Pixel 2 XL has been the subject of much controversy, with the creation of conflicts over the phone screen even before launch. After the dust is off, the light becomes a kind of refrain: The 2 XL Pixel screen is plagued with problems, including premature burns, angle change, "muted", "black crush", and "black smear" colors. While some of these problems can be attributed to poor display production, others require a more thorough look. In a detailed analysis of Pixel 2 XL screen performance, we will try to cover each depth as much as we can.
Pixel 2 XL is the big stepmother in Google 2017's flagship phone line, carrying a 5.99-inch POLED screen manufactured by LG. The screen looks very sharp thanks to the 2880 × 1440 resolution, the pixel is in the PenTile Diamond Pixel arrangement.
The Diamond Pixel PenTile array provides an intrinsic anti-aliasing subpixel and increases panel length by using fewer blue subpixels, which deteriorate much faster than the red and green sub-pixels. Consequently, the PenTile subpixel setting has a sub-subset of a third less than the conventional RGB subpixel pattern found on most LCDs, but the PenTile subpixel setting exploits the sensitivity of the human visual cortex to green lighting and lighting (compared with chrominance). It maintains a 1: 1 green pixel-to-pixel ratio, giving TUI the same luma resolution as the conventional RGB line display and introduces potential color fring, but at 2 XL Pixel pixel density, no visible edges and the screen looks very sharp to eyes on most scenerios. An important exception is the VR, but the Diamond Pixel form does help reduce the dreaded door-screen effect.
This is not the first time Google has used this display technology in its phones; Google Pixel, Google Pixel XL, Nexus 6P, Nexus 6, and Galaxy Nexus all have OLED panels with PenTile subpixel settings. Furthermore, all mobile OLED displays are capable of removing colors that are outside the sRGB color gamete. Almost all the color of the content is intentionally explained in relation to the sRGB color gamete, so it's important for the display to be able to properly color it. The problem is that these phones initially did not set the color of the content in their original display mode, producing colors with more chrominance than the original content creator in question. Google takes the initiative to address this issue by releasing Pixel 2 and Pixel 2 XL, along with Android Oreo, which introduces color management for devices that support wide color.
With Pixel 2 and Pixel 2 XL, Google says that "[intent] their design is to achieve more natural and accurate color rendition". We will assess the performance of the Pixel 2 XL display, and conclude if its efforts with regard to color accuracy require praise.
Color Difference Metrics
We will use the CIEDE2000 color difference measurement (abbreviated to ΔE), providing luminance compensation, as a metric for chromatic accuracy. Other color difference metrics exist, such as the Δu'v 'color difference in the CIE 1976 u'v' chromaticity diagram, but these metrics are lower than for perceptual uniformity, as the threshold for apparent differences (JND) between colors can vary greatly. For example, the color difference of 0.008 Δu'v 'is not visually visible for blue, but the same color difference for yellow is very striking. CIEDE2000 is an industry standard color difference metric proposed by International Commission on Illumination (CIE) which best describes the uniform perceptual differences between colors. These metrics typically consider the lighting in their calculations because lighting is an important component to describe the overall color, which is helpful when calibrating the screen with certain brightness. But smartphone displays continue to change in brightness, and overall errors can fluctuate when measuring different levels of brightness. For this reason, the lighting error will be compensated for our ΔE value so that only the chromaticity is measured. Display color measurements will be taken with display brightness of 200 cd / m2 to ensure consistency, and the luminance errors presented will conform to the standard gamma power sRGB standard 2.2 for reference.
In general, when the ΔE color difference is below 3.0, the color difference is only seen in diagnostic conditions, such as when the color is measured and the target color appears right next to each other on the measured screen. Otherwise, the color difference is not visually visible and looks accurate. An ΔE of 1.0 or less is said to be utterly indistinguishable from perfect, and appears identical to the target color even when adjacent to it.
Brightness Pixel 2 X
Our 2 XL Pixel Unit achieves a maximum brightness of 474 cd / m2 at the APL level of 100% or the average image level (the percentage of the average active luminance of each subpixel relative to the specified display brightness), which is a respectable improvement of cd 418 Pixel XL / m2 and Pixel 2's 432 cd / m2. Note that this measurement is taken after the Android 8.0 update in November 2017, which Google believes reduces the maximum brightness of Pixel 2 XL by 50 nits (cd / m2). This decrease is only seen in lower APL, where Pixel 2 XL should be brighter. However, this competes with LCD brightness measured from 480 cd / m2 at 100% APL in automatic brightness with the brightness overdrive setting enabled.
The average APL for media consumption hovers around 40%, however, the brightness measurement around the APL range is much more practical. At 50% APL, our 2 XL Pixel measures 530 cd / m2, which is bright enough for outdoor use, but is defeated by the likes of Note 8, which we calculate 643 cd / m2 on APL 50%. Unlike Note 8, Pixel 2 XL does not offer a brightness overdrive feature, and maintains the same maximum brightness with Adaptive Brightness on or off.
The display drops to 4.1 cd / m2 at the lowest brightness level with Adaptive Brightness off. With Adaptive Brightness enabled, the screen will drop to 1.6 cd / m2 - almost the same as most other smartphone displays.
Grayscale Accuracy and Intensity
Accurate grayscale and white point values are essential to produce accurate colors. Shifts in the gray scale will spread errors throughout the entire gamete display (except 100% primates - red, blue, and green), so it's important to analyze the grayscale screen to evaluate the source of the main error when measuring color accuracy. Google states that it calibrates the Pixel 2 XL display to the white dot D67, which is not a good start for accurate color chasing.
The average correlated color temperature is indeed around Google that claimed 6700K. White dots at higher intensities become colder, peaking at 7239K on 95% white skin, which is in the range of most content backgrounds. From this deterioration, we can see that the blue screen shifts on almost any intensity, which will affect the color mix - especially the secondary color. Note also that the grayscale for Natural and Boosted color profiles is exactly the same.
Pixel 2 XL display of gamma display a bit apprehensive. The standard target gamma for sRGB / Rec.709 is a consistent power curve 2.2. However, the gamma display of Pixel 2 XL seems to follow the 2.4 power curve, which is popular in HDTV before BT.1886 recommendations. As a result, the color mix may appear darker on the phone display, and the range of exposure among blacks will increase.
This is not wrong to target - many HDTVs still target this power curve, and the human eye is much more sensitive to darker shades of color than brighter shades of color (though only really visible if the viewer is in a dark environment) - but Google failed to see the consequences of applying this darker power curve to the smartphone. Higher gamma strength is meant for cinema and big TV in dark environments. Smartphones are smaller, clearer, and used in a variety of lighting conditions, so the resulting low intensity colors are not ideal in all environments, such as outside on a sunny day. They will be better served by lower gamma power functions, such as 2.0, which provide better visibility with low intensity colors.
In addition, the high power Pixel 2 XL curve farther shot the blacks close to 0% intensity. The "black outbreak" is a hardware limitation attached to the current generation OLED display, as it has a minimum minimum non-black level that is usually not dim enough to give the full 8 bit depth intensity except at a very high brightness level. For screen calibrators insisting on a 2.4-gamma display, the BT.1886 recommendation partially corrects the black clipping problem by suggesting an initial lower power curve for lower intensity leading to the 2.4 power curve. The lower echoes near the black level will help brighten up some of the initial lighting steps, and the gamma specification is much more suited for OEMs who want to apply cinematic shades on their smartphone displays while minimizing ruined blacks.
In the case of Pixel 2 XL, it appears that Google is using an abnormally early gamma power function - even higher than 2.4 - for lower lighting ranges. It will capture blacks further than usual for OLED displays and will negatively impact the darker film and video display. In the context of full step measurement for a lower 20% exposure range, our Pixel 2 XL intensity scale looks jagged and pulls intermediate steps, as seen by straight horizontal lines and sudden sharp changes for the first 6% of lighting. distance. Anything under 3% will be destroyed.
Note that when it comes to casual media consumption, the lighter shades will be blackened, because the threshold for clipping becomes black increases with APL content. Extremely destructive and exaggerated intensity scale seems to be an incorrect Google result transferring the intensity scale of XL Pixel 2 while calibrating the screen to sRGB.
When the Pixel 2 XL is set to the original display gamete, the intensity scale becomes smoother, and the clipping threshold turns black from 3% to 2.4%, placing Pixel 2 XL in accordance with Note 8 with respect to black. cutouts. Both Pixel 2 XL and Note 8 will benefit much from higher initial gamma to brighten blacks and minimize black clipping.
What is surprising is that the Pixel 2 XL has one of the most accurate grayscatch sequences on any smartphone display in its original view, even beyond our Note 8 unit.
Despite the higher gamma and intentional white spot variations, grayscade Pixel 2 XL still conforms to the sRGB / Rec.709 specification. Grayscale in Natural and Boosted color profiles yields an average color temperature of 6740K and an average grayscade color difference of ΔE = 2.01. In the Saturated color profile, which is the original display of Pixel 2 XL, Pixel 2 XL has a very striking grayscore color difference, close to the perfect average ΔE = 1.22. We wonder how much better if Google provides sRGB color profiles with the grammatical accuracy of the original gamut, or better yet, the color temperature slider like Samsung and others have done. This is a complete improvement in Pixel XL grayscure accuracy, although Pixel XL does have a superior 2.2 gamma power feature. Pixel 2 XL's grayscale in Natural and Boosted color profile is not as accurate as grayscale Note 8 in Basic screen mode, but the precision of grayscale Pixel 2 XL is fine, and without diagnostic reference, is visually accurate.
Saturation and Color Accuracy
Outside the box, the default Pixel 2 XL to Google's Boosted color profile, which targets an expanded sRGB color gamelan of 10% in all directions to a slight increase in color spirits. Google claims to have failed to sign in to this profile because "[h] umans assumes color is not glowing on smaller screens, like on smartphones". While this might be a good idea, Google does not take into account the uneven light sensitivity of the human eye: Reds appear slightly elevated, green and yellow vegetables get a bigger boost that converts the high intensity mixture into sickly, fluorescent and blue blues It seems they are barely have a boost at all.
Before analyzing the default Pixel 2 XL profile, we first see the Natural color profile of the phone, which targets the SRGB color gamete with the white dot D67.
Natural Color Profile PIXEL 2 X
In the CIE 1976 u'v chromaticity chart, Pixel 2 XL covers about 92.3% of the sRGB color gamete, which falls shortest at near-100% intake intensity. However, it is important to note that the CIE chromaticity diagram of 1976 u'v 'is not uniformly perceptive, and the perceptual color difference in red is much worse than the diagram shows; The color difference from 100% red is actually just ΔE 1.34, which is visually undetectable. The blue shift in the gray scale becomes evident in the secondary color, shifting the magenta and cyan toward the blue, and the yellow tilted slightly toward the green. Although the secondary color hue shifts, Pixel 2 XL actually satisfies most of its color, with the average saturation color difference ΔE = 1.78 and the maximum saturation color difference ΔE = 4.22 at 100% cyan.
Do not blame the saturation of luminance. Pixel 2 XL's display touches all its saturated targets with the exception of cyan, the overshoots, but its cinematic display gamma produces colors that may appear dimmer than usual, because gamma is more suitable for low-light viewing. However, as a result of the overall blue shift of Pixel 2 XL on almost all levels of lighting, the red gamma is consistently higher, which means the red color is certainly a bit dim compared to other color mixtures, as seen in the above lighting diagrams chart.
X-Rite ColorChecker, formerly GretagMacbeth ColorChecker, is a set of colors to test the color accuracy of displays. This is in contrast to saturated sweeps by using color blends that often appear in photos and properties, such as skin color and foliage, and which are known to be difficult to reproduce accurately digitally. Display on color accuracy The X-Rite ColorChecker display is helpful in predicting the color performance of screens in photos and movies, while saturated sweeping is more suitable for more solid and vibrant content, such as app icons, logos, colorful wallpapers, animations, and interface elements apps like the Android action bar. Pixel Price 2 XL is excellent in ColorChecker, with X-Rite ColorChecker color difference on average ΔE = 1.85 and color difference X-Rite colorChecker non-grayscale maximum ΔE = 2.41 on cyan color coordinates (0.1473, 0.4120) .
One drawback of OLED-based cavity displays is its white angle dependence, which causes the screen to shift color and brightness at various angles. In our 2 XL Pixel unit, the screen loses a bit of light when tilted at an angle, but experiences a case of angular color that points to blue when viewed perpendicularly.
The color shift in Pixel 2 XL is much worse than Pixel 2, which has an OLED screen manufactured by Samsung. Both phones use different OLED design patterns to cope with angular color shifts, with panel LEDs The XL Pixel 2 Panel is gradually switching to different colors as seen from perpendicular and the Samsung Pixel 2 panels alternate between red and blue, increasing in severity to true- really "rainbow out" near the parallel.
Another disadvantage of OLED displays is that individual diodes take longer to turn on than they do to turn off (the fastest blue subpixels). This results in a ghosting, jelly, or "black smear" effect when low-luminance colors are rotated around a black background. Our 2 XL Pixel unit shows normal ghosting levels, comparable to Note 8.
Display Comparison PiXel 2
When comparing Pixel 2 XL photos and Note 8 displays side by side, they will look very similar at first. However, the temperature difference almost immediately became apparent. In the above comparison, the cold temperature of Pixel 2 XL is very prominent in the blue sky and water; Note 8's warm tones call them back a bit and exaggerate the sun's heat, the highlights on the top left, and the railing at the bottom. No photos are correct - Pixel 2 XL is too cold and Note 8 is too warm. But the less-punchy Note 8 profile makes this photo more accurate.
Moving on to this immaculate portrait selfie, the effect of both display temperature on skin tone is visible. Colder temperatures will make the skin look pale, while warmer temperatures will make the skin look richer in color. The human eye is very sensitive to the color of the skin, and again, the screen does not really photograph correctly - Pixel 2 XL makes the skin look too pale, and Note 8 makes it too warm and saturated for lower skin color intensity. Note 8, however, is more accurate than both.
Pixel 2 XL presents images with great accuracy overall, albeit a little cooler because Google's insistence makes the display feel "fresh". When you share media with friends, it's important to remember that most desktop displays, laptops, and smartphones tend to have a colder white dot, so you can sleep soundly knowing that the gray scale will be more or less the same. Other people viewing your photos in the same color space will see the same thing as you.
While Google has made some questionable decisions in perfecting the Pixel 2 XL display, it is well calibrated and accurate in Natural color profiles - this is more accurate than most HDTVs, computer monitors, and many smartphone displays. Most color errors are not visible in non-diagnostic conditions, and many are completely invisible. And a deliberate tone is something Google can address in future updates for those who prefer a warmer look. However, some Google user interface decisions, along with darker gamma, will make it hard to convince most people that Pixel 2 XL uses the same color profile as Apple's newest iPhone. Unfortunately, the white gradient is applied at the bottom of the original Pixel 2 XL launcher and a small app icon. The Apple iPhone's initial screen looks much more colorful because of its bigger door and shortcut shape (round box has higher fill rate than circle), which uses less white space and sharper color than Android and Google app icons.
The original Pixel 2 XL gamete in Saturated color profiles is accurately calibrated to the DCI-P3 color gametes, so we expect the device to extend the broadest colors properly when more colorful Android apps are managed. (Of course, when using the Saturated color profile to make the lighter shades appear clearer, it does not matter.) There is a large angular change in the blue, more severe on our unit than on the competitor's display. However, many users have displayed photos of their units that do not show any striking color shifts, so that in the end it can get to the quality control issues that Google and LG might be able to tighten up on next-generation OLED displays. The upper side of the LG panel is showing off a bit of light, and that it does not do a rainbow at an extreme angle like Samsung does - as the screen shifts its color, the colors look uniform to parallel, while the Samsung display is not read far from parallel. Minimizing this color shift is of course ideal and improvements can make it superior to Samsung's current color switching solution from the various hues and severity of color shifts.
Our unit also shows small display grains, only visible when observed at a short distance from the screen. It also varies unit-to-unit, so it can be fixed with more stringent quality controls.
Our 2 XL Pixel unit also looks hollow, producing sounds that are heard when the glass is tapped or touched. This is due to excessive air trapped under the glass, which can be caused by poor screen adhesion when OLED screen is laminated to the smartphone chassis. These airbags act as a container for sound and vibration, which causes the audio from the speakers to vibrate the screen with a larger feedback than the screen is fastened. Pixel 2 and most other latest generation smartphones do not have this problem, but most older devices do it. We suspect that design flaws are likely to be oversight - perhaps a result of Google's experience with 3D Gorilla Glass and OLED displays.
This gamma display is arguably the most controversial aspect of the Pixel 2 XL screen, as it makes many of the tones darker than most users. We think the gamma display should be lower or dynamic - higher gamma than Pixel 2 XL makes viewing media in the sun more challenging, although the screen is bright enough. But again, the gamma display, along with the undue transfer of the original display gamete to sRGB (resulting in a black crush), can all be changed in software - depends only on whether Google finds enough reason to do so.