[Radiance-general] Luminance variation with distance

[Carsten Bauer]

Hi again,

just one more short contemplation on the matter: In order for something
to appear in an image, obviously the minimum drawing size is a pixel.
This means if far away tiny sources are to be drawn in the image to
generate a vivid impression, they have to be spread out over a larger
area, say, e.g from a quarter of a pixel to a full pixel. In order not
to exaggerate, it makes sense to reduce the luminance accordingly. Now,
the necessary amout of "spreading out" increases proportional to the
square of the distance, so the luminance has to decrease accordingly,
which would explain your observations.

-Carsten