Can't get the right colors when shooting art. Looks pale even with ColorChecker Passport

Fluorescent lights have a spectrum significantly different from sunlight and/or incandescent light. Wall paints are composed in a manner where they maintain their visuals pretty well.

Art paints, however, contain very vivid pigments that have narrow spectral responses. An incandescent light source produces a continuous spectrum (like sunlight does) and will catch those narrow spectral regions. The spectral composition of fluorescent lights, however, is mixture of line spectres and fill-ins. It may appear identical to the human vision but not so to the very narrow-minded painter pigments.

You can check this visually if you have a prism of suitable material for creating a rainbow on paper. With an incandescent light source, the resulting rainbow will be continous. Fluorescent lights will tend to produce significant banding.

My advice would be to try sunlight and see whether this makes a significant difference. Another option for testing is to try a flash (a UV suppressing filter for the flash might be worth a try of you fear for long-term color stability, but then it doesn't sound like you'd be doing this for days on end).

If either makes a significant difference after color calibration, there might be a point in trying to get a hold of incandescent light bulbs, possibly halogenous ones (they burn hotter and thus are a bit more similar to bright sunlight).

Or check your paint supplies for other options: it's not like one can avoid fluorescent and/or LED lighting in future, so some paints might be more suited for indoor exhibitions than others.

The idea pointed by user94588 is very probable to be the cause. If you search in Google for CFL color rendering, you'll find it's usually poor.

But I'd like to add another possible cause, given that I also use Nikon bodies. Lightroom doesn't work well with some Nikon bodies, it ignores some data or parameters. We were working in an art project with colours and crystals/water. Lightroom wasn't able to popup all the colours. We were dubious about the results (the more we tried to retrieve colours the worse it got) and a friend of us tried with other raw processor he had installed. Colours were vivid and crisp with not much difficulty. You could give a try to shareware or trial version of some new raw processors and see.

Álex.

As a printer I see a color cast in shot examples two and three. It looks like your are oversaturating and warming the entire image for the sake of one area.

The white balance looks good in that first shot. I don't think the balnce is the issue. Since you are shooting RAW, I suggest using the first photo and selectively adjusting Red and Yellow during post processing. Don't adjust the entire image. You can save your adjustments as a custom or preset in most softwares.

You may also want to shoot your white card and save your white balance adjustment for post processing. This way iot will not be affected by stray light. The camera sees thet whole card but software sees what you point at.