Ampersand Scratchbord/Claybord Inks are specially formulated for adding color to Ampersand Scratchbord, Claybord, and other paper scratchboards. These transparent inks leave vibrant color in only the white areas of scratchboard drawings and can easily be scratched through back to white when adding fine details and highlights. When painting back over areas, these remarkable inks do not leave a heavy ink residue. Our inks are pigmented, permanent, and water-based with a bit of shellac to prevent dissolving. For best results, build up the color in diluted washes following the directional lines in the drawing. Other brands of ink can leave heavy residue on the black surface and can be difficult to scratch if not quickly wiped off. It's easy to mix a wide range of colors with only the six base colors in this set. Each bottle allows the ink to be measured out by the drop. For final touch up, apply Ampersand Black Repair ink around the edges of the subject matter to cover any leftover residue and over-painting. Once all the color is in, go back and scratch out the highlights. This will give the forms in your drawing volume and dimension. Add more color where needed and repeat this process until you are totally satisfied with the results.