Scientists, statisticians may understand, from this talk, that it’s not just an art-history thing. Note that when Prof. Beeby speaks of ‘indigo’ he means indigotin, the substance, not the plant we call ‘indigo’.
The implication, in the Beinecke essay, that there is no orpiment in the manuscript is important, because its source was in Italy. On the other hand, that pigment lost popularity in European works from about the 15thC to c.1625, after which its use again increased, continually, to the twentieth century – but not invariably, nor everywhere.
The talk proper begins at 4:50, but you might find the introduction interesting too because it describes Prof. Beeby’s qualifications. The end comment brings up the point of pigment-binders.