink

I may try to paint over the ink ones and see if I can achieve more contrast with the colors...we'll see.