As I always look for ways to improve the quality of my photographs, I found this great tutorial. It is more complex than one would need but it helped me understand how professionals get that beautiful gradient background.
So far I achieved this effect on some of my pieces using Gimp (equivalent of Photoshop in Unix). You cut out the image of the piece and add a gradient background layer to it. It just takes too uch time and adding shadows make it look less natural.
All the credits go to