Negative Supply 4x5 Light Source Basic MK2 (97 CRI)

I used a Minolta CS-100A Chroma Meter (target diameter ~1.5 cm) to measure the brightness and color uniformity of my 4x5 Light Source Basic MkII. My first set of measurements were of two regions: one approximately 1 cm from one corner of the light source, and the other in the center. I made these measurements within ~15 seconds of turning on the light source for the first time after receiving it, after one minute, and after 5 minutes. I made these measurements because drifts in either intensity or color could be an issue despite short individual exposures because I'll be using this light for piecing together two 1:1 images from 24×65mm Hasselblad XPan negatives. I found that drift in intensity, if any, in both regions I measured, over the 5-minute time range of my measurements, was less than one-tenth of a stop, and drift in color was no more than 0.001 on the 1931 CIE color scale. The latter means it would be at the limit of human perception. I bought this light source for digitizing negatives from my Hasselblad XPan, so I next centered my Negative Supply negative carrier with panoramic mask on the light source to determine the properties over the area I cared about. I found the color was uniform everywhere to within 0.001, and the intensity varied within that area by approximately 0.2 stop. I repeated the measurement over an area of 6×9 in case I ever decide to digitize medium format film, with the same result as for the panoramic 35mm mask. However, near the edges of the 4×5 light source the intensity variation was larger, with the maximum difference of 0.65 stop. As for the color of the light, the meter shows it has an effective color temperature of ~4000 K and is only 0.004 units from the Blackbody line, consistent with the manufacturer's claimed high CRI and TCLI. Because of its neutral color as well as the spatial and temporal uniformity of color and intensity, it will serve as an excellent base for digitizing my XPan negatives, as well as 6×9 negatives if I decide to do that in the future. I am very happy with this purchase.