Panasonic PT-AE900U LCD Projector Testing and Calibration
All of the measurements were performed with the projection lamp on its Low setting. tc \l1 "Testing and calibrationOut of the box, I measured the most accurate color temperature with the color temperature control set to +1 (the Before curve in the accompanying figure). While the mid-point of the control produced a respectable result, it was just a bit too warm, particularly at the dark end (6022K at 30 IRE). Because of sample variations +1 might not be best for all PT-AE900Us that come off the line, but the mid region of the Panasonic's color temperature control is more accurate than what we usually see from the "normal" or "standard" settings on most video displays.
After calibration the color temperature was still a little high at the top and bottom of the brightness range, but closer to accurate across the all-important mid-brightness region. The x,y coordinates of the gray scale steps were also more accurate (a maximum of 0.005 deviation at any point from 30-85 IRE after calibration vs. 0.009 before). You might argue, however, that the difference between the pre- and post-calibration figures is not all that large, and you'll get no argument from me. As received, the projector was very well set up. I did note a noticeable hint of blue on a full-screen video black pattern with the Dynamic Iris disengaged, but this disappeared when I turned the iris on.
The red, green, and blue color points were reasonably accurate, with the largest deviation being green, which was too deep and rich. This is very common in today's digital displays. The blue was slightly too purple-blue by measurement, but this deviation was not visible. Of the three primary colors, the eye is least sensitive to blue, most sensitive to green.
Vertical banding, a problem on some digital displays, was also visible on test patterns. But I almost never noticed it on regular video material. Overscan measured less than 1% in either 720p or 480p, but increased to (a still reasonable) 3% in 480i or 1080i. There is a control on the projector to increase overscan. While you won't generally want to do this, a broadcast will occasionally have a white line or other garbage at the edge of the screen, and the overscan control can eliminate it. This control is not available on 480i, but you shouldn't need it with this resolution's 3% overscan. It's not uncommon for our measured contrast ratios to be significantly less than a manufacturer's claims. We measure the contrast after the image has been calibrated and all controls have been adjusted to produce the best picture (with the contrast and brightness controls set to eliminate, as much as possible, white clipping or black crush), not the best contrast number. I measured a peak contrast ratio on the Panasonic of 1553:1 (12.67 foot-Lamberts peak white, 0.010 video black, Cinema 2 mode, lamp setting Low) with the Dynamic Iris engaged, and 668:1 (14.04fL/0.021fL) with it off. Interestingly, the contrast ratio increased to 1940:1 in the High lamp setting, but only because the peak white level increased (the video black level, surprisingly, remained the same).
The range of settings available from the Sharpness control was slightly different with different resolutions, but generally provided too much range on the plus side and barely enough on the minus. For example, in 720p, the steps ranged from -4 to +11, but I never found any Sharpness setting above 0 to be optimum, and more often -3 or -4 worked best, depending on the resolution and the input—I checked both HDMI and component. I could never completely eliminate projector-induced edge enhancement (white lines around sharp transitions) in either 480i or 480p—suggesting that the design brief for the projector assumed you'd always want a little enhancement for these standard definition resolutions. The effect wasn't obvious at a normal viewing distance (about 1.7x image width), but I'd rather have the option of dialing it out.
While the color, as noted earlier, did look very good in day-to-day operation, adjusting the color and tint controls in our usual manner (using the color bars on the Video Essentials DVD and a blue filter) resulted in some rather extreme control settings: +22 on the color and -7 on the tint. While these settings produced a theoretically correct result as viewed through the filter, and weren't as totally whacky as they sound (each step produced a very subtle change) they still resulted in a strong red "push." Repositioning the color and tint controls to center or near-center settings produced a much better subjective color balance. Based on these test-pattern results, something appeared to be askew in the operation of the color decoder. But it did not significantly degrade the subjective quality of the Panasonic's color on normal program material.
Using my AccuPel HDG-3000 test pattern generator, I tested both the black and white and color resolution of the Panasonic in component and DVI, at 480i, 480p, 720p, and 1080i. In general, the 720p HDMI measured best by a significant margin. It had the most extended frequency response (cleanly responding up to the AccuPel's maximum multiburst of 37.1MHz) and the crispest, cleanest definition. The response in 1080i (HDMI) was visibly more restricted on test patterns—good to 18.5MHz, with the response down significantly at 37.1MHz. This 720p/1080i discrepancy is common in many of the 720p projectors we've tested. In standard definition, 480p was better than 480i. In all the HDMI resolutions, the color resolution was about half that of the black and white. This is common and acceptable. The color system used for DVD and HDTV is designed with a more limited color bandwidth, to make use of the natural limitations of human vision.
The component resolution results were similar, though interestingly with a little more color response at the highest frequencies (but not enough in my judgment to be visibly significant). The result at 720p was still the best, but while the 720p response still extended to the highest multiburst frequency, it was not as smooth as the HDMI result (there was evidence of peaking in the response above 18.5MHz).
If the de-interlacer and scaler in your DVD player is a good one, I'd recommend feeding the PT-AE900U a 720p HDMI signal from the player's HDVI output for the best results. (You'll need to switch the player to 480p for 4:3 and letterbox programming, as these aspect ratios are not available from the Panasonic with an HDMI input).