A J Ludlow Phthalocyanine Green (Blue Shade) Professional Watercolour

Phthalocyanine Green (Blue Shade) is just one of the bright and exquisite Professional Watercolours made in the UK by A J Ludlow. Being based on a single pigment with excellent permanence and light fastness, ensures that this watercolour’s properties are exceptional.

Phthalocyanine Green (Blue Shade) Professional Watercolour is prepared using the synthetic halogenated aromatic macrocyclic organo-metallic pigment, copper polychloro-phthalocyanine, with 14 to 15 chloro-substituents at the 16 peripheral reactive sites on the molecule’s four benzene units. The pigment has been selected for its purity, light fastness and intense bluish-green hue, making it ideal for use in A J Ludlow’s Professional watercolour range.

The phthalocyanine pigments, including C.I. pigment green 7, form a large group of synthetic organic macromolecules, that form macrocyclic ligand complexes and have a lot in common with the polyphyrins (a group of organic compounds that include the biochemicals chlorophyll and hemoglobin).The phthalocyanine’s principle metal ion is copper, although at least 70 other metal phthalocyanines have been prepared. Copper phthalocyanine forms a blue pigment, which can then be chlorinated in the presence of aluminium trichloride to form the green pigment, copper polychloro-phthalocyanine, which is usually a mixture of isomers and degrees of chlorination.

Although the first synthesis, which produced a blue powder bi-product are attributed to Braun and Tcherniac in 1907 and Diesbach and von der Weid in 1927, the pigment was not commercialised until 1935 when Imperial Chemical Industries announce their Monastral Fast Blue, followed by IG Farbenindustrie in 1936 and Du Pont in the late 1930s (Pigment Compendium, page 305), whilst the chlorinated derivative of phthalocyanine blue was first sold in 1938.

Copper polycloro-phthalocyanine has a bluish-green colour which is very similar in hue to Viridian (chromium (III) oxide dihydrate, C.I. pigment green 18) and is often used as a synthetic substitute, albeit in a fairly diluted mixture of pigment and other mineral fillers. In A J Ludlow’s Phthalocyanine Green (Blue Shade) Professional Watercolour, the pigment is pure and the tinctorial strength is very strong and so is best used sparingly when initially mixing with other colours.

Eastaugh N, Chaplin T, Siddall R, Walsh V, “Pigment Compendium: A Dictionary and Optical Microscopy of Historic Pigments”, Routledge, Abingdon 2013

Pigment Details: Chlorinated Copper Phthalocyanine / Colour Index Pigment Green 7 ( C.I. PG7)