After engraving or sandblasting a glass surface to your specific depth, fill the deep areas with Color Line Paints & Pens. Use the paint directly from the bottle. Smear the paint over the glass surface, making sure to adequately fill the etched areas.
Dry well before removing the overspill with a spatula, squeegee or with your finger tips. This application gives you a sharp colour outline with a strong definition even in areas of very fine inlay.