Ambient Light Rejection Screens

Bill Livolsi, August 5, 2015


EDITOR'S NOTE: This article has been expanded and updated to include eleven current models of ALR screens. Please click here for the new review.) 3/03/16

The Tests

ALR screens aren't meant to be used in ideal home theater spaces. They're meant to bring projectors into rooms where ambient light, white paint, or other circumstances would otherwise make projectors unfeasible. So to test these screens we installed them in a room with a large window and white walls to see how they perform in environments for which they are built. In theory, the projector used for these tests should not matter; all tests were conducted with the same projector and in the same environment. To give you a general idea, we used an entry-level DLP home entertainment projector rated at just over 3,000 lumens and 15,000:1 contrast, and all tests were conducted after the projector had been given an opportunity to warm up for 30 minutes. Our reference white surface, used for comparison purposes, was tested and confirmed to have a gain of 1.0 exactly.

Peak Gain and Half Gain

The three screens in this shootout differ in their peak gain attributes. Higher peak gain means a brighter image when viewed from the center position, but it can also mean hotspots, shimmer in the image, or uneven screen illumination, so higher gain is not always better. Sometimes a brighter projector and a lower gain screen yield a more balanced, natural image than high gain and lower lumens.

In this test, the Microlite F2.0 had the highest peak gain at 1.74, essentially matching its peak gain rating of 1.8. Similarly, the Screen Innovations Slate measured a peak gain of 1.18 in conformance with its spec of 1.2. However, the Elite PolarStar measured a peak gain of 1.55 which is notably higher than its rating of 1.3.

As expected, the SI Slate showed the fewest gain-related artifacts; it had no shimmer worth mentioning and no noticeable hotspots. The Microlite F2.0 did have a slight "oil slick" appearance at times, but there were no hot spots unless you made it a point to stand outside of the ideal vertical viewing area. At this point you might notice a "hot band" -- a horizontal stripe across the screen that's brighter than the rest of the image. Sitting in the proper seating location, you can't see any hot spots despite the high gain. On the PolarStar, there's no oil slick, but there is sparkle at times, which some users may find distracting.

The half-gain angle is the viewing angle at which the reflected image is half as bright as when viewed from the center along a perpendicular axis to the screen surface. A wide half-gain angle is helpful if you want to place seating at wide angles to the screen, as it means people seated in these positions will still see a reasonably bright image.

The Microlite F2.0 screen had the widest half-gain angle by far, measuring 56.5 degrees in either direction. In comparison, the Elite PolarStar (25 degrees) and Screen Innovations Slate (21 degrees) offer narrower viewing cones and therefore appear significantly less bright to people sitting off to the sides. Half-gain angle only measures one side of the viewing area, so the brightest viewing area can be determined by doubling those measurements. Closer to the center is better.

Contrast / Ambient Light Rejection

The easiest way to decide which screen is rejecting the most ambient light is to put them all in the same situation and then measure contrast. We conducted three tests: one with lights off and windows completely blocked, one with an overhead light on, and one with the side window shade open. In all three tests, we compared the screens against a reference white screen in order to judge their ability to reject ambient light. We used the same projector for all tests, and we measured from the ideal viewing angle for each screen.

Dark Room Test. First, a point of clarification: our "dark room" in this test has white walls and a white ceiling, meaning it's not very dark at all. In a properly blacked-out home theater, there should be very little performance difference between an ALR screen and a traditional white screen.

We measured black and white levels on each screen as well as our reference white surface using an ANSI checkerboard pattern. The best performing screen was the Microlite F2.0, measuring 217:1 contrast. The Elite PolarStar and SI Slate 1.2 measured 148:1 and 129:1, respectively, which is not a perceptible difference if you aren't using a meter. The reference white surface measured 86:1. In other words, we saw clear benefits using any of the ALR screens even in a room where the only light pollution comes from reflection.

Overhead Light Test. During the next test, we turned on the room's overhead light. This room is normally used as a library and has a pair of 100W equivalent CFL bulbs in a fixture on the ceiling, giving us enough light to read by without straining our eyes.

Contrast took a hit on every screen, with the Microlite F2.0 dropping to 146:1. This still beat out the PolarStar at 110:1 and the Slate at 92:1, but all three screens did far, far better than the reference white surface at 39:1.

Side Window Test. The east-facing window in our test room has a blackout shade that was closed up until this point. For the final test, we turned off the overhead light and opened the shade, letting in some mid-morning sunlight. This had a dramatic effect on contrast. Under these conditions, the PolarStar performed best, measuring 73:1. The Microlite F2.0 measured 61:1, while the Slate measured 50:1. Our poor, abused white screen, unaccustomed to this much ambient light, measured a paltry 20:1.

Our testing revealed some interesting findings. Given how the Microlite F2.0 performed in the first two tests, we fully expected it to triumph in the third test as well - but it didn't. Instead the PolarStar pulled out a win. This tells us that the Microlite F2.0 material is a great choice when ambient light is vertically offset from the projector, but less effective at combatting side lighting. In a room with strong side lighting, the Elite PolarStar is an excellent option.

Review Contents: Overview Elite Prime Vision PolarStar Microlite F2 Screen Innovations Slate
  Shootout Summary

Reader Comments(6 comments)

Posted Oct 7, 2015 3:40 PM

By Dave

Post a Comment Alert Moderator
I see you're adding more models, but what about some other low-cost alternatives like Silver Ticket readily available on Amazon where many reviews of users are pretty solid. I personally own their white screen and love it, but would be interested in seeing measured performance of Silver Ticket ALR screens against the similarly value-priced Elite ALR screens.

Also are you unable to reveal pricing information because of manufacturer agreements? Would be good to factor in performance against value.

Thanks, great work!

Posted Oct 7, 2015 5:47 AM

By Hector

Post a Comment Alert Moderator
I would love to see how well the DNP and Stewart measure up. I need an ALR now, but it's hard to find a good unbiased analysis like this one. So far, I am leaning towards the Microlite but I prefer the edge free designs. The big frame is a dated design IMHO and doesn't go well with multi-purpose rooms.

Posted Sep 19, 2015 6:05 AM

By Nabil

Post a Comment Alert Moderator
many suppliers claim amazing performances but at the end only experience prooves if that`s true or not. what do you think about Prodisplay`s sunscreen front projection?

Posted Sep 17, 2015 6:03 PM

By Nigel Talley

Post a Comment Alert Moderator
It is the world's best

Posted Sep 17, 2015 4:32 PM

By Peter

Post a Comment Alert Moderator
I use a screen innovations black diamond 1.4 in my darkened home theatre room. It is far better than any white screen I have ever used. Blacks are far better, contrast is far better and the biggest thing, no light bleed onto the walls of the room, so it is a real dark room and feels like a cinema! To say all ALRs are not for a darkened room I feel is incorrect. Slate wasn't around at the time I purchased my Black Diamond, but I have seen it in the same situation...still better than a white screen. Maybe not all ALRs are suited to a darkened room but them some are...

Posted Aug 15, 2015 11:18 AM

By Brandon

Post a Comment Alert Moderator
Do the Microlite F 2.0 have to be shelf mounted, near eye level, for max gain, like the HP screens? Or can it be ceiling mounted to get close to its max gain of 1.8?

Post a comment

Commenting on this article is easy and does not require any registration. Your email address is necessary for you to activate your comment once it has been submitted. It will not be shown to other site viewers. ProjectorCentral reserves the right to remove any comment at any time for any reason. Foul language is not permitted, nor are personal attacks. No HTML allowed. All comments should remain on topic.

Name:

Email Address:(used only to confirm your comment)

Your Comment:

(Enter the numbers as they appear to the left)