The music was inspired by the design of the Pageant Amphitheater at the MacDowell Colony in Peterborough, New Hampshire, which Bray described as a "stunning space" with "intense, powerful energy."
"[1] The work is scored for an orchestra comprising three flutes, three oboes, three clarinets, three bassoons, four horns, three trumpets, three trombones, tuba, timpani, three percussionists, harp, and strings.
[1] Reviewing the world premiere, Norman Stinchcombe of the Birmingham Post described Black Rainbow as "short (...) but spectacular, with a battery of brass and percussion and a demanding role for the orchestra's excellent wind section."
He added, "The hushed opening with muted growling brass was suitably menacing and if the central trumpet ostinato outstayed its welcome the gradual manoeuvre from manic energy to questioning quiet, and the handling of large orchestral forces, was skillfully done.
"[3] Martin Dreyer of The Press similarly remarked that the piece "carried a sense of menace through its 12 minutes, leaning mainly on brass and timpani for its spare effects.