Note: Our Epson EH-TW9100 review sample was calibrated using Calman Professional, the industry-leading video calibration software. These measurements reflect the projector shooting into the lens of our colorimeter.
|Pre-calibration RGB tracking and delta errors (dEs)|
In the “Natural” picture mode (which, for once, actually is natural, so thumbs up to Epson for the labelling), pre-calibrated images were tinted somewhat blue. The error was not extreme. Due to the default setting of [Contrast], highlights were tinted red.
|Post-calibration RGB tracking and dEs in [Natural] mode|
The Epson EH-TW9100 “only” features 2-point greyscale calibration controls. Fortunately, it also features linear greyscale tracking, so 2-point controls are enough to get very high quality images out of it during calibration. At least, this is the case at the moment – lamps and panels do age, so more precise electronic correction at specific stimulus levels would be a good feature to have. Many projectors do allow 10-point (or higher) correction of greyscale by allowing separate luminance and R/G/B gamma curves to be created. The EH-TW9100 does have a gamma control but it only affects luminance, it can’t be used to precisely influence greyscale mixing.
Regardless, we achieved near-perfect greyscale tracking with our Epson EH-TW9100 review sample. The only visible remaining error was at 10% stimulus, near-black areas were tinged slightly blue. To our eyes, this is a preferrable error over a red or green tinge.
|Pre-calibration gamma tracking (2.2)||Post-calibration gamma tracking (2.4)|
Gamma out of the box tracked linearly at about 2.2. From our point of view of watching in a light controlled environment, this is not the ideal way to structure luminance distribution: in a dark room, the viewers’ irises open up, which is why we generally calibrate to 2.4 (which is the same setting recommended for use in Hollywood mastering rooms, and very close to the natural 2.35 gamma of Sony BVM-series CRT monitors that have been used in post production for decades). We imagine that the gamma of 2.2 has been set for less-than-ideal viewing environments, such as rooms with bright/reflective surfaces, which will wash the projected image out somewhat.
|Gamma adjustment menu|
To achieve our goal of 2.4 gamma, we had to acquaint ourselves with the EH-TW9100′s Gamma menu, which offers preset choices of gamma curves ranging from 2.0 to 2.4 (in steps of .1). Selecting the 2.4 setting gave us something closer to 2.35 in actuality, although that should be sufficient for most users.
In the interests of total accuracy, we did also try the custom gamma editor. If you read our earlier review of the Panasonic PT-AT6000, where we expressed puzzlement over the strange Colour Management System, well, Epson’s gamma tool seems to be a descendent of this. Upon selecting the custom feature, the user is given the choices of “Adjust it from the image” and “Adjust it from the graph”. The former option presents a bullseye-like cursor over the image, the idea apparently being that the user will hone in on a brightness level they want to play with and adjust from there. As it happens, this is just a front end for the “graph” option. Like Panasonic’s CMS, the Epson gamma editor also freezes the video image rather than keeping it live during adjustments, so adjusting test patterns requires backing out a level and reentering. Strange, but not unusable.
The gamma curve screen presents the user with 9 adjustable points, which are labelled as [Color Tone 1] through [Color Tone 9] (although control is only given over the luminance of the points, not individual R/G/B curves, so the naming is a little strange). Epson would do well to take some lessons from other manufacturers (Panasonic and JVC come to mind) with the design of this, because prior to experimenting, calibrators have no idea of knowing what stimulus level “Color Tone 2″ refers to. Logically you might think it would be 20 IRE (2 x 10 = 20), but that’s not actually the case, and there’s also quite a bit of overlap between the controls. We did achieve a gamma closer to 2.4 with this tool, but think that the design needs a rethink. Simply put, it does not inspire confidence – although we could use the control and spend many hours scrutinising the results to make sure there were no errors introduced, an ISF/THX calibrator who hasn’t familiarised themselves with Epson projectors does not always have that luxury, and upon seeing the strangely designed gamma tool, we imagine many would be play it safe and stick with one of the presets instead. That’s not a great loss though, because the “2.4″ preset option is very close to 2.4.
As we discussed earlier, the “Cinema” mode on the Epson EH-TW9100 features a colour gamut which is much, much wider than the standards that DVD, HDTV, and Blu-ray Disc material are conformed to. In fact, the red primary measured so far out that our calibration software couldn’t even plot it on the chart. The “Natural” mode, by comparison, is far more accurate (in fact, it’s just a little UNDERsaturated, but not visibly).
Not only this, but in the “Natural” mode, the pre-calibrated colour luminance levels are so close to ideal, that we’re not going to waste space publishing the charts, since there’s little difference. That’s not to say that EH-TW9100 users shouldn’t bother with calibration (Greyscale and Gamma were visibly improved), but Epson appear to be on top of colour.
|Pre-calibration CIE chart with reference to HD Rec.709|
|Pre-calibration colour luminance (coloured bars = targets; black bars = measured values)|
Since we’re aiming for perfection here, we should explain why the colour gamut remains slightly undersaturated post calibration. In the “Natural” mode, raising the [Saturation] controls in the colour management menu (which Epson labels “RGBCMY”) do not work in achieving full saturation (they only raise the luminance). It appears that the “Natural” mode has a hard limit which the CMS can’t work around. That’s strange, seeing as we know from the insanely oversaturated “Cinema” mode that most of the components in the EH-TW9100 can fully saturate the HDTV Rec.709 gamut, but isn’t something we can work around. Fortunately, delta errors for all six colours were calculated as being under the visible threshold of 3.
|Post-calibration CIE chart with reference to HD Rec.709|
|Post-calibration colour luminance (coloured bars = targets; black bars = measured values)|
|Post-calibration colour saturation tracking|
There are some user interface issues on the Epson EH-TW9100 that limit the accuracy of the 3D display mode. To start with, there is no equivalent of the “Natural” mode in 3D; the only available modes on the European model we were sent for review are “3D Dynamic” and “3D Cinema”. “3D Cinema” is the better of the two, but inherits the ultra-wide colour gamut of the 2D “Cinema” mode we discussed earlier. This is where access to the “3D THX” feature present on overseas models would have been beneficial – THX’s 3D certification process involves adjusting their branded picture mode to produce accurate colour in 3D, so it’s a missed opportunity for Epson to not include the same feature here.
As a result of the lack of a good 3D picture preset on the European version of the Epson TW9100, we will be sharing HDTVTest settings on our forum, so that European owners can see an improvement in colour accuracy.
Additionally, the adjustments made to Greyscale tracking (in what Epson has named the “RGB” menu) are not saved discretely for each picture mode, meaning that we were unable to fully compensate for the tint of the 3D glasses without compromising 2D performance. Actually, the settings are saved per-input, so if you can dedicate a second player just to 3D (or even just swap cables), it’s possible to calibrate greyscale for 3D individually. That seems excessive to us, and we imagine that, given the scarcity of 3D calibration (and, apparently, consumer interest in 3D), most users will simply tolerate the minor tint imposed by the glasses in 3D mode.
3D Mode Greyscale
|3D Pre-calibration RGB tracking and delta errors (dEs)|
In the out of the box “3D Cinema” mode, with one of the pairs of glasses bundled with our review unit attached to the front of our colorimeter, the EH-TW9100′s greyscale tracking in 3D was largely consistent, but tinted green. The factory [Contrast] control is also set too high, causing a prominent purpley-red cast to appear in highlights.
|3D Post-calibration RGB tracking and dEs in [Natural] mode|
Because the Epson EH-TW9100 does not have discrete Greyscale/White Balance settings for the 2D and 3D display modes, we couldn’t produce perfect tint-free video. However, there is a partial solution in the form of the [Abs. Color Temp] setting in the basic Image menu, which thankfully is saved separately for 3D. This, coupled with the correction to the [Contrast] setting, resulted in greyscale tracking which wasn’t perfect, but was less tinted than the out of the box condition.
3D Mode Colour
The biggest problem in the pre-calibrated state is with colour. Simply put, there is no good “out of the box” 3D picture mode on the THX-less European version of the EH-TW9100. This wide gamut would be great if we had wide gamut content to feed the projector with, but all existing material outside of a digital cinema environment is mastered for playback with the HDTV colour standard in mind. Adding to the problem is the fact that the gren, cyan and yellow colours have sky-high luminance levels.
|3D Pre-calibration CIE chart with reference to HD Rec.709|
|3D Pre-calibration colour luminance (coloured bars = targets; black bars = measured values)|
Naturally, it was time for us to calibrate. We lowered the [Colour Saturation] control (which, in the 3D mode, does affect saturation, rather than just luminance as in the “Natural” 2D mode) to bring the colour of red closer to the standard. We then calibrated the hue, saturation and luminance levels for all colours in the [RGBCMY] menu.
Everything looked great with charts, but we then played some 3D content and saw that, while we had corrected some of the inaccuracies, the entire picture had some severe hue errors. As it happens, the effects of the [RGBCMY] menu are very different when performed using 100% saturation patterns (the behaviour of the CMS is not linear). For that reason, we used Calman 5′s more in-depth representation of various different saturation levels and jumped back and forth, balancing errors out. This resulted in imperfect, but significantly improved colour accuracy in the 3D display mode. The oversaturated green and yellow points had to remain for this reason.
|3D Post-calibration CIE chart with reference to HD Rec.709|
|3D Post-calibration colour luminance (coloured bars = targets; black bars = measured values)|
While the result was imperfect, it was a gigantic improvement on the “baked” wide gamut 3D display mode. While 3D display does result in a dim image (although not in this case), hyper-saturated colours and sky-high relative luminance levels do not result in the perception of a brighter image – they simply make everyone look like they’ve been sun-burned (even with animated content where realism isn’t a priority). If you watch more than a handful of 3D movies a year, 3D calibration brings about a seriously worthwhile improvement, especially with this projector.
Benchmark Test Results
|Panel uniformity||Good, but red tinge in top right|
|Primary chromaticity||Very Good|
|Motion resolution (approx.)||250-300 lines (native), 500 lines (Frame Creation), see notes|
|Digital noise reduction||Defeatable|
|Luma/Chroma bandwidth (2D Blu-ray)||Full Luma, Chroma horizontally blurred|
|1080p/24 capability||No judder in 2D or 3D|
|Input lag||45ms (Fast image processing mode)|
|Full 4:4:4 reproduction (PC)||No|
|Back to: EH-TW9100 Review|