The lamps I have seen in person have a visible green light reflected off the skin and veins show nicely. So the spectrum is quite variable considering the pic I posted shows red light. It needs to be a spectrum that can penetrate the skin and show what is underneath, but not so deep to show bones or deep arteries etc. So on a broad scale, the spectrum is way above x-rays, and somewhere within visible light or that refracted/reflected by the skin. I assume soft x-rays or the likes could be used along with visible light of some specific colour? But still, to me that makes no sense, as x-rays usually need an absorbent material to display the result of refracted/reflected energy passing through and/or absorbed by the subject. In the case of the lamps, it is definitely reflected light of some sort that one sees. Perhaps simply a high intensity green bulb or red bulb will do, within the visible light spectrum. Anyone who knows what spectrum the vein lamps are produced with, chime in!
^Cool you got an anatomy book. Everyone should have a decent edition of one lying around. Can you give the title and author(s) of the one you bought?