Blockx Cerulean Grey 15ml Watercolor Tube Cerulean grey no453 is semi transparent and non staining, it is a brighter and warmer alternative to cerulean blue Blockx watercolor is made in belgium since 1865 by the blockx family, 5 generations of chemists. Highest quality pure pigments ensure maximum color strength and quality. Rare, tough pigments are thoroughly crushed, then coated in gum arabic and honey. Blockx has no hues, tints, fillers or transient or unstable (non lightfast) colors, such as alizarin crimson for example