The color space you have set on the camera has no effect on the raw file that will only affect the jpeg file created by the camera and also the embedded thumbnail. You have to apply the Adobe RGB color space when you export a rendered jpeg or tiff file from Lightroom. The option is chosen in the export dialog box. see the screen capture "file settings".
"The color space you have set on the camera has no effect on the raw file that will only affect the jpeg file created by the camera and also the embedded thumbnail."
Ah ! that explains it ! So in lightroom the raw file is in the ProPhoto space and in some cases will exceed the Monitor Gamut. I guess I can test this by shooting a test JPG with Adobe RGB specified & import it to Lightroom to see if the Monitor Gamut is exceeded.
"In addition "Adobe RGB " is a working color space and not a "Monitor Profile" you need to use a hardware device like i1 Eye One to create an appropriate monitor profile."
Thanks, I'm aware of this - I have in fact produced a monitor profile using a Spyder 4 - the Monitor is supposed to cater for Adobe RGB & I have profiled it as such. My confusion arose from thinking that the Nikon would apply the Adobe RGB space to the RAW file.
Many thanks for clearing this up.