Dying & face-up:
The white version of this material is a little bit like blotting paper, and will dye very easily. For dying Rit dye can be used, also alcohol inks. Use a dipping method. Don't soak in alcohol or other coustic fluids or solutions. Let dry thouroughly before the next step.
For face-up, I'd suggest 3 coats of MSC or even a paint-on varnish and then try to do a face-up, relying heavily on acrylic paints. (A method using pastel poweder may not work well.)