Yep...that did it. Custom white balace fixed the problem. I got a faithful and accurate overall tonal balance with this setting. Thanks Graham!
But, what does it say about the camera's overall automatic metering?
Is this normal, that it can't get accurate colour rendition on its own - in this particular case, at least?
Are all camera brands alike in this respect? D200/D300 better?
Is, for instance, spot-metering more accurate in this regard than the evaluative metering I've been using?
Is there some sort of setting-up in the camera that I don't know about? Or is this simply part of taking photos, and "working the gear"?
I think I might have found some answers. Please correct me if I'm wrong:
1. The calibration of my Comp monitor is probably not 100% accurate. The same can probably be said about the Nikon's lcd display, which is not intended for such a precise task. Only on a properly-calibrated monitor (i.e. with Spyder) could one say with certainty that the tonal balance is off.
2. Colour temperature of an object is not only subjective, but also is dependent on numerous variables that cannot all be possibly taken into account (humidity, air temperature, etc). The Nikon allows precise calibration of WB presets (pp.58-59 of manual) an also allows custom-setting of WB (p.60). In my case, colour temperature of WB presets needs to be increased slightly using the sub-command dial while holding the WB button, or by choosing the colour temperature setting (K) and increasing its value to push the blue tinge. Alternatively, choose Custom WB.
3. "Work the gear", read the manual. All is good with the camera. Be happy that it does
have so many options to choose exactly the right colour that one wants