Thanks for your comments. This is the way I did:
I bought Don Quijote and Sancho Panza figures in a Tourist Store. Don Quijote is as tall as 16 cm, approximately.
I put the camera just in front of a flash with a softbox. In the middle, I put my figures on a box that was covered by a black cloth (velvet). I measure the light with an incident lightmeter just in the Don Quijote head. It was f/32 for v=1/60. I opened my lens two steps, so I made the photography with f/16, v=1/60. In this way, the light results in a white background and the figures appear completely black.