Can a black hole be considered as a gray body?

A quote from this paper:

At the precise location of the event horizonthe Hawking radiation is blackbody radiation. However, this radiation still has to traverse a non–trivial,curved spacetime geometry before it eventually reaches an observer and is detected (e.g., an observerlocated at asymptotic infinity in an asymptotically flat spacetime). The surrounding spacetime thus worksas a potential barrier for the radiation, giving a deviationfrom the blackbody radiation spectrum as seen byan asymptotic observer. The relative factor between the asymptotic radiation spectrum and the spectrumof blackbody radiation is dubbed the greybody factor.