  Greybody factors in black hole physics modify the naive Planckian spectrum
that is predicted for Hawking radiation when working in the limit of
geometrical optics. We consider the Schwarzschild geometry in (3+1) dimensions,
and analyze the Regge-Wheeler equation for arbitrary particle spin S and
wave-mode angular momentum L, deriving rigourous bounds on the greybody factors
as a function of S, L, wave frequency (omega), and the black hole mass, m.
