I was able to perform extensive testing and measurements on both screens and I'm still torn on which one to keep.
The candidates are an 87 inch 1.3 gain Celexon Mobile Professional Plus and a 90 inch 2.2 gain Da-Lite Deluxe Insta-Theater. Calman Enthusiast and an i1 Display 3 Pro were used for all measurements.
With regards to black level, the Celexon wins hands down according to my eyes and my meter. On an all black field, my meter was unable to get a read on the Celexon, meaning that it was below its .001 threshold. The Da-Lite measured .0022. On later readings, they both measured .0022, so not sure what happened there.
As far as brightness goes, with the iris fully closed and contrast at 0 using Film picture mode and HDMI Standard, the Celexon measured at 12ftl on an all white field. The Da-Lite was around 18ftl under the same conditions and seemed much too bright for my taste.
I attempted to perform a calibration on each screen, but I'm positive that the light being reflected by the walls was affecting my readings, as I could not get the grayscale remotely close to linear. Gamma was even worse, as even with the 2.4 preset, it measured around 1.9 in low to medium stimulus, then dipped to 1.0 on high end. I used full fields for measurements, not sure if window patterns are preferred for projectors.
With content, the Celexon definitely had a more plasma like look due to its lower light output (which I prefer). The difference in black level was not as great as I initially thought, as black gets washed out on both screens during medium to bright scenes, which leads me to believe that a grey negative gain screen may be my best bet moving forward. A previous poster mentioned that using a high gain screen like the Da-Lite would make artifacts more visible. Not sure what is meant by artifacts, but I do see dark bands on the middle of the Da-Lite on overly bright scenes, with a white field being the worst case scenario and some bright sparkle like things in the center of the screen.
This should make the Celexon the slam dunk winner right? Well, the Celexon's build quality is not as good as the Da-Lite. It is much more heavier to carry around. The size difference between the two is more noticeable than I thought because I can't get the picture to use up all of the Celexon's screen real estate, as I run out of room on the top and bottom but end up with a one inch gap each side. On the Da-Lite, I can dial the picture up to occupy the entire screen up to all four borders. Further, I can't get the right vertical edge of the image to line up exactly parallel to the right vertical border of the Celexon screen, with the top of the image being about half an inch closer to the border than the bottom inch.
I attempted to get a lower peak light output to 14ftl on the Da-Lite by lowering contrast to -15 using HDMI Standard. Is this an acceptable way to accomplish this? Or is the Da-Lite's peak light output floor limited to what I get with the iris fully closed and contrast at 0? Would switching to HDMI enhanced and lowering contrast help? I'm trying to make it dimmer but not squash my contrast ratio.
If the Da-Lite's floor is limited to simply closing down the iris, then I think I'm going to return both and just use my wall as a screen until I have my own place to able to hang a fixed screen. I found a 0.95 gain grey 92 inch fixed screen from Silver Ticket for $350 ($200 for 1.0 gain grey), which I think would provide much better performance the the two portable screen and better bang for my buck.
Pioneer Kuro KRP-500M
Pioneer Kuro PRO-141FD
Pioneer Kuro PRO-111FD x 2
Pioneer Kuro PDP-5020 x 2