I'm not sure why but I decided to do mine in colored sand. After gluing the blank into a stiff substrate, I mixed almost every color from only a handful of different sand colors. I then painted the blank with glue, sprinkled with sand & then tapped off the excess. When I finished every color I then sealed it with an extra layer of glue on top.
Here are some images of the postcard & the process along with the final work...
It's called Gritty Detroit...





If you are interested in learning about Michigan artist Marshall Fredericks check out this article: link. It is a nice overview of his career.
The DAM exhibition opens June 6th and runs through July 12th, 2008. For more information check out DAM.