h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

This is a great article - scholarly, but accessible to the average reader. I didn't see a reference to cobalt blue, which I understand used to be based upon the element cobalt, but is now synthetic.

OK, it's such a huge subject I decided to focus on the two main advances. There's only a passing mention of Prussian Blue for example, the discovery of which predated ultramarine by about a hundred years, mainly because it's a poor imitation of the latter.

Is woad not really blue?

No, woad (Isatis tinctoria) is definitely blue. However, woad is a dye, and an organic one at that too. It isn't a pigment, as it colours the medium (i.e. dirty skin of a foul smelling ancient Brit) directly rather than being suspended in it as particles. Pigments are much more durable than dyes, generally, and much better suited for paintings.

So a watercolorist would be able to paint bright days and happy scenes with anil and woad, but an oil or tempera painter would be stuck with gloom unless he (or the comissioner of the work) were particularly rich?

I've not heard of a watercolorist painting with woad or anil. Pigments are solids which are suspended in a medium (water, oil, etc) before being put on canvas. Dyes are dispersed at the molecular level, in solution. You can mix pigments on a palette to the desired shade and consistency. Not so with dyes, I understand. If you want some more info drop me an email (it's on my personal space).

Hullo Felonious
I could not let this entry go by without a hearty congratualtion. This is by far a well written entry and I am veryy happy you got editor's pick on it. Very clear and well researched. I wish I was still a monk and could have been the one to submit this one!
!

Thanks for the nice words there. I thought about this article a long time before I wrote it, which I suppose is why it turned out quite well.

I had no idea you were a monk. Do enlighten me more.

do you kn wo how when you are thinking about something in your mind and things come out the wring way. I surely meant scout. I pologize for th econfusion. yes, thinking and planning out an artical really seems to help.

Happens to me all the time. Especially when I'm talking to somebody about one thing and writing about another.

once i was instant messaging someone and we were talking about crosscountry skiing. i was idly immagining skiing naked... I said, something like are going going skiing nakeg tommorow, my fingers just wrote what i was thinking. i hit enter before i realised what i had done... luckily there was an error so it was not obvious what i intended!