Op 17/05/2021 om 12:40 schreef Bald Eagle:
> Thomas de Groot <tho### [at] degrootorg> wrote:
> 
>>> I'm thinking that my suggestion for
>>> #local not_0 = 1/256;
>>> was close, but that would not give a pure black.  Maybe 1/257 to give a pure
>>> black monitor color but still not 0;
>>>
>> I think it is a trivial difference. As Alain said, no real black in
>> nature, and the black pigments here represent micas, which are far from
>> pitch black anyway.
> 
> I suppose it is .. trivial ... but my thought was as a general point, we should
> provide the users with the fullest range of colors as possible, realistic or
> not, so that we don't code another 20 scenes that 20 years from now people with
> throw up their hands and cry "Why did they DO *this*???"
> 
> So I was thinking it would allow the representation of the purest black
> possible, but still not be zero.  What color is a dark hole or a lightless room?
> There may also be scenes later on where people are rendering heightfields, etc,
> and want a pixel rgb that numerically is integer 0.
> 
> Nothing really to do with the present granite, just thinking ahead.
> That's all.
> 

I think there are two tracks here to consider: (1) the use of 'pitch 
black' in pigments and textures, where the use of 1/256 or 1/257 would 
be the way to go; (2) the use of <0,0,0> in a 'geometrical' construction 
like a height_field or, I suppose, an isosurface or a parametric object 
or whatever, where 'true' zero would be a must. this should be clear 
from the onset in any scene. Height_fields in particular certainly make 
good use of 'true' zero. Approximations should be reserved for 
pigments/textures.

-- 
Thomas

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