D421is a set of 5 primary colors in 20ml tubes. Holbein Primary Colors offer excellent handling qualities, very high chroma, superlative hues and exceptional lightfastness. Since the density and the handling characteristics are well balanced, mixing two of these colors equally will produce secondary colors easily. Mixing three of these colors equally will produce black and dark grey. Producing a comprehensive grey scale has never been easier.
Holbein has also created a Primary Black and Primary White. These two colors have been produced because, unlike Ivory Black and Permanent White, they offer the same specific gravity as the other three Primary Colors. The result is a set that will produce colors identical in volume and weight when mixed together.