Light output. The Acer H6510BD is bright. At its brightest, in fact, our test sample measured 2524 ANSI lumens with the lamp at full power. Even eco-lamp mode, with its extended lamp life, puts out 1856 lumens in Bright mode -- 74% of full power output. Bright mode's color is undersaturated and pushes blue/green, while black level suffers, but Bright mode can be useful in a room with high ambient light where those factors matter less than pure output.
Standard mode, which has a more balanced image than Bright mode, produces 1844 lumens with the lamp at full power. Standard mode's black level and shadow detail are better than Bright mode, while color shows less of a blue push though green is still overdriven.
By default, Movie mode is the projector's best film and video mode. At 1336 lumens with the lamp at full power, Movie mode has the best default white balance of any mode, though it is still several hundred degrees off from 6500K. Our final calibration for film and video used Movie mode as a starting point and measured almost exactly 1300 lumens post-calibration. In a darkened theater, that is more than enough to drive even the largest screens up to 140" diagonal and above. But the H6510BD really shines in a room with some ambient light, where that extra lumen output can help defeat ambient light and still produce a bright, satisfying picture.
While none of the pre-calibrated image modes are appropriate for large screens, you can also reduce light output by 52% by disabling BrilliantColor in the projector's Advanced menu. If you have a small screen and a light-controlled room, this can help bring the projector's brightness in line with your needs.
Contrast. The H6510BD's black level is deep enough to create a satisfying picture. However, this does not mean that it is the equal of projectors many times more expensive, which benefit from better internal light control, auto iris systems, and higher-contrast chips. Black level is comparable to other entry-level 1080p projectors. Shadow detail is well-defined, and deep shadows in the very low range are still rendered cleanly.
Color. The H6510BD has three preset color temperature settings: CT1, CT2, and CT3. CT2, which is the default in Movie mode, is the most accurate of the three, but red is still under-emphasized while green is pushed. Folks who don't mind fine-tuning their projectors will want to switch to User mode and make adjustments from there.
On our test sample, the following settings produced a grayscale of roughly 6500K:
Color gamut is another story. The H6510BD's color gamut needs work in order to bring it in line with the Rec.709 standard. Unfortunately, the H6510BD's color management system uses very coarse adjustments and it can be difficult to make small adjustments.
On the subject of BrilliantColor, it is usually a good idea to disable BrilliantColor to get the most natural, most balanced image possible. However, it is difficult to calibrate the projector to 6500K across the board with BrilliantColor disabled, so some users will opt to leave it enabled.