Blue has maintained a sacred and often royal status throughout human history, largely due to the scarcity of vibrant and stable natural blue sources. The oldest known synthetic pigment in the world is Egyptian Blue , a calcium copper silicate used by ancient civilizations. For centuries, the preferred source for a deep, pure blue was Ultramarine , meticulously ground from the semi-precious mineral lapis lazuli, which made it famously more expensive than gold during the Renaissance. A radical turning point occurred in the early 18th century with the accidental discovery of Prussian Blue (PB 27), marking the first modern synthetic iron-based pigment. However, the greatest revolution in blue pigments came in the 20th century with the synthesis of Phthalocyanine (PB 15). This group of organic compounds provided unmatched tinting strength, chemical stability, and a pure, brilliant hue, essentially replacing older and more expensive inorganic alternatives in mass-production. Today, copper phthalocyanine blues are the global workhorses of the printing, plastics, and coatings industries, while special inorganic blues remain vital for applications requiring extreme heat resistance and specific high-durability properties.
Pigment Blue 15:0
Colour Description: Strong reddish-blue.
Transparency/Opacity: Semi-transparent.
Pigment Blue 15:0 is the crude, unstabilized alpha (https://en.wikipedia.org/wiki/Alpha) crystal form of Copper Phthalocyanine . It provides a strong reddish-blue shade with very high tinting strength. However, because of its unstabilized crystal structure, it is metastable and has a tendency to convert to the more stable beta form when exposed to certain solvents or heat. This can result in undesirable color shifts. Therefore, it is rarely used in high-grade applications without further treatment or stabilization.
Pigment Blue 15:1
Colour Description: Reddish-blue.
Transparency/Opacity: Semi-transparent.
Pigment Blue 15:1 is the stabilized alpha crystal modification of copper phthalocyanine . Through specific manufacturing treatments, the alpha crystal structure is stabilized to prevent conversion to the beta form. This pigment offers a clean reddish-blue hue, very high color strength, and good resistance to solvents. It is widely used in printing inks, paints, and plastics where a deep, slightly purplish blue shade is required.
Pigment Blue 15:2
Colour Description: Reddish-blue.
Transparency/Opacity: Semi-transparent.
Pigment Blue 15:2 is an anti-flocculating variant of the stabilized alpha copper phthalocyanine pigment. In addition to the stable alpha crystalline form, it contains specific additives that prevent the pigment particles from clustering together (flocculation) within liquid paint and ink vehicles. This ensures superior dispersion stability, resulting in consistent color strength and gloss throughout the application process.
Pigment Blue 15:3
Pigment Blue 15:3Colour Description: Greenish-blue.
Transparency/Opacity: Semi-transparent.
Pigment Blue 15:3 is the stable beta crystal modification of copper phthalocyanine . It is arguably the single most important blue pigment used globally in printing inks (specifically for cyan in CMYK four-color printing), coatings, and plastics. It features a clean, greenish-blue shade with exceptionally high tinting strength, good lightfastness, and excellent resistance to heat and solvents, making it highly versatile.
Pigment Blue 15:4
Colour Description: Greenish-blue.
Transparency/Opacity: Semi-transparent.
Pigment Blue 15:4 is an anti-flocculating variant of the beta copper phthalocyanine pigment. Similar to PB 15:3 in color shade, this particular grade is chemically modified to prevent flocculation in solvent-based and water-based systems. This ensures uniform color development and prevents the formation of agglomerates, making it a crucial choice for high-performance, high-speed industrial coating formulations and premium gravure inks.
Pigment Blue 15:6
Colour Description: Very strong reddish-blue.
Transparency/Opacity: Semi-transparent.
Pigment Blue 15:6 is the epsilon crystal form of copper phthalocyanine . This specific crystalline modification delivers an exceptionally strong, deep reddish-blue shade that is distinct from both the alpha and beta forms. It possesses outstanding color strength and high saturation, frequently utilized in high-quality printing inks and specialized plastics where a deeply saturated, purplish-blue hue is crucial for achieving specific target colors.
Pigment Blue 60
ue 60Colour Description: Deep reddish-blue.
Transparency/Opacity: Semi-transparent.
Pigment Blue 60 is a high-performance organic pigment belonging to the Indanthrone (anthraquinone) family. It is recognized for its deep, intense reddish-blue shade and outstanding lightfastness, heat stability, and resistance to chemicals and migration. While more expensive than phthalocyanine pigments, it is frequently used in premium industrial coatings, high-end automotive finishes, and demanding engineering plastic applications that require superior, long-lasting color permanence.
Pigment Blue 27(Milori Blue)
Colour Description: Deep dark blue.
Transparency/Opacity: Opaque.
Pigment Blue 27 is an inorganic pigment composed of ferric ferrocyanide, widely known as Prussian Blue or Milori Blue. It is one of the oldest synthetic pigments, characterized by its deep, dark blue shade and high tinting strength. It provides good lightfastness and is highly resistant to acids. However, it is sensitive to alkalis and will decompose. Its historic applications include blueprints, artists’ colors, and industrial coatings where alkaline exposure is not a concern.
Pigment Blue 28(Cobalt Blue)
Colour Description: Bright greenish-blue.
Transparency/Opacity: Semi-transparent.
Pigment Blue 28 is an inorganic pigment composed of cobalt aluminate. It provides a distinctive, bright, and clean greenish-blue shade (the classic “cerulean” or “cobalt” blue tone). It offers exceptional heat resistance, chemical durability, and stability under extreme ultraviolet radiation. It is chemically inert and entirely non-toxic. Due to its outstanding stability, it is highly favored in ceramic glazes, artist paints, and specialty high-temperature industrial coatings.
Pigment Blue 29(Ultramarine Blue)
Colour Description: Pure reddish-blue.
Transparency/Opacity: Semi-transparent.
Pigment Blue 29 is an inorganic pigment composed of a complex polysulfide-containing sodium aluminosilicate. It is a synthetic version of the naturally occurring mineral lapis lazuli . It provides a clean, bright reddish-blue shade with a very distinct, pure hue. This pigment is valued for its excellent lightfastness and heat resistance (though it decomposes at extreme high temperatures). It is widely used in paints, plastics, and printing inks, offering a safe and relatively low-cost alternative to genuine ultramarine.
Pigment Blue 36
Colour Description: Blue-green / Turquoise.
Transparency/Opacity: Opaque.
Pigment Blue 36 is an inorganic mixed metal oxide pigment, composed of cobalt and chromium oxide. It delivers a distinct blue-green or turquoise shade with complete opacity and excellent hiding power. This pigment is chemically inert and offers outstanding resistance to extreme heat, weathering, alkalis, and chemicals. Because of these properties, it is typically used in outdoor architectural coatings, high-temperature ceramic glazes, and heavy-duty industrial paints requiring exceptional long-term durability.