No, I don't think that's a good idea.  X11 Magenta is completely different from the meaning of "magenta" for centuries before.  I think the X11 guys needed a name for FF00FF, and just picked "magenta" as the first thing they could think of.  I agree it's good to have a source, but the X11 colors aren't a very good source for this, IMO.  We could try converting 100% magenta ink color (maybe like from some SWOP CMYK space) to sRGB using ColorSync or some other CMM, and then source that as the color for "Magenta".  But really this is a reason that I don't like swatches for such articles: "Magenta" doesn't refer to a particular color, so much as a range of colors. jacobolus (t)