Projection Screen Reviews

Measurements were made while the room was light sealed. All measurements were taken at a distance of 12 feet from the screen surface. Instrumentation included a Minolta CS-200 color meter (NIST certified 12/2014) with a Quantum Data 780 generator and SpectraCal CalMAN 4 software.

The projector was an Epson PowerLite Home Cinema 3500.

After calibration of the projector to the screen, the grayscale Delta E measured on the DarkStar 9 averaged an excellent 1.96, mainly pre- cipitated by an error of 5.22 at 20 IRE (20% brightness) that gave the overall average quite an uptick. Given the Epson’s inability to go com- pletely black, I didn’t measure at 10 IRE and would not attribute this 20-IRE error to the screen. (Delta E is a figure of merit indicating how close the result comes to the D65 (6,500-K) color standard, with values under 3 to 4 generally considered undetectable to the eye.)

Screen luminance and color temperature were measured at the screen center and several target points across the screen, as shown in the chart. For each screen target, the meter was placed 12 feet away and directly head-on and perpendicular to the target point, then moved off axis in the direction indicated by first 15°, then 30°.

Luminance with a 100-IRE Full Raster pattern measured at screen center from straight on registered at 21.67 foot-lamberts and 6,511-K color temperature.

While the Minolta CS-200 is a capable field instrument for the purposes of video calibration, the chart readings are strictly for comparisons. They indicate exceptional uniformity for the DarkStar 9, with virtually no falloff in luminance across the midsection of the screen and modest light falloff in the corners, which may be related to lens capabilities in the projector and not necessarily due to screen performance. Color temperature remained essentially stable at any point across the screen.

The readings from Center position suggest that viewers sitting up to 30° off axis from the sweet spot should see no drop in brightness or shift in color. The Bottom Center reading could only be taken from head on and from a 15° downward angle due to the steepness of the 30° angle from that target point. The dropoff of light down to less than 10 ft-L from –15° downward indicates the screen’s optical filtering in play. Sitting on the floor would not be optimal for viewing such a screen.—MPH