A J Ludlow Dioxaine Violet Professional Watercolour

Dioxaine Violet 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.

Dioxaine Violet Professional Watercolour is prepared using the organic pigment, 8,18-Dichloro-5,15-diethyl-5,15-dihydrodiindolo(3,2-b:3',2'-m)triphenodioxazine (as given on the website of US National Library of Medicine). The pigment has been selected for its purity, high tinctorial strength, light fastness and very attractive, bluish-violet hue, making it ideal for use in A J Ludlow’s Professional watercolour range.

In 1928 a patent was filed by Researchers at the German Chemical Company, Hoeschst, detailing the synthesis of C.I. Pigment Violet 23, which up until the end of the Second World War, was only used to process diamine light blue, a direct dye for cotton (from the article published on 15 march 2009 on Paint & Coatings Industry website).It wasn’t until 1953 that the pigment, started to be used in its own right and in combination with phthalocyanine blue pigments to produce lightfast reddish blue shades (from “The Origins of Colour”, page 20).

The pigment is a member of the dioxazine class of organic chemicals and as such has many of the inherent properties of an organic pigment. In general, organic pigments tend to have relatively smaller particle sizes and larger surface areas than inorganic pigments. giving them a tendency to have higher tinctorial strengths (the strength of the colour increases with decreasing particle size) and be more transparent (as the smaller particle size scatters less light), which can affect the cleanness of the resulting watercolour’s ability to “lift-out” and so watercolours based on organic pigments have a greater tendency to stain. The structured consistency of the highly pigmented Dioxaine Violet, like the other watercolours based on organic pigments in A J Ludlow’s Professional Watercolour range, is due the pigment’s relatively larger surface area, which absorbs more liquid binder, thus affecting the watercolour’s rheology.

Website of US National Library of Medicine accessed on 16/20/20: https://pubchem.ncbi.nlm.nih.gov/compound/C.I.-Pig...

Website of Paint & Coatings Industry (PCI) accessed on 22/10/20: https://www.pcimag.com/articles/88747-pigment-viol...

Geißler G, “The Origins of Colour, The Development of Organic Pigments”, Hoechst AG Publication

Pigment Details: Carbazole Dioxazine / Colour Index Pigment Violet 23 ( C.I. PV23)