I also use Solux bulbs, but with the screw base, not MR-16. I print both color and b+w, so I just use one set of lights for both. The Solux allows me to see if there is any color cast to my b+w prints and how toning affects it better than a standard bulb, and os necessary for color prints. They were a little pricey, but I canuse a standard light socket instead of track lighting, though tracks could be used if I had space for them. I like the idea of diffusing them, I will have to look into that.