Am 29.11.2016 um 18:12 schrieb Mike Horvath:
> On 11/29/2016 11:42 AM, clipka wrote:
>> sRGB also defines a host of other things that make matters even more
>> complicated, namely the "image surround", as well three properties for
>> both the "encoding" and "typical viewing" conditions: "ambient
>> illuminance level", "ambient white point" (which is D50, not D65), and
>> "viewing flare". (And no, don't ask me to explain what these parameters
>> mean - I barely understand those myself.)
> 
> EasyRGB defaults to "Daylight". Isn't that D65?

"Daylight" could be D65 - but it could just as well be any other member
of the "Illuminant D series" (D50, D55, D65, D75), each of which
simulates daylight at another time of day, or even illuminant B or C,
both of which were designed as daylight simulations (although that's
unlikely, since these illuminants have been deprecated).

> http://www.easyrgb.com/index.php?X=CALC

Any colour converter that supports a colour space named "RGB" (or "CMY"
or "CMYK", for that matter) without further qualification isn't worth a
rotten bit.

"RGB", "CMY" and "CMYK" aren't colour models - they are colour model
_families_. The minimum additional information required to convert
colours from one of these models into any other model are the colour
coordinates of the primaries, the whitepoint and - since most real-life
RGB colour models don't use linear encoding - the transfer function (aka
"gamma"). Or the official name of the specific member of the family,
which defines these properties via the model's official standard.

For example, "RGB" could be "sRGB" - or it oculd be "CIE RGB", which is
a totally different beast.

> ColorMine uses these values:
> 
> #declare XYZWhiteReference = color <95.047,100.000,108.883>;
> [...]
> 
> Which illuminant does that correspond to? I have no clue, and assumed it
> was D65 as well.

XYZ (95.047,100,108.883) corresponds to xy (95.047,100)/303.93 =
(0.3127,0.3290), which is indeed D65 (presuming XYZ is CIE 1931 XYZ).

(Don't ask me what XYZEpsilon and XYZKappa are.)

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