Thanks for the answer - I did not know of this premultiplacation. This makes it effectively the same or very close? Assuming output transparency/alpha is (T1+T2

Thanks for the answer - I did not know of this premultiplacation. This makes it effectively the same or very close? Assuming output transparency/alpha is (T1+T2/2), dividing by this gives the difference I don't quite get your point on interpolation, but I'll look up when I have the chance