Developed by Sennellier & Pablo Picasso. Sennelier Artists Oil Pastels contain more pigment than any other brand. Use on a variety of surfaces including canvas. paper. metal. wood. stone. even glass. Create multi-media effects over oil. acrylic. pastel or watercolor. These pastels can be thinned with turpentine are lightfast non-toxic and acid-free to resist drying. Choose from 120 open stock colors.