Am 30.11.2016 um 09:15 schrieb scott:
>> sRGB does /not/ explicitly specify what full red, green and blue are.
>>
>> What sRGB does define is the _xy coordinates_ - i.e. the absolute hue
>> and saturation - of red, green and blue (aka the "primaries"). This can
>> be visualized as defining the direction (but not the "length") of the
>> red, green and blue axes in XYZ space.
>>
>> sRGB also /does/ explicitly define the _xy coordinates_ of the so-called
>> "illuminant whitepoint" - i.e. which defines what colours are nominally
>> "neutral", i.e. entirely desaturated - and also defines that such
>> neutral colours are to be represented by the red, green and blue
>> channels all set to the same value (which is typical for RGB colour
>> models). This can be visualized as defining the direction (but again not
>> the "length") of the RGB "cube"'s diagonal in XYZ space.
>>
>> sRGB also /does/ explicitly define the _Y coordinate_ - i.e. the
>> luminance - of the brightest representable colour: 80 cd/m^2; however,
>> not everyone adheres to this.
> 
> The exact definition may not be as I simplified to, but the point is the
> same. The "output" of the spec is that XYZ for each of R,G,B are numbers
> that are always the same, there is no dependence on some externally
> provided white point information.

You're right in that respect. The above information was mainly for the
records.

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