"Chris B" <nom### [at] nomailcom> wrote:
> To turn up the brightness in an image there are several ways that you'll
> probably find easier.
> You can adjust the brightness of the output for the whole scene using the
> assumed gamma setting. For example:
>
> global_settings {assumed_gamma 0.7}
> Note that reducing the assumed gamma value increases the brightness of your
> scene.

Tweaking the gamma for brightness is a really *bad* idea, as it also messes up
the colors, because it modifies brightness of the color components in a
non-linear way. For instance, when reducing assumed_gamma, full-brightness pure
red (<1,0,0>) will remain unchanged, while full-brightness pure orange (<1,.5,0>
for example) will become more yellowish (though a boost of the green component),
and slightly pale orange (e.g. <1,.5,.1>) will bleach out (through a boost of
both green and blue).

"Gamma" is a parameter relevant for the whole process of creating and later
viewing a raytraced image, *not* individual scenes, and should therefore
*always* be the same for *all* your scenes (unless you're using different
post-processing steps).

POV-Ray 3.7 actually deprecates the parameter, and rightly so, using .ini file
parameters instead.

Post a reply to this message

"Chris B" <nom### [at] nomailcom> wrote:
> global_settings {assumed_gamma 0.7}
> Note that reducing the assumed gamma value increases the brightness of your
> scene.
I know about this but it will influence all the scene.


> Alternatively you can oversaturate the color of individual components.
That's the point.

I have tested yours tips (and warning too) and now I understood better how to
work with colors attribute to improve some object's details. Now I got better
result with my lava light.

Really I had supposed that the individual RGB color always be 1 (and values
greater than 1 truncated).


Thanks Chris.

Post a reply to this message