Phthalocyanine Pigments: The Science & Story Behind a Modern Colour Powerhouse

From accidental discovery to studio staple — the chemistry behind the most intense blues and greens in the artist's palette.

Jackman's Art Materials · 8 min read

A Brilliant Accident

Phthalocyanine's origins read like a happy laboratory mistake. In 1928, chemists at Scottish Dyes Ltd. noticed a vivid blue contaminant forming during a batch synthesis — an unexpected by-product of a reaction vessel's iron lining. The compound was striking: a deep, pure blue with remarkable stability unlike anything previously seen.

Imperial Chemical Industries recognised the commercial potential immediately. After intensive research, they launched it in 1935 under the trade name Monastral Blue.

Within a decade of its commercial launch, Phthalocyanine Blue had transformed everything from printing inks to automotive paints — and the fine artist's palette.

What Are Phthalocyanine Pigments?

Phthalocyanines are synthetic organometallic pigments. At their centre sits a metal ion — almost always copper — held in place by a ring of four isoindole units. This architecture allows even a tiny amount to produce intense colour. Benefits include:

• ``` High tinting strength — a little goes a very long way.
• Lightfastness — colours remain stable for decades.
• Semi-transparency — ideal for luminous glazes.

Shades & Variants

Phthalocyanine Blue — PB15

Phthalocyanine Green — PG7 & PG36

The Synthesis Process

Always add Phthalo last. It is far easier to add more than to correct an overpowered mix.

Explore Our Phthalo Collection