I went to the presentation at the Royal Society last week given by this group on Grosseteste's colour theory. Grossteste's papers are very dense and very short, and this one fitted on a sheet of A4. He had a theory about colour that seems to have three clear axes and eight corners. However, he never tells us what the axes are called, or names a single colour, or even tells us where white and black come, which the presenters admitted was 'pretty strange'. There is no obvious algebra, which is correct for the age, but makes it very hard to interpret an unambiguous meaning. Aristotle's theory on colour, which Grossteste would have read in translation from Arabic at the time, has clear experimental models for generating infinitesimal shades between any two colours, and names seven colours - perhaps in an early attempt to see how many colours are needed to mix any colour. In contrast, it is difficult to be sure whether Grosseteste's work is philosophical (which colours should exist), experimental (which colours do exist), or mathematical (how can we model what we see).
Grosseteste was known to be one of the better mathematicians of his age. He is not Nostradamus, pumping out cryptic statements in the hopes that some of them will match something at random. What he said was respected in his day. We have some modern computer model that seems to match what he said to some extent, but only for some small subset of the parameter space. I suspect this tells us more about how we think then about how Grossteste did.