I've had a few questions on these. One is how I get the different colors. On the black box (1X1X1m) I built for this I use a flash with a warming gel on one side and a light with a cooling gel on the other. I cut the holes for both of these while making the box. It doesn't work as well with the warming and cooling reversed. I've tried other gels but so far these are the only ones that effectively mix. Oh and black velvet backing and a thoroughly barndoored flash are also important.