A carbon dust drawing is like a miniature, extremely detailed, charcoal drawing.  The dust is obtained by scraping carbon pencils on fine sand paper.  It is applied to a substrate of paper, clay, or mylar film with watercolor brushes.  The photo-realistic appearance of the drawing is achieved by brushing the dust to make smooth gradations from white to very dark gray.  White areas are recreated with a kneaded eraser, or cut in with a sharp blade as a final step.  Very dark details can be drawn with a sharp carbon pencil point, or even with ink, again as a final step. The process of drawing involves a constant struggle against the natural tendency of the dust to turn everything in the drawing to a medium gray.  Dark areas have to be continually deepened and high-lit areas recreated as the drawing progresses.  But this plasticity is also the great advantage of carbon dust – it allows almost infinite changes to be made during the course of the drawing, and it makes possible the smooth gradations that create the illusion of photographic reality.