D is for Dioxazine Purple

Dioxazine purple

When I first threw Dioxazine Purple into Google I was very surprised at the lack of information that popped up. I was thinking, hey, this is my favourite purple, a stunning purple beloved by many artists, why isn’t there a chemical breakdown or a hazard report or a history of the chemical? What the heck is dioxazine?

Well, many thanks to Matisse who took the effort to add quite a bit of information about their paints and kindly mentioned the word ‘carbazole’.

It appears that Dioxazine Purple is the same as Carbazole Purple. Now having said that, I can find many references to carbazole, but very little to dioxazine, and that includes from chemical websites. So I’m wondering if dioxazine is a derived word and not strictly the name of a chemical. In any case, Dioxazine Purple sounds much nicer than Carbazole Purple, and besides, it starts with a ‘D’!

So, Dioxazine/Carbazole, where does it come from?

Coal tar.

It can be created synthetically, but the process isn’t economically viable.

So it comes from coal tar.

It was discovered by Carl Graebe and Carl Glaser in 1872. In its raw state it is yellow, but a key component in the creation of PV23 (Pigment Violet 23 = Dioxazine Violet) which is used  in car varnishes, printing inks, textiles and polymers…and our paints.

Apparently the pigment is so strong and staining that in a more concentrated form it is so dark it’s sometimes used as the pigment in black Indian ink. By the less quality brands of ink manufacturers, that is.

The chemical itself is very closely related to the red and orange  pyrroles (another name we have been seeing on our paint tubes lately). And carbazole isn’t just used for pigments, it has a whole variety of uses, most of which break my brain when I try to understand them (again, I really should have done chemistry instead of physics at school).

Dioxazine purple

So there you have it. A not so exciting origin of one of my favourite colours.

As for the colour itself…it is strong, vibrant, transparent and has a lightfastness rating of II, though apparently it is at the closer to I end of the II spectrum. So good. It is the staple purple of the palette.

And I love it. I really must do more art with it.

Best wishes,

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