These chemicals are used for Cyanotype, a photographic printing process that produces a vibrant cyan-blue print. Potassium Ferricyanide is a light-sensitive iron salt; when you add it to any natural surface, including cotton, linen, silk, canvas, wool, paper, wood and leather, it enables you to create a dynamic composition.Details:Available in multiple sizesNatural materialsWater-based solutionSafe to handleFor cyanotype printing