Samsung Galaxy S8 and S8+ Duos Review

Display specifications

Both models are adorned with the so-called Infinity Display, which means this is a dual-edge, almost bezel-less screen. It is the centre point, around which the whole design concept evolves. Samsung even says that they have redesigned the whole device from inside out, in order to come up with this display as an end result. Moreover, as you'll see from our tests below, this screen is not only beautiful but is also the most high-tech smartphone one at the moment. The Super AMOLED panel on both has a WQHD+ resolution - 1440 x 2960 pixels, and an unusual aspect ratio of 18.5:9. The S8 one has a 5.8-inch diagonal size, 570 ppi pixels density and takes up roughly 84.5% of the total front surface. The S8+ display has a 6.2-inch diagonal size, 529 ppi pixel density and takes up 83.6% of the total front surface of the device. In both cases protection is in the "hands" of a Corning Gorilla Glass 5, which covers the back, too. The typical brightness is specified as being 540 cd/m² and the screens cover 90% of the DCI-P3 colour space. Actually, this is partially true because there are four colour gamut modes and each provides different coverage. It is worth mentioning that the devices arrive with a default FHD+ resolution and in case you want to enjoy the screen in its native one, you have to change to WQHD+ from the Settings. Another thing that needs addressing, is that the diagonal sizes measurements are taken if the displays were a full rectangle. If you have to take into account the rounded corners, then the S8 will have a 5.6-inch display and the S8+ will have a 6.1-inch one. In line with the current flagship trends, both models support the HDR10 standard, which is a typical feature of high-end smart TVs. More precisely, the panel holds the Mobile HDR Premium certificate from the UHD Alliance and these are the first smartphones that have it. However, the question about available content remains. Netflix and Amazon services could go on board, but they are not available in every country in the world that sells the S8 and S8+. Plus there's the question of the unusual aspect ratio and resolution. Developers also have a long way to go to provide applications and services that could effectively use that extra real estate on the screen. Both models are provided with extensive Display settings. The main part of them encompasses four display modes called Adaptive display, AMOLED cinema, AMOLED photo, and Basic. The first is the native one, and the other three are specially calibrated to cover a certain colour gamut. There's a night mode with a Blue Light Filter and of course - the Always On Display (AOD), which we will address in the OS and UI section of this review.

Sub-pixel arrangement, viewing angles, APL

The Galaxy S8 and S8+ display panels feature Samsung's Pentile Diamond Pixels sub-pixel arrangement, which has several distinctive features. The blue and the red sub-pixels have a diamond shape and both are quite large, with the blue ones being slightly larger. On the other hand, the green sub-pixels are visibly smaller and oval. Respectively, the number of the blue and red sub-pixels is almost twice as small as the number of the green sub-pixels - 403 sub-pixels per inch for the blue and red against 570 sub-pixels per inch for the green. Viewing angles of both units are perfect. The brightness, contrast and colour shift are minimal and can only be detected by precise measurements. In addition, they are identical in all four display modes for both smartphones. On many occasions in our reviews, we have discussed the specifics of OLED/AMOLED/Super AMOLED displays, which can be summed up in two main groups. The first evolves around the fact that AMOLED displays are capable of displaying infinite black, which is achieved by the individual switching off of pixels and provides higher precision and control over the way content is displayed. In terms of absolute values, this means that the black ones cannot be measured. Since the contrast ratio is the result of the white and black luminance values, it cannot be measured, too. The second group of specifics is in regards to the fact that AMOLED displays are able to transfer more power to each pixel, when they have to display a small white part of the screen, instead of displaying an all-white one. Hence, measuring only one white and black luminance value at a corresponding brightness level will not provide correct information about the brightness and contrast of such displays. In such cases, the APL graph is used. The Average Picture Level (APL) parameter shows the percentage of the white area displayed on the screen compared to a full white display. In our graphs, we use ten APL values, respectively for a white area that takes up 10%, 20%, 30%, etc. till 100% of the display. We have measured the brightness of both the S8 and S8+ displays with a normal ambient light and a high ambient light. The Auto brightness and the default Adaptive display mode are on. The latter provides the highest white luminance (the screen is brighter) compared to the other three modes and is the native wide colour gamut mode of the display. The APL graph showing the screen brightness change in normal ambient light reveals a range of white luminance values from 420 cd/m² to 547 cd/m² for the Galaxy S8 and a range from 400 cd/m² to 585 cd/m² for the Galaxy S8+. Of course, the higher white luminance values correspond to the lower percentage of white displayed on the screens. All these show that in normal light conditions, the displays are bright enough and easily readable. The S8+ is slightly brighter than the S8 one in normal ambient light. The APL graph that depicts the screen brightness change in high ambient light unveils a range of white luminance values from 551 cd/m² to 875 cd/m² for the Galaxy S8 and a range from 555 cd/m² to 986 cd/m² for the Galaxy S8+. A level of almost 1000 nits is truly impressive not only for a smartphone display but for any display out there. Even if you're not interested in the measurements, you will quickly notice that once you go outside and the day is sunny, the display on either of the smartphones, will quickly increase its brightness, while refraining reflections and the content becomes very easily readable.

Galaxy S8 Adaptive display mode

The Adaptive display mode is native for the display and has the widest colour gamut coverage. Samsung even refers to its display as a "Deep Red" OLED one because the colours are quite saturated. This mode is activated by default and provides the highest possible brightness levels in normal and high ambient light conditions and has extensive options for customisation, including an adjustable temperature of the white point, RGB sliders for white colour corrections, and a screen edge colour balance option. The Adaptive mode detects the type of content you have at any given moment on the screen and adapts the display to it. As already mentioned, it has the widest colour space coverage - 142% of the sRGB colour gamut and 113% of the DCI-P3 one. In low light conditions the colours do look more saturated, however, in bright environments, including office spaces, this is actually the preferred mode to use as it compensates the colour wash out due to the reflected light. At normal- to high-levels of ambient light, the Adaptive mode also displays colours more accurately than the other three modes. In normal ambient light conditions the brightness varies from 3 cd/m² to 418 cd/m². In a high-level ambient light, the brightness under this mode can reach 1000 nits. Blacks are infinite and the contrast is great, no doubt about it. The colour temperature is deliberately colder than the golden level of around 6500 K and measures 7500-7600 K, but you can manually adjust it in a range from 6800 K to 8800 K via the slider.

Brightness	White luminance	Black luminance	Contrast	Color temperature
100 %	418.000 cd/m2	0.000 cd/m2	-	7503 K
75 %	255.784 cd/m2	0.000 cd/m2	-	7512 K
50 %	160.285 cd/m2	0.000 cd/m2	-	7692 K
25 %	28.720 cd/m2	0.000 cd/m2	-	7591 K
0 %	3.120 cd/m2	0.000 cd/m2	-	7495 K

Galaxy S8 AMOLED cinema mode

The AMOLED cinema mode covers almost 100% of the DCI-P3 colour space with excellent colour accuracy for this gamut. This coverage is one of the main prerequisites to display HDR content along with a very high brightness of nearly 1000 nits, deep blacks and excellent contrast. This mode has been achieved after deliberate calibration of the display. The CIE diagram of our review unit shows an especially wider coverage of the green and red areas. White luminance values in normal ambient light vary from 3 cd/m² to 407 cd/m². The temperature of the white point is lower (colours are warmer compared to the Adaptive display mode) and is in the 6600-6800 K range, which is nearly perfect.

Brightness	White luminance	Black luminance	Contrast	Color temperature
100 %	406.963 cd/m2	0.000 cd/m2	-	6613 K
75 %	249.784 cd/m2	0.000 cd/m2	-	6611 K
50 %	156.540 cd/m2	0.000 cd/m2	-	6799 K
25 %	27.965 cd/m2	0.000 cd/m2	-	6821 K
0 %	3.031 cd/m2	0.000 cd/m2	-	6785 K

Galaxy S8 AMOLED photo mode

The AMOLED photo mode is deliberately calibrated to provide excellent coverage of the Adobe RGB colour gamut (almost 100%). As its name suggests, it will be perfect for previewing and editing photos and using advanced imaging applications. The white luminance values and the temperature of the white point of our review units are so near in absolute value to those of the AMOLED cinema mode, that they might as well be deemed as a statistical mistake. The white luminance values range is from 3 cd/m² to 407 cd/m² and the color temperature's range is from 6600 K to 6800 K range. However, the CIE diagrams of the cinema and photo modes differ, with the latter one offering a more limited coverage of the red colour area and a slightly decreased, but still wide coverage of the green one. Blue coverage is slightly limited, too. Colour accuracy in the context of the Adobe RGB gamut is excellent.

Brightness	White luminance	Black luminance	Contrast	Color temperature
100 %	405.618 cd/m2	0.000 cd/m2	-	6602 K
75 %	249.601 cd/m2	0.000 cd/m2	-	6600 K
50 %	156.443 cd/m2	0.000 cd/m2	-	6790 K
25 %	27.935 cd/m2	0.000 cd/m2	-	6800 K
0 %	3.023 cd/m2	0.000 cd/m2	-	6752 K

Galaxy S8 Basic mode

The fourth and final display mode is called Basic and is deliberately calibrated to cover the sRGB / Rec.709 colour space, which in terms of everyday use you find on most web content, non-professional photos and videos, computer content, etc. Calibration is almost razor-sharp accurate. The CIE diagram of our review unit shows a limited coverage (slightly less than the sRGB limits) of the green and red. The white luminance values in normal ambient light vary from 3 cd/m² to 402 cd/m². The temperature of the white point remains in the 6600-6800 K range. It is obvious that the cinema, photo and basic modes are calibrated to be accurate at a low-to-normal ambient light.

Brightness	White luminance	Black luminance	Contrast	Color temperature
100 %	401.453 cd/m2	0.000 cd/m2	-	6633 K
75 %	247.097 cd/m2	0.000 cd/m2	-	6629 K
50 %	154.837 cd/m2	0.000 cd/m2	-	6813 K
25 %	27.707 cd/m2	0.000 cd/m2	-	6803 K
0 %	2.997 cd/m2	0.000 cd/m2	-	6775 K

Galaxy S8+ Adaptive display mode

Under the Adaptive display mode, which is the native one for the screen and is switched on by default, our review unit of the Galaxy S8+ shows a white luminance values range from 2.9 cd/m² to 426 cd/m² in normal ambient light conditions. The display of the S8+ is only slightly brighter than the one of the S8 at the 100% and 75% brightness levels and only slightly darker at the 0% and 25% brightness levels. It is also slightly colder with the temperature of the white point varying from 7900 K to 8100 K. Even without measurements, if you put the two devices together, it is obvious that the screen of the S8 in its default settings is warmer than the one of the S8+ in its default settings. The CIE diagram of the S8+ is almost identical to the one of the S8 in the Adaptive display mode.

Brightness	White luminance	Black luminance	Contrast	Color temperature
100 %	426.000 cd/m2	0.000 cd/m2	-	7851 K
75 %	261.784 cd/m2	0.000 cd/m2	-	7995 K
50 %	159.705 cd/m2	0.000 cd/m2	-	8007 K
25 %	25.662 cd/m2	0.000 cd/m2	-	8095 K
0 %	2.890 cd/m2	0.000 cd/m2	-	7925 K

Galaxy S8+ AMOLED cinema

The AMOLED cinema mode of the S8+ provides almost identical coverage of the DCI-P3 colour space as the one of the S8. Under this mode, the display is still slightly brighter and slightly colder at all brightness levels compared to the one of the S8. The white luminance values in normal ambient light vary from 2.8 cd/m² to 414 cd/m². The temperature of the white point varies from 6900 K to 7200 K.

Brightness	White luminance	Black luminance	Contrast	Color temperature
100 %	414.313 cd/m2	0.000 cd/m2	-	6859 K
75 %	253.651 cd/m2	0.000 cd/m2	-	6944 K
50 %	154.483 cd/m2	0.000 cd/m2	-	6971 K
25 %	24.871 cd/m2	0.000 cd/m2	-	7230 K
0 %	2.815 cd/m2	0.000 cd/m2	-	7157 K

Galaxy S8+ AMOLED photo mode

The AMOLED photo mode of the S8+ follows the same calibration pattern as the one of the S8, but the colour space coverage is very slightly smaller in all three colour areas. The difference is so small, it could be deemed as a statistical mistake. The white luminance values range is from 2.8 cd/m² to 410 cd/m² and the color temperature's range is from 6900 K to 7200 K.

Brightness	White luminance	Black luminance	Contrast	Color temperature
100 %	410.67 cd/m2	0.000 cd/m2	-	6876 K
75 %	252.030 cd/m2	0.000 cd/m2	-	6946 K
50 %	154.000 cd/m2	0.000 cd/m2	-	6977 K
25 %	24.875 cd/m2	0.000 cd/m2	-	7257 K
0 %	2.807 cd/m2	0.000 cd/m2	-	7167 K

Galaxy S8+ Basic mode

In a similar fashion to the S8, the Basic mode of the S8+ aims at 100% coverage of the sRGB / Rec.709 colour space, with limited coverage of the green and red areas. Actually, the CIE diagrams of both devices under this mode are almost identical. The white luminance values in normal ambient light vary from 2.8 cd/m² to 410 cd/m². The temperature of the white point remains in the 6900-7200 K range. Again, in the case of the S8+, it is evident that the cinema, photo and basic modes are calibrated to be accurate at a low-to-normal ambient light.

Brightness	White luminance	Black luminance	Contrast	Color temperature
100 %	410.376 cd/m2	0.000 cd/m2	-	6910 K
75 %	252.395 cd/m2	0.000 cd/m2	-	6984 K
50 %	154.683 cd/m2	0.000 cd/m2	-	7011 K
25 %	24.933 cd/m2	0.000 cd/m2	-	7279 K
0 %	2.823 cd/m2	0.000 cd/m2	-	7212 K