I discovered Embossing Powder when I was working on my daughter's wedding invitations this past Summer. We used a rubber stamp of a tree as the theme. Turns out, when the ink is wet, this fabulous powder will adhere to the design, and when heated, bubble up into a nice texture.
(I especially like the metallics) Embossing powders come in a variety of colors, are inexpensive, and can be found easily in the Stamping or Scrapbooking isle of your local craft store. (Don't forget your coupon!)
Of course, you will understand that the creative part of my brain frowned at using a "rubber stamp", but I still wanted to use this in my artwork in some way. Sooo...
During my trial and error, I discovered that a little diluted Gum Arabic and a liner brush work best for "drawing" your design. The gel glue I used in the painting below was difficult to get small enough
Work in small sections with the gum, and sprinkle the powder liberally on the area. then tip it up and tap off the excess. The powder will only stick to the wet parts. I use the lid to an old box lined with a sheet of typing paper to catch the extra, and put it back in the bottle by making a funnel with the paper. A little goes a long way!
There is a heat gun that is like a small hairdryer to melt the powder to the paper. Then you can proceed to paint as loosely as you wish, because your highlights are saved.
I am thinking it may also work on a finished painting to "pull out" a highlight, so I'll have to let you know on that one. :)
I think it is important to share our process with others, just as we gain from watching other artists work.