Shooting magenta printing ink

[purpleblues]

I took pictures in a print shop recently. One of the shots was of an open bucket with wet magenta printing ink in and around it. All of my raw converters (LR3, C1 5, Capture NX 2, RD and even RPP) showed a solid warm red but no magenta no matter what (at least halfway correct) white balance or what calibration preset I chose. I'm using a calibrated Quato monitor that can display the full Adobe RGB colour space, so the monitor is most probably not the problem. Colour tweaking in LR and C1 brought me closer to what I saw with my eyes but still no real match. Is this again one of those "uncleaned corners" of the LAB colour space (like my "purple blues"-post some time earlier in this forum) or does Nikon's sensor not recognize this colour correctly? Or is it an unsolved problem of camera profiling?

purpleblues

[John S C]

Could the light source have something to do with it?

If you have a MacBeth  Color Checker you could use the profile creation software that X-Rite produce for use with the Color Passport . Although the software is for use with the Color Passportit works fine with the Color Checker. I use it as a Lightroom plug in, and it creates custom profiles for use with Lightroom. I've found it works reasonably well in situation where the surroundings have affected the quality of the light. For example shooting in  rooms that have large areas of warm coloured wood

[purpleblues]

The lighting was the usual flourescent lighting of the same type all over the place. This type of lighting once caused paler reds during a shoot in a restaurant kitchen making the meats look less tasty, but I never saw such a drastic shift from magenta to red. (I also took WB with a grey card.) Since all converters with their different profiles show the same shift I'm starting to think of the spectral sensitivity of the sensor (i. e. the bayer filters covering the pixels) as a reason.

[Salo]

Try to use a supplementary IR blocking filter. Maybe the AA filter is to weak. The sensor have a higher sensitivity in the red/infrared portion of the spectrum and magenta spectral reflectance curve show a high component at the red/infrared end.