OK, thanks for your reply.
Setting the white balance can tone the image (actually, this is where I started) but it does not emphasize/suppress particular colours.
I've been thinking of something like taking the exactly same images of the printed colour spectrum under different light sources, analysing the changes in RGB values and applying them on the image in question.
I'm going to experiment a little and if I find an acceptable way, I'll describe it.
Btw. I don't believe that the reverse operation (i.e. restoring the image taken under a high pressure sodium lamp to look like taken under a full and continuous spectrum source) could be done.