Bright Nautical Duncan Concepts Underglaze. Available in 2oz & 8oz. The concept is simple: colour selection is easy with Duncan® Concepts® Underglazes! These underglazes offer a multitude of vibrant fired ceramic colours in a balanced palette of compatible hues in light, bright and dark options, making colour selection easy – whether it’s your first time or your hundredth! Concepts Underglazes have a versatile formula that allows for translucent designs with one coat and solid coverage with three. They’re also nontoxic and food-safe with the application of three solid coats or when food-safe clear glaze is applied over them. Concepts colours work beautifully with other Duncan products, including French Dimensions™, Satin Glazes®, Crystals™ Glazes and Courtyard™ Art Glazes.