FWIW, apparently when the emissiveness of a texture is
set unusually high (10000?), instead of flooding a room
with light, the image simply renders with large white
granules (more nearer to the emissive object) and black
in between them, even when adjusting rays-per-pixel &
resolution, etc. to compensate. That's with photon-
mapping, whereas Monte Carlo remains dark if recalled.
Richard