I have no idea what this technique is called, but I stamped the flower stamp in white pigment ink first, then colored them in with Prismacolor colored pencils. I have to say that I *love* the result! Used a bit of clear Stickles for the centers and stamped the saying for a nice thinking of you card.
Stamps: Impression Obsession clear stamps
Ink: StazOn white
Colored pencils, clear Stickles