A bit of threadomancy here.
As I have just returned to the world of painting minis, I knew I needed a light box for photographing my minis. Yesterday I selected a nice cardboard box to be transformed into a DIY light box.
I also choosed a little box made of a thinner cardboard to quickly create a prototype and see if oven paper diffused light enough. My prototype light box is similar to Fabian's one, but much smaller. I've been experimenting with different levels of light diffusion, and different light sources with their varied colour temperatures; should you be interested, I'll post those pics. The following pic is the one I've taken today using daylight lightbulbs, one of top (25W) and two on the sides (15W). I think I'll need stronger lightbulbs, but anyway I'm satisfied with the result of the light box:

That pic is straight out of the camera, with only resizing and cropping, but no level adjustment whatsoever. I only need to toy a little with the pics on Paint Shop Pro to correct them, and hopefully pics will be even better when I buy stronger lightbulbs.