Higgins Ink offers pigment-based ink colors that remain bright and transparent after drying. Try using them like liquid watercolors for brilliant washes and rich shading. Colors are completely intermixable for a limitless palette of colors. Dropper cap for accurate color mixing time after time. Great for brush, pen or airbrush! Four color set contains black, carmine red, indigo and white in 1 oz. bottles.?AP Seal, non-toxic.