How do you use tannic acid and iron nitrate to finish a burled maple stock and achieve contrast in the grain?

Apply a tannic acid solution to the bare stock and let it dry, then apply iron nitrate to form a dark iron tannate compound. Once dry, abrade the surface with fine sandpaper and Scotch-Brite pads to remove the stain from the long grain areas while leaving it permanent in the end grain areas to create contrast. Finally, apply stock finish mixed with a warm amber aniline dye to gently tint the long grain regions.