The entire area surrounding the bulb is covered with a silvery mirror like surface that is stated to reflect a very high percentage of UV light. The shape around the bulb is similar to that of NuArc 26-1k or 1ks, but the reflecting surface is very different.
The width of the vacuum frame is 28 inches. That is, the maximum width of paper you could put in the unit is 28 inches. I will be conducting tests soon to determine how much light fall-off there is from the center to various other spots in the frame. That figure with my NuArc 26-1k was about 1.5 stops, for a slightly shorter distance.
BTW, thanks very much for the sheet of ND filter you sent me. It has been very useful in calibrating my new Xenon pulse sensitometer.
Originally Posted by Donald Miller