Construction was simple. I got two sheets of 20" x 30" foamcore, and cut them down to four 20" x 15" pieces. On three of them, I cut out a rectangle in the center, leaving a 2" border along each edge. I taped the four pieces together (with duct tape, of course) into a long box, and cut pieces from the cutout sections to fill the back. If the foamcore is colored on one side, make sure the white side is on the inside of the box. The open sides were covered with tissue paper cut to size, held in place with double-sided tape.
The box is held onto a cheap wooden tv tray with a pair of binder clips. Two cheap clip-on lamps provide the light; each has a 100W broad-spectrum bulb in it. Position the lamps so they are right against the tissue paper to ensure all the light goes into the lightbox instead of reflecting off the outside.
The backdrop is some light blue construction paper taped to a long piece of posterboard. You can use pretty much anything, as long as it's fairly long and can curve. That curved backdrop hides the corner at the back of the lightbox.
And, last, a cropped image of the figure. Right now I'm lacking a lamp for the top of the box. Placing another light there should take care of the shadows on each side of the figure.
