[Data-modeling] New properties for the "Visual Art" domain "Color" type

[Ed Laurent]

> If we want to represent that sRGB is Crayola SkyBlue and
> #87ceeb is CSS3 skyblue then we have to decide if the name is the
> common topic or the sRGB value is.


Why not have a #80daeb topic of type Color with a "Color dictionary"
property of expected type color_dictionary set as "sRGB", and a SkyBlue
topic of type Color with a "Color dictionary" property of expected type
color_dictionary set as Crayola ? The Color type could also have a property
of "Equivalent color" with expected type Color.

One option might be to have the sRGB topic defined by a particular
> value dominate and then have keys into various namespaces, /color/
> crayola/skyblue


I think this is the approach I described above. Correct?


> Alternatively we could endeavor to take the existing Azure topic /guid/
> 9202a8c04000641f8000000000385053 and add different properties for RGB
> or a compound value type that has the pair, sRGB and color
> dictionary.   I think this was where Faye was heading.


I think Faye's approach is not that different than described above except
that there is extra complexity in the model that reduces the amount of data
entry. The property that links colors would expect a topic(s) of a specified
color dictionary. For example, there could be a property named "Equivalent
sRGB color(s)" with an expected type of sRGB_color that is co-typed with the
more generic Color type.

Your suggestion, if I understand it, is to make standalone topics even
> for the same sRGB triples but to have an explicit property that allows
> people to say that these are the same or corresponding colors?  I
> agree that that would most explicitly capture the arbitrary nature of
> this color matching.


Not quite. There would only be one instance of a topic for any given sRGB
triple. However, the "Equivalent color" or "Equivalent Crayola color"
property could accept multiple values (e.g., SkyBlue, LightBlue).

One difficulty is that there will rarely be truly equal colors because the
color dictionaries have different scales (e.g., 8 bit vs. 32 bit) of
different primary color combinations (e.g., RGB, CMYK, CIE xy). So there is
really a range of equivalence measured in multiple dimensions among *the
spaces between* colors of different dictionaries. The colors themselves may
not ever truly overlap because they are points within the multidimensional
space of the color dictionary. CIE xy and CIE XYZ are colors that will
overlap because one is measured in two dimensions and the other in three
dimensions. If I understand Nick's excellent description correctly, all CIE
XYZ values of a specified X and Y are "Contained by" the color defined by
the same x and y values of CIE xy.

More questions than suggestions I guess...

-Ed
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