On 2025-08-07 06:24 (-4), Mr wrote:
> The only time I ever use Ambient values are for light generating surfaces. lcd
> screens etc...

This usage is deprecated since POV-Ray 3.7, and if you use radiosity, it
won't work at all.  Use 'emission' in place of 'ambient' for glowing
objects.

> Cousin Ricky <ric### [at] yahoocom> wrote:
> 
>> Diffuse+reflection should be below 1; specular albedo should be
>> comparable to reflection, if you use use specular at all.
> why should we use the same value for specular and reflection when using both?
> Say if we think of emulating a layered material with varnished mirror-like
> reflectivity but a more say oily or smooth inner structure... Couldn't both
> these layers have different shininess?

Because they are basically the same thing.  A highlight is literally the
reflection, blurred more or less, of a light source.

The 'albedo' keyword modifies specular (and phong) so that the highlight
represents the amount of light in its argument.  Without 'albedo', there
is no correlation between the hightlight and the objects reflectivity.

For non-metallic shiny surfaces, 'specular albedo' should be low for
older versions of POV-Ray (I use 0.052 or 0.053 for glass), because
highlights did not simulate the Fresnel effect until POV-Ray 3.8.  With
finish-level Fresnel, the 'specular albedo' value should equal the
Fresnel reflection value.  But for metallic finishes, the 'specular
albedo' value should be the same as the reflection value.

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