> HI Gerhard,
> I think you were seeing a specular reflection. ...

You may well be right, but the eye+ brain system plays many "tricks*"
which we may not expect. The recently discussed rendering as white for
colour mixes on or near the black body line is one such.

Even our perceptions of contrast and shadings can be greatly
influenced by context and comparative adjacent levels.
eg A data projector used to project a black text on white background
image in a diffuse but brightish daylight lit room may produce an
adequate black to white conrast ratio such that the whites appear
white and the black appears black enough for most purposes. On turning
off the projector and examing the screen up close you can find that
the well lit surface is far from black - a somewhat gray at best due
to the background roomlight. When text is frmed by surrounding this
"gray" with brighter white the brain renders it as black (or much
closer to black that before).


                 Russell
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