Deep bluish-black effect pigments

Deep bluish-black effect pigments, each pigment comprising

• a synthetically produced transparent dielectric flake-form substrate which has a green interference color and a refractive index n of greater than 1.5, and
• at least a layered structure consisting of
• a first layer composed of hematite and/or goethite, and
• a second layer composed of magnetite,
• on the flake-form substrate, wherein the second layer is located on top of the first layer and the first layer is located directly on the substrate;
• wherein the transparent dielectric flake-form substrate is a glass flake having an SiO2 proportion of at most 70% by weight, or wherein the transparent dielectric flake-form substrate consists of Al2O3, of Al2O3 with a content of up to 5% by weight of TiO2, based on the weight of the substrate, or of ZrO2 or of TiO2, or wherein the transparent dielectric flake-form substrate comprises Al2O3, ZrO2 or TiO2 with a proportion of at least 90% by weight. based on the weight of the substrate;
• wherein the flake-form substrate has a particle size of 5 μm to 200 μm;
• wherein the first layer has a geometrical thickness of 6 to 10 nm;
• wherein the second layer has a geometrical thickness of 80 to 230 nm;
• and
• wherein the effect pigments are deep bluish-black effect pigments.