Rejects ambient light. The main draw of a screen like the XS850E is its ability to cancel out the effects of ambient light. Judged on this criterion, it is a resounding success. Lights above or to either side of the screen had little to no effect on dynamic range or black level. Light coming from the same direction as the projected image tended to cause a little bit of black washout, but the poorly-directed ambient light did not reflect as completely as the highly focused light coming from the projector. So, even in this worst-case scenario, the XS850E fabric performed better than a white screen.
Higher contrast, deeper black. The XS850E's relatively low 0.85 peak gain gives projected images a deep, inky black level, while the screen's ambient light rejection boosts dynamic range by preserving low-end shadow detail. This contrast boost is not limited to times when there is a lot of ambient light -- the contrast boost was evident even with the lights out.
Wide viewing angle. Screens work by reflecting light back towards the audience, but the mechanics of that reflection can vary. A screen's reflective properties are quantified as gain.
Assuming a projector mounted perpendicular to the horizontal center of the screen, every screen will appear brightest to a viewer seated along that same axis -- centered, and at a right angle to the screen surface. The diagram below illustrates this concept. By measuring a screen's brightness at this position, you obtain what is called peak gain at zero degrees viewing axis or simply peak gain. Peak gain for the XS850E fabric is listed as 0.85, and our in-house testing returned a value of 0.82. Compared to a pure white 1.0-gain screen, the same image on the XS850E will appear 82% as bright when viewed from the ideal position.
A viewer seated along the blue line will see the image at maximum brightness.
Every screen will appear dimmer to a viewer at a wide angle than it does to a viewer sitting dead center. The angle at which the screen appears half as bright as it does in the ideal position is called the half gain viewing angle. We measured a half-gain angle of 78 degrees horizontally and 18 degrees vertically, which matches up fairly well with the specified 85 and 25 degrees H/V listed in the product's specifications. This is excellent performance for a light rejecting screen. In the past, many ambient light rejecting screens suffered from narrow viewing angles, making it difficult to seat any significant number of people comfortably in the ideal viewing area. The XS850E fabric allows viewers to sit in a 156-degree cone while still receiving at least half brightness.
Easy assembly vs. other ALR screens. Ambient light screens aren't like normal flexible screens. While modern ambient light rejection screens are flexible enough to be rolled up and shipped in smaller boxes, they typically have more complicated installation procedures due to their inflexibility compared to conventional screens. Compared to these inflexible screens, the XS850E/Onyx combination is much easier to assemble and mount.
The XS850E screen uses a mounting system wherein semi-flexible plastic rods are inserted into pockets along each edge of the screen. Those rods are used by plastic brackets which stretch the screen to the frame itself, requiring no tools. This is possible because the XS850E material is mounted to a more flexible backing material which will stretch to fit the screen to the frame. The Onyx frame itself does require an allen wrench for assembly, but one is included in the package.
The last ALR screen we reviewed, the Black Diamond II by Screen Innovations, used a rubber band system to attach the screen via holes in the screen material itself. Previous screens have come with a rigid backing, which simplifies installation but makes shipping and handling much more expensive. In comparison to these screens, Draper's Onyx attachment system is much simpler and requires no special tools. And, since the backing material is not used as an imaging surface, you do not need to worry about fingerprints on the material -- a constant concern on other ambient light screens.