Complex sentence: Depending on the intent of the artist, several areas may be scratched out for painting with watercolors or acrylics and further detailing later or may be left blank for a stark black-and-white image.
Split into simpler sentences: Depending on the intent of the artist, several areas may be cleared out for layering with watercolors or acrylics. Alternatively, the cleared portions of the scratchboard may be left blank for a stark black-and-white image.