The darkest in a set of four opaque neutral gray inks ranging from 20%, 40%, 60% and 80% of black on the value scale. Color artists will love the neutral grays for toning down any color without a having a shift in color hue. Ingredients: CAS #7732-18-5 Distilled Water (Aqua) CAS #13463-67-7 – (CI-77891) CAS #1333-86-4 – (CI-77266) Artistic ink, NOT for tattooing.