Great, thanks a lot !

I currently have my eyes set on the L130-5780002011001 with 5700 K and a minimum CRI of 80%. CRI is something new I found:
https://en.wikipedia.org/wiki/Color_rendering_index

Of course, two parameters are still a very course approximation of the actual spectrum. But you'd probably need serious lab equipment to determine that. (A comparison between two LEDs would be easier, though, since any systematic errors of the test setup would affect both measurements in the same way. Joerg suggested using a prism. You'd still need a proper lab setup, though, if only to make sure the geometry doesn't change between tests.)

- Werner