Pretty simple. I took a box, cut an opening and put a powerful light under the box and I put plexiglas over the box so that the light comes from under the objects on the plexiglas. Its better if you use real glass though... And then I shook the windex to get it foamy. The picture is HDR, its actually the result of 5 diffrent pictures taken at diffrent exposurs because the light falloff was way too strong in the bubbles and the light was too close to the bottom of the windex. I also had to make a hood for the light so that it doesnt flare my camera.
