I like the PortaTrace box and it's easy to carry around but the box I built many years ago still is my best. I made a wood box dadoed for the top and put in two color corrected lights. I got the bulbs at a GE supplier and the top from a plastics distributor. I must have gotten it right the first time. Like Ken with 8x10 negatives a larger box is required. My ideal light box would be two by four or five foot unit on a stand like the commercial photo labs have, or had.