[Radiance-general] Talk: "A Decade of Radiance Tricks"

[Thomas Bleicher]

On Sat, Apr 9, 2011 at 10:28 AM, Mark Stock <mstock at umich.edu> wrote:

The squaring of the result is to push the values down closer to zero. Most
> of the interesting colors are in the 0.2 range, and that's just a hack to
> get closer. I am sure there's a better way, but that's easy to remember and
> quick to compute.


Your informal way is actually quite accurate. The Photoshop RGB values are
intended to be displayed on a screen with a non-linear response curve.
Radiance uses a linear color space and to convert it you have to apply a
"gamma correction" to the color components:

r = R^gamma
g = G^gamma
b = B^gamma

The typical gamma used today is 2.2. So your simple square is not that far
off.

Regards,
Thomas
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