  Extending a computation which appeared recently in hep-th/0301173, we compute
the transmission and reflection coefficients for massless uncharged scalars and
gravitational waves scattered by d>=4 Schwarzschild or d=4 Reissner-Nordstrom
black holes, in the limit of large imaginary frequencies. The transmission
coefficient has an interpretation as the "greybody factor" which determines the
spectrum of Hawking radiation. The result has an interesting structure and we
speculate that it may admit a simple dual description; curiously, for
Reissner-Nordstrom the result suggests that this dual description should
involve both the inner and outer horizons. We also discuss some numerical
evidence in favor of the formulas of hep-th/0301173.
