NS-91 Ninja is a smooth moderately dense blue based black. It is well suited for sculptural applications and blown work. It is creamy and works easily, making it a welcomed addition to the palette of blacks from which to choose. When working Ninja, do so in an oxidizing flame. In a reductive environment it will develop gray streaks on the surface and result in a dull matte finish. When applying the color, do so gently. After it is melted in it can take a lot of heat. Ninja is great in combination with many colors and serves as a background for striking colors. Be sure to try layering your favorite Amber/Purple over the surface.