I went to an exhibition at the National Gallery about colours so know all about ultramarine and shit.
The cheapskates who use cheaper substitutes of ultramarine now have their paintings all faded. That's why some of these pictures have odd colour skies ...
And DC and I went to a workshop there too - almost all the children know about lapis lazuli, I suspect from minecraft rather than from the national curriculum.
When they synthesize purple (or was it mauve) Queen Victoria was so taken with it she dressed her entire family in purple.
That must have been a sight.