I finally received my Just Normlicht Color Master 3 print viewer, with 3 florescent tubes and a viewing area of 23.5" high x 26" wide, and an electronic dimmer. My previous try at a print viewer was a GTI PDV 3ED, with a 17" high x 24" wide viewing area, 2 florescent tubes and electronic dimmer.
My most frequent viewing needs include looking at a a 17" x 24" sheet cut from my printer's 24" roll paper, with 2 different 11"x17" images side by side on the sheet.
I had problems with the GTI, not necessarily the fault of GTI: From my desk viewing position, which unfortunately is not able to be re-arranged, there was a glare across the top of the prints when inserted in the print holder at the top. In addition, I could not lower the prints in the viewer without GTI supplying me with an additional metal plate to make the viewer usable with magnets to hold the print. (They were willing to do that gratis). Also, the viewer was not tall enough to view the sheet in portrait orientation when one or both of the two images on the 17X24 sheet was to be a landscape image, but rotated in orientation to fit 2 images on the sheet.
Measuring the GTI's light with my Eye-One Display 2 colorimeter and the SpectraViewII software, I found a constant 5000 degrees Kelvin with the diffuser on the colorimeter, mounted facing out on the middle of the viewing plane. I don't remember the light intensity in LUX that I measured at that time, but when I adjusted the dimmer such that a softproofed white file matched in intensity to a sheet of the same paper in the viewer, my prints and the softproofed version of my prints on the NEC 3090 produced such a close match that it was eerie.
With the Just Color Master 3, the same glare is present at the very top of the viewer; this is a function of Mother Nature and not GTI or Just. However, I can now move the paper down below the glare because of the extra height. Unfortunately, despite having been told that a 24" sheet would be able to fit vertically in the Just, it misses by about 1/2 inch. But the more important goal of avoiding having part of the prints in the glare zone is happily met. So I will have to learn to turn my head to look at some of my prints...not a big thing.
Putting the colorimeter in the middle of the viewing area, I got readings from about 2500 Lux at the brightest, down to about 150 Lux at the dimmest, settings. This range far exceeds what is needed to match print viewer to display, and gives lots of latitude. More important, the color temperature was read at 4900 degrees Kelvin throughout the range, once the bulbs stabilized. I used a piece of black foamcore rather than the optional side panels to block ambient light from the viewer as well as to prevent the viewer's light from affecting my monitor or eyesight when viewing my monitor.
The viewer is sitting on my cherrywood desk, and the effective color temperature of the viewer shifted between 4800 and 5000 degrees Kelvin depending on what I used to cover the desktop. I might invest in a little bottle of the neutral gray paint that GTI sells, and paint some foamcore or matboard as side panels and desktop cover.
It takes several minutes for the florescent tubes to stabilize after turning the dimmer knob, which affects both the color temperature and Lux readings.
I have not yet had time to set and compare the softproof of an image to a printout in the viewer, and I can't remember how I was able to measure the light coming from the display to the light coming toward the viewing plane in the viewer using SpectraViewII and my colorimeter. Some help here is welcomed.
The monitor is calibrated at 130 cd/m2 at this point, with D65 as the white point and 2.2 as the gamma. The contrast ratio is 350:1. Delta E is .39 for the white point and the Grayscale Delta E is .59. Adjusting the print viewer's intensity by eyeballing a print compared to its softproofed counterpart on the display, the colorimeter measures about 690 Lux in the center of the print-viewing plane. Also, I did not yet see a difference between the GTI and Just print viewers despite the dreaded spikes in spectra, which I cannot measure. So far, on HP Premium ID Satin (a very blue paper) and HP Hahnemuhle Textured Fine Art paper (apparently without OBA's) my colors appear as accurate with the Just viewer as they had with the GTI.
Construction of the GTI and Just boxes is similar and appears to be of high quality although a strip used to shield the person viewing the prints from seeing the bulbs is attached with hook & loop pieces on the GTI but with screws in the Just. I also prefer the flexibility of the Just's magnetic back plate for placing the prints compared with the non-magnetic back panel of the GTI, with only the paper-grabbing device placed at the top of the viewing plane. Using 260gsm sheets of 17" x 24" paper overpowered the holding power of the GTI's paper grabber, as well.
If somebody can provide me with the best way to measure the monitor and print viewer to match intensities (I need specific step-by-step instructions) I will do it and provide the results here.