Galaxy S8 OLED Display Technology Shoot-Out

Dr. Raymond M. Soneira

President, DisplayMate Technologies Corporation

Copyright © 1990-2017 by DisplayMate Technologies Corporation. All Rights Reserved.

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Galaxy S7 Galaxy S8 Galaxy S7 Edge

Introduction

The key element for a great Smartphone has always been a truly innovative and top performing display, and the best leading edge Smartphones have always flaunted their super high tech displays. It is the display performance that determines how good and how beautiful everything on the Smartphone looks, including the camera photos and all of your Apps, and also how readable and how usable the screen is in high ambient lighting. The Display is the crown jewel of the Smartphone!

The Galaxy S8 and Galaxy S8+ are Samsung’s latest flagship Smartphones with their newest most advanced state-of-the-art Flexible OLED Displays together with a radical new Full Display Screen design that fills almost the entire front face of the phone, providing a significantly larger display for the same size phone. With mobile OLED display technology now advancing faster than ever, they have many important new display performance enhancements. The displays on the Galaxy S8 and the larger Galaxy S8+ not only have major improvements in their OLED display hardware, but they also have many new and enhanced display features and display functions that we will also cover in detail.

Both models have the latest dual-edge curved screen Flexible OLED Displays that set a number of new display performance records. While the OLED display itself is flexible, the screen remains rigid under an outer hard cover glass that is hot formed into a rigid curved screen. The curved screen provides two additional user configurable Edge Screen areas that can be viewed from both the front or the sides, and even when the phone is placed face down. With the Always On Display mode the Edge Screen can even be used as a Night Clock for your bedside table.

In this article we lab test, measure, analyze, and evaluate in depth the display on the Galaxy S8. This is an independent scientific objective lab test and analysis of OLED displays written for consumers and journalists. It is the latest edition in our seven year article series that has lab tested, tracked and analyzed the development of mobile OLED displays and display technology, from its early beginnings in 2010, when OLED displays started out in last place, into a rapidly improving and evolving display technology that now has a commanding first place lead and continues pushing ahead aggressively.

The Galaxy S8 is the first in a new generation of OLED Smartphones that have a Full Screen Display design. It is the most innovative and high performance Smartphone display that we have ever lab tested, earning DisplayMate’s highest ever A+ grade.

Some Galaxy S8 Display Highlights

These are just some of the Galaxy S8 Display Highlights that we will be covering in detail throughout the article:

· A new 3K Higher Resolution 2960 x 1440 display that fills almost the entire front face of the phone from edge-to-edge, resulting in a larger 5.8 inch display with a taller height to width Aspect Ratio of 18.5 : 9 = 2.05.

· A new and accurate full 100% DCI-P3 Color Gamut that is also used for 4K TVs. Plus it is the first Smartphone to be certified by the UHD Alliance for Mobile HDR Premium, which allows it to play all of the latest content produced for 4K UHD Premium TVs.

· The Native Color Gamut of the Galaxy S8 is even larger, the result of its new high saturation “Deep Red” OLED, resulting in a very impressive 113% of DCI-P3 and 142% of sRGB / Rec.709 Gamuts that also produces better on-screen Colors in High Ambient Light.

· The Galaxy S8 has 5% to 19% Higher Screen Brightness, plus a record Peak Brightness of over 1,000 nits.

The full set of Galaxy S8 Display Highlights are listed below under What’s New and What’s Improved.

Comparing the Galaxy S8 and Galaxy S7 Displays

The Galaxy S8 has a 5.8 inch (5.2” x 2.5”) curved screen OLED display. The larger Galaxy S8+ has a 6.2 inch (5.6” x 2.7”) curved screen OLED display with the same display performance specs and the same 3K 2960x1440 resolution as the smaller Galaxy S8.

For comparison, the 2016 Galaxy S7 has a 5.1 inch (4.4” x 2.5”) flat screen OLED display, and the Galaxy S7 Edge has a 5.5 inch (4.8” x 2.7”) curved screen display. The entire Galaxy S8 phone is 0.25 inches taller than the entire Galaxy S7 phone, and 0.1 inches shorter than the entire Galaxy S7 Edge phone. In 2016 we lab tested both Galaxy S7 models, which have the same display performance and the same 2.5K 2560x1440 resolution. For detailed test results see our article on the Galaxy S7 Display Technology Shoot-Out. In this article we will regularly compare the Galaxy S8 to the Galaxy S7 display.

Article Overview

This article has the following major sections:

· What’s New

· What’s Improved

· Highlights and Performance Results

· Galaxy S8 Conclusions

· The Future of OLED Smartphones

· Improving the Next Generation of Mobile Displays

· Lab Measurements and Comparison Table

What’s New

The Galaxy S8 has the following major new display performance features and display functions, which we cover in detail throughout the article:

· A new larger 5.8 inch Full Screen Display that fills almost the entire front face of the Galaxy S8 from edge-to-edge. Its display is 18% larger in screen area than the Galaxy S7, with almost exactly the same width but 17% taller. The Home button and Navigations buttons are now incorporated within the touchscreen display.

· A new display form factor with a taller height to width Aspect Ratio of 18.5 : 9 = 2.05, which is larger than the 16 : 9 = 1.78 on the Galaxy S7 (and widescreen TVs) because the display now has the same overall shape as the entire phone. It is taller in Portrait mode and wider in Landscape mode. This provides extra space for Notifications and for displaying multiple windows and content.

· A new 3K Higher Resolution 2960 x 1440 Quad HD+ display with 570 pixels per inch.

· Support for 4 Screen Modes and 3 Standard Color Gamuts with High Absolute Color Accuracy based on our extensive lab measurements.

· A new full 100% DCI-P3 Color Gamut and Digital Cinema mode that is also used for 4K Ultra HD TVs, so the Galaxy S8 can display the latest high-end 4K video content. The DCI-P3 Gamut is 26 percent larger than the Rec.709 Gamut that is used in 2K Full HD TVs.

· The Galaxy S8 is the first Smartphone to be certified by the UHD Alliance for Mobile HDR Premium, which allows it to play all of the same 4K High Dynamic Range content produced for 4K UHD Premium TVs.

· A new Video Enhancer that provides HDR-like Expanded Dynamic Range for photos and videos that don’t have HDR coding.

· A new record high Peak Brightness with over 1,000 nits, which improves screen visibility in very high Ambient Light, and provides the high screen Brightness needed for HDR.

· A new user adjustable White Point with RGB Color Balance slider controls that can change the Color of White for the Adaptive Display screen mode.

· New front and back Dual Ambient Light Sensors for significantly improved Automatic Brightness settings.

· A new Night Mode with a Blue Light Filter that allows the user to adjust and reduce the amount of blue light from the display for better night viewing and improved sleep.

What’s Improved

The Galaxy S8 also has the following improved display performance features and display functions, which we cover in detail throughout the article:

· Higher Screen Brightness from 5% to 19%.

· Larger Native Color Gamut with 113% DCI-P3 for better displayed Colors in High Ambient Light.

· Improved Absolute Color Accuracy.

· Improved Viewing Angle performance.

· Enhanced configurable Edge Display for the curved side screens.

· Enhanced Always On Display mode operated with IC hardware rather than App software.

· Enhanced Personalized Auto Brightness Control.

· Enhanced Image Processor for Adaptive Dynamic Brightness and Contrast Range Expansion.

· Enhanced Performance Modes and Power Saving Modes.

· Stronger curved Gorilla Glass 5 protecting the display.

We’ll cover all of the these display performance topics and much more, with in-depth comprehensive display tests, measurements and analysis that you will find nowhere else.

The Display Shoot-Out

To examine the performance of the new Galaxy S8 OLED Display we ran our in-depth series of Mobile Display Technology Shoot-Out Lab tests and measurements in order to determine how the latest OLED displays have improved. We take display quality very seriously and provide in-depth objective analysis based on detailed laboratory tests and measurements and extensive viewing tests with both test patterns, test images and test photos. To see how far OLED and LCD mobile displays have progressed in just six years see our 2010 Smartphone Display Shoot-Out, and for a real history lesson see our original 2006 Smartphone Display Shoot-Out.

Samsung provided DisplayMate Technologies with pre-release production units of the Galaxy S8 so that we could perform our well known objective and comprehensive DisplayMate Lab tests, measurements, and analysis, explaining in-depth the new display performance results for consumers, reviewers, and journalists as early as possible.

Highlights and Performance Results

In this section we review and explain the principal results from the extensive DisplayMate Lab Tests and Measurements covered in the Display Shoot-Out Comparison Table under the following categories: Display Specifications, Overall Assessments, Screen Reflections, Brightness and Contrast, Colors and Intensities, Viewing Angles, OLED Spectra, Display Power.

Main Topics Covered

This Highlights and Performance Results section has detailed information and analysis on the Galaxy S8 display for the main topics listed below. You can skip this section and go directly to the Galaxy S8 Conclusions.

· Larger Full Screen Display

· 3K Higher Resolution Display

· Multiple Screen Modes

· High Absolute Color Accuracy

· Adaptive Display Screen Mode with User Adjustable White Point

· Adaptive Display Screen Mode in Ambient Light

· Screen Brightness and Higher Automatic Brightness

· High Dynamic Range Mobile HDR Premium Display

· Front and Back Dual Ambient Light Sensors

· Interactive Personalized Automatic Brightness

· Night Mode Blue Light Filter for Better Night Viewing

· Always On Display Mode

· Diamond Pixels

· Display Power Efficiency

· Viewing Angle Performance and Viewing Tests

· Display Related Enhancements

New Larger Full Screen Display with a New Aspect Ratio of 18.5 : 9

The Galaxy S8 has a new larger 5.8 inch full screen display that fills almost the entire front face of the Galaxy S8 from edge-to-edge. Its display is 18% larger in screen area than the Galaxy S7, with almost exactly the same width but 17% taller. The Home button and Navigations buttons are now incorporated within the touchscreen display.

The display also has a new form factor with a taller height to width Aspect Ratio of 18.5 : 9 = 2.05, which is larger than the 16 : 9 = 1.78 on the Galaxy S7 (and widescreen TVs) because the display now has the same overall shape as the entire phone. It is taller in Portrait mode and wider in Landscape mode. This provides extra space for Notifications and for displaying multiple windows and content.

The main screen has rounded corners and is curved along both the left and right edges, which provides two additional user configurable Edge Screen areas that can be viewed from both the front or the sides, and even when the phone is placed face down. This is particularly helpful for status messages, notifications, memos, an Edge Clock, and a Night Clock in the Always On Display mode, which we cover below.

New 3K Higher Resolution Quad HD+ 2960x1440 Display with 570 pixels per inch

As a result of its larger display size and larger Aspect Ratio, the Galaxy S8 has a new 3K Higher Resolution Quad HD+ display with 2960x1440 pixels and 570 pixels per inch, with 4.3 Mega Pixels, more than double the number on your HDTV. It can display more than four complete HD 1280x720 images at once. The display has Diamond Pixels (see below) and Sub-Pixel Rendering with 570 pixels per inch (ppi), providing significantly higher image sharpness than can be resolved with normal 20/20 Vision at the typical viewing distances of 10 inches or more for Smartphones, so the display appears perfectly sharp.

The Galaxy S8 uses Sub-Pixel Rendering, which further improves image sharpness because the individual Red, Green and Blue Sub-Pixels are treated as independent addressable image elements and are not bound together into fixed Pixels, so the closest sub-pixel is used when rendering the image. In some cases Sub-Pixel Rendering can make the screen appear to have up to 3 times the resolution of traditional Pixel Rendering. As a result, for Smartphones it is absolutely pointless to further increase the display resolution and pixels per inch (ppi) up to 4K (3940x2160 pixels) for a silly marketing wild goose chase into the stratosphere…

· Multiple Screen Modes and Color Management

One very important capability of the Galaxy Smartphones that is often overlooked by many consumers and reviewers, is the set of user selectable Screen Modes that are available under Display Settings, which we cover and measure each one in detail below. Most Smartphones and Tablets only provide a single fixed factory display Color Gamut and color calibration, with no way for the user to alter it based on content, personal preferences, running applications, or Ambient Light levels. A very important capability provided by the OLED Galaxy Smartphones is the implementation of Color Management that provides a number of user selectable Screen Modes, each with different Color Gamuts and levels of Color Saturation and display calibration based on user and application preferences. Color Management with multiple and varying Color Gamuts are a very useful and important state-of-the-art capability that all manufacturers will need to provide in the future.

· High Absolute Color Accuracy for Each of the Screen Modes

All of the recent Galaxy OLED Smartphones have supported multiple Color Gamut Standards, including DCI-P3, Adobe RGB, and sRGB / Rec.709. For each of the Screen Modes we carefully measure the Absolute Color Accuracy using an advanced series of spectroradiometer measurements with 41 Reference Colors that provide a detailed map of the Color Accuracy throughout the entire Color Gamut for each Screen Mode. Absolute Color Accuracy is measured in terms of J ust N oticeable C olor D ifferences, JNCD. See this Figure for an explanation and visual definition of JNCD and the detailed Color Accuracy Plots showing the measured Color Errors for the 41 Reference Colors for each Color Gamut.

In order to see the high Color Accuracy, the Display Setting for the Screen Mode needs to match the Color Gamut for the content that is being viewed. All of the reviewers that continue to rant about the poor Color Accuracy of the Galaxy OLED displays have failed to set the proper Screen Mode for their content, which is very accurate as shown in our extensive Lab Measurements and Viewing Tests.

For all of the calibrated Screen Modes, the Galaxy S8 has uniformly Very Good to Excellent Absolute Color Accuracy, which are covered and measured individually below. See our detailed Absolute Color Accuracy Plots with 41 Reference Colors for the 3 calibrated Screen Modes and also this regarding Bogus Color Accuracy Measurements.

New Four Selectable Screen Modes and Color Gamuts

The Galaxy S8 has four user selectable Screen Modes: Adaptive Display, AMOLED Cinema, AMOLED Photo, and the Basic Screen Mode, which matches the Standard sRGB / Rec.709 Color Gamut that is used for producing most current consumer content. See this Figure for the Color Gamuts of all the tested Screen Modes and the Colors and Intensities section for the measurements and details. Note that the Adaptive Display screen mode is the standard and factory default Screen Mode. Use Display Settings to switch between the other available Screen Modes. We discuss each of the four tested Screen Modes next…

New AMOLED Cinema Screen Mode with a Very Accurate Standard DCI-P3 Color Gamut

The Galaxy S8 has the newest Standard Wide Color Gamut called DCI-P3 for D igital C inema I nitiative, which is being used for 4K Ultra HD TVs and in Digital Cinema for the movie industry. So the Galaxy S8 can display the latest high-end 4K video content. The DCI-P3 Gamut is 26 percent larger than the Rec.709 Gamut used in 2K Full HD TVs, both are compared in this accurately colorized Figure. The larger DCI-P3 Color Gamut and wider range of more saturated colors are also useful in many advanced imaging applications, including HDR High Dynamic Range (below). The Galaxy S7 does not have the DCI-P3 Color Gamut.

The measured Color Gamut of the AMOLED Cinema screen mode is a close to perfect full 100 percent of the Standard DCI-P3 Color Gamut, and the measured Absolute Color Accuracy is a very accurate 2.7 JNCD, which is very likely considerably better than your living room 4K Ultra HD TV. The Galaxy S8 is one of the first displays to reach full 100% of the DCI-P3 as the result of using a new high saturation “Deep Red” OLED. See the Color Accuracy section and the detailed Color Accuracy Plots for the measurements and details. Select the AMOLED Cinema screen mode using Display Settings – it is not the default screen mode for the Galaxy S8.

· AMOLED Photo Screen Mode with a Very Accurate Standard Adobe RGB Color Gamut

Most high-end digital cameras have an option to use the Adobe RGB Color Gamut, which is 17 percent larger than the Standard sRGB / Rec.709 Color Gamut used in consumer cameras. The AMOLED Photo screen mode on the Galaxy S8 provides a very accurate Color and White Point calibration to the Adobe RGB standard, which is rarely available in consumers displays, and is very useful for high-end digital photography and other advanced imaging applications.

The measured Color Gamut of the AMOLED Photo screen mode is a very accurate 98 percent of the Standard Adobe RGB Color Gamut, and the measured Absolute Color Accuracy is a very accurate 2.7 JNCD. See the Color Accuracy section and the detailed Color Accuracy Plots for the measurements and details. Select the AMOLED Photo screen mode using Display Settings – it is not the default screen mode for the Galaxy S8.

· Basic Screen Mode with a Very Accurate Standard sRGB / Rec.709 Color Gamut

The Basic screen mode provides a very accurate Color and White Point calibration for the Standard sRGB / Rec.709 Color Gamut that is used to produce most current consumer content for digital cameras, TVs, the internet, and computers, including photos, videos, and movies. The measured Color Gamut of the Basic screen mode is a very accurate 101 percent of the Standard sRGB / Rec.709 Color Gamut, and the measured Absolute Color Accuracy is a very accurate 2.3 JNCD, which is very likely considerably better than your living room HDTV and also your laptop and computer monitor.

Use the Basic screen mode for the best color and image accuracy for most current consumer content, which is especially important when viewing photos from family and friends (because you often know exactly what they actually should look like), for some TV shows, movies, and sporting events with image content and colors that you are familiar with, and also for viewing online merchandise, so you have a very good idea of exactly what colors you are buying and are less likely to return them. See the Color Accuracy section and the detailed Color Accuracy Plots for the measurements and details. Select the Basic screen mode using Display Settings – it is not the default screen mode for the Galaxy S8.

· Adaptive Display Screen Mode with the Largest Color Gamut

The Adaptive Display screen mode provides real-time Adaptive processing that can dynamically adjust images and videos. For some applications it will vary the White Point, Color Gamut, and Color Saturation based on the image content and the color of the surrounding ambient lighting measured by the Ambient Light Sensor (which measures color in addition to brightness).

The Adaptive Display screen mode also provides significantly higher Color Saturation, with a large 142 percent of the Standard sRGB / Rec.709 Color Gamut and 113 percent of the Standard DCI-P3 Color Gamut, the highest that we have ever measured for Smartphones and Tablets, and the result of a new high saturation “Deep Red” OLED in the Galaxy S8. Some people like the more saturated and Vivid Colors, plus it is useful for special applications, and especially when using the Galaxy S8 in medium to high levels of Ambient Light, because it offsets some of the reflected light glare that washes out the on-screen image colors. We examine the change in the Color Gamut with Ambient Light below. See the Color Accuracy section for the measurements and details. Select the Adaptive Display screen mode using Display Settings – it is the factory default screen mode for the Galaxy S8.

New Adaptive Display Screen Mode with a User Adjustable White Point

The default White Point for the Adaptive Display screen mode has an intentionally bluish 7,565 K Color Temperature. A new feature on the Galaxy S8 is a user adjustable White Point with RGB Color Balance slider controls that allow users to change color of White for the Adaptive Display screen mode. The slider controls allow the White Point Color Temperature to range from 6,800 K, which is close to the Standard D65 White, up to 8,800 K, which has a strong bluish tint that some people like. So with the Galaxy S8 you can set the Color of White that you prefer.

· Adaptive Display Screen Mode Offsets the Loss of Color Saturation and Color Gamut in Ambient Light

The Adaptive Display screen mode is particularly useful in moderate to high levels of Ambient Light because its larger Native Color Gamut offsets some of the loss of Color Saturation and Color Gamut that occurs when using the other calibrated Standard Screen Modes. This Figure shows the measured decrease in two Color Gamuts with increasing Ambient Light, from 0 lux, which is perfectly dark, up through 2,000 lux, which corresponds to typical outdoor daylight in shade.

At 500 lux, which corresponds to typical office lighting, the measured on-screen Color Gamut for the Basic screen mode falls to 86%. At 1,000 lux, which corresponds to very bright indoor lighting or outdoor daylight with an overcast sky, the measured on-screen Color Gamut falls to 75%, and at 2,000 lux the measured on-screen Color Gamut falls to 58%. This loss of color saturation and wash out in Ambient Light is well known to all display users.

The way to improve the display color accuracy and performance in Ambient Light is to start with a larger Color Gamut, like the Adaptive Display screen mode, which is shown on the right in this Figure compared to the Basic screen mode on the left. At 1,000 lux the Adaptive Display screen mode provides a much better match to the sRGB / Rec.709 Color Gamut than the Basic screen mode. The Adaptive Display screen mode also provides a good match to the DCI-P3 Color Gamut at 500 lux. So the Adaptive Display screen mode provides more accurate on-screen colors in moderate to high Ambient Lighting than the other calibrated Screen Modes, which are designed and calibrated for Low Ambient Light. Applying Dynamic Color Management based on the current Ambient Light lux level in the future will able to further improve color accuracy over a wide range of Ambient Light levels, which we discuss further in the Conclusion.

· Screen Brightness and Performance in High Ambient Lighting

Mobile displays are often used under relatively bright ambient lighting, which washes out the image color saturation and contrast, reducing picture quality and making it harder to view or read the screen. To be usable in high ambient light a display needs a dual combination of high Screen Brightness and low Screen Reflectance – the Galaxy S8 has both. This is extremely important for screen readability, picture quality, and color accuracy in ambient light.

The Galaxy S8 is 5 to 10 percent Brighter than the Galaxy S7, and up to 19% Brighter in High Ambient Light with Automatic Brightness. For most image content the Galaxy S8 provides over 460 cd/m2 (Luminance, which is a measure of Brightness sometimes called nits), comparable or higher than most LCD displays in this size class. The measured Brightness on the Home screen is even higher at over 525 nits. When the display Brightness is set Manually with the slider, it can be adjusted to reach a maximum screen Brightness of up to 610 nits, which is impressive. See the Screen Brightness section for the measurements and details.

The measured Galaxy S8 Screen Reflectance is 4.5 percent, slightly better than the Galaxy S7 and close to the lowest that we have ever measured for a Smartphone. Our Contrast Rating for High Ambient Light quantitatively measures screen visibility and image contrast under bright Ambient Lighting – the higher the better. As a result of its high Brightness and low Reflectance, the Galaxy S8 has a Contrast Rating for High Ambient Light that ranges from 90 to 136, the highest that we have ever measured for a Smartphone. See the Screen Reflectance section for the measurements and details.

· Even Higher Automatic Peak Brightness

On the Galaxy S8 the Maximum Screen Brightness can go much higher when Automatic Brightness is turned On, so that users can’t permanently park the Manual Brightness slider to very high values, which would run down the battery quickly. High Screen Brightness is only needed for High Ambient Light, so turning Automatic Brightness On will provide better high ambient light screen visibility and also longer battery running time.

When Automatic Brightness is turned On, the Galaxy S8 produces up to a very impressive 1,020 cd/m2 (nits) in High Ambient Light, where high Brightness is really needed – which is the brightest Smartphone display that we have ever measured, tied with the Galaxy Note7 and 19% Brighter than the Galaxy S7. As a result of its very high Automatic Brightness and low Reflectance, the Galaxy S8 has a Contrast Rating for High Ambient Light that ranges from 128 to 227, also the highest that we have ever measured for a Smartphone display. See the Brightness and Contrast, the High Ambient Light and the Screen Reflections sections for the measurements and details. The much higher Peak Brightness of over 1,000 nits is also used to provide High Dynamic Range HDR, which we discuss next...

New HDR High Dynamic Range Mobile HDR Premium Display

The Galaxy S8 is the first Smartphone to be certified by the UHD Alliance for Mobile HDR Premium, which allows the Galaxy S8 to play the same 4K High Dynamic Range content for 4K UHD Premium TVs. H igh D ynamic R ange (HDR) is the newest performance enhancement feature developed for the latest 4K Ultra HD TVs. HDR provides expanded the Color, Contrast, and Brightness of video content. In order to provide HDR, the Galaxy S8 has the required Digital Cinema DCI-P3 Wide Color Gamut, plus perfect Blacks and an Infinite Contrast Ratio from its OLED display, and a peak Brightness of over 1,000 nits that is needed for High Dynamic Range. The Galaxy S8 can play the latest streamed mobile HDR videos, and its built-in video processor also allows it to provide an Expanded Dynamic Range for standard video content that produces an HDR-like effect.

New Front and Back Dual Ambient Light Sensors for Improved Automatic Brightness Settings

Other Smartphones and Tablets have just a single Ambient Light Sensor on the front of the screen that measures the amount of light falling on the front of the screen. When Automatic Brightness is turned On, the display Brightness is adjusted based on this single measured value. But that is only part of the story because the phone is often in the shadow of your head, so the front ambient light level is often reduced there. However, your eyes are generally more adapted to the surrounding ambient light level that is behind and around the phone, which needs to be taken into account in setting the proper screen Brightness, particularly with the most common back lighting situations that exist when holding the phone.

I proposed dual Ambient Light Sensors back in 2010, with an article that described “How Automatic Brightness Should Work.” The Galaxy S8 is the first Smartphone (along with the Galaxy Note7) to have a second Ambient Light Sensor on the back that also measures the surrounding ambient light behind the phone and then uses both measured values to adjust the display Brightness based on the front and back lighting. The Galaxy S8 Automatic Brightness Control has also been enhanced to provide improved response and transition times with changing ambient light levels to give your eyes the proper amount of time to adjust to the new levels.

· Interactive Personalized Automatic Brightness Control that Works Well

The Galaxy S8 has a Interactive Personalized Automatic Brightness Control that learns and stores the display brightness settings that you make for varying ambient light levels, so from then on you get your own customized personal visual brightness preferences instead of some pre-programmed manufacturer settings found in other Smartphones, Tablets, and TVs. I proposed this back in 2010, with an article that described “How Automatic Brightness Should Work.” The Galaxy S8 and Galaxy S7 are the first Smartphones, Tablets, or TVs to do Automatic Brightness correctly.

When Automatic Brightness is turned On (under Display Settings), if you adjust the Brightness Slider, the Galaxy S8 will remember your setting along with the current Ambient Light level that is measured by its Ambient Light Sensors (ALS). From then on the Galaxy S8 will automatically adjust the screen Brightness by measuring the current ambient light level and then adjusting the display Brightness based on the settings that you have previously made, so you’ll get a customized screen Brightness setting that you’ve previously trained it to produce for the current level of ambient light – and you can continue to tweak and adjust it as needed. Other smartphones operate using the antiquated opposite approach that works backwards and poorly, which often results in users disabling Automatic Brightness.

New Night Mode Blue Light Filter for Better Night Viewing

The Night Mode Blue Light Filter on the Galaxy S8 is designed to change the color balance of the display in order to reduce the amount of Blue light produced by the display, which some recent research indicates can affect how well users sleep afterwards. In a separate article we explain and analyze the Blue Light issue for displays. The Galaxy S8 includes a user adjustable slider (called Filter Opacity) to vary the amount of Blue light produced by the display and a timer that allows the Blue Light Filter to be turned on and off automatically every day. The measured variation in the display light spectrum with the adjustable Blue Light Filter is shown in this Figure and below.

As the Blue Light Filter Opacity setting is increased, the amount of Blue light emitted by the display decreases. When that happens, White and all screen colors take on an increasing yellowish tint and color cast. At the Middle setting the measured White Color Temperature decreases to 4,500K, and at the Maximum setting it decreases to 2,500K, the Color Temperature of traditional incandescent lighting, which is yellowish. With the Blue Light Filter turned On and the Opacity at its Maximum setting, the measured Blue Light component from the Galaxy S8 is reduced by 80 percent. Turning down the screen Brightness will further decrease the amount of Blue Light. The measured display spectra for several of the Blue Light Filter settings are included in this Figure and below.

Display Spectra Click to Enlarge

· Super Dimming Mode

The Galaxy S8 also has a Super Dimming Mode that allows the Maximum Screen Brightness to be set all the way down to just 2 cd/m2 (nits) using the Brightness Slider. This is perfect for night use on a beside table, and useful for working comfortably without eye strain or bothering others in very dark environments, or affecting the eye’s dark adaptation, such as when using a telescope. The display still provides full 24-bit color and the picture quality remains excellent.

· Always On Display Mode

The Galaxy S8 has an Always On Display mode that takes advantage of the very low power capability of an OLED display when most of the image pixels are black, because every sub-pixel is independently powered, and therefore doesn’t use any power when black. The AOD mode is super power efficient and typically requires only 3 to 5 percent of the maximum display power. So when the phone is off (in standby) it is possible to always display some text and graphics on a black background all day and all night without a significant power drain that would reduce the battery running time. The Always On Display mode uses only 50 to 100 mW (milli-Watts) in normal daytime ambient light, and much less in the dark mode at night. For moving AOD content, such as in an Analog Clock with a second hand, the display is updated via Integrated Circuit hardware rather than App software, resulting in lower power consumption.

The Always On Display produces an illuminated main screen image 24 hours a day so you can always discreetly check it with just a glance. It shows various personalized clock and calendar screens, plus status messages, memos, notifications, and images on the main screen when the phone is off (in standby). It measures the ambient light level and has both day and night modes, and it will stay off when the phone display is face down, or if it senses a dark confined space like a pocket or handbag. The day mode has a measured Luminance of 50 cd/m2 (nits) on a black background, which is very readable but not distracting for normal indoor ambient lighting, and is visible outdoors if you shade the screen with your hand. The night mode is entered for very low Ambient Light lux levels and runs like the Super Dimming Mode down to as low as 1 nit, so it makes a great Night Clock that won’t disturb you if it’s on your bedside table.

· Diamond Pixels

A high resolution screen shot (provided by Samsung) shows an interesting design and sub-pixel arrangement for the Galaxy S8, which Samsung calls Diamond Pixels. First of all, the Red, Green, and Blue sub-pixels have very different sizes – Blue is by far the largest because it has the lowest light emission efficiency, and Green is by far the smallest because it has the highest efficiency. The alternating Red and Blue sub-pixel arrangement leads to a 45 degree diagonal symmetry in the sub-pixel layout. This allows vertical, horizontal, and particularly diagonal line segments and vectors to be drawn with reduced aliasing and artifacts. In order to maximize the sub-pixel packing and achieve the highest possible pixels per inch (ppi), that leads to diamond rather than square or stripe shaped Red and Blue sub-pixels. But not for the Green sub-pixels, which are oval shaped because they are squeezed between two much larger and different sized Red and Blue sub-pixels. It’s a form of high-tech display art…

· Display Power Efficiency

Since 2013 the Display Power Efficiency of the Galaxy series of Smartphones has improved by a very impressive 56%. This year the new OLED materials on the Galaxy S8 have improved optical and power efficiency with its larger Native Color Gamut than on the Galaxy S7 (142% compared to 131% for sRGB / Rec.709).

While LCDs remain more power efficient for images with mostly full screen white content (like all text screens on a white background, for example), OLEDs are more power efficient for typical mixed image content because they are emissive displays so their power varies with the Average Picture Level (average Brightness) of the image content over the entire screen. For OLEDs, Black pixels and sub-pixels don’t use any power so screens with Black or dark backgrounds are very power efficient for OLEDs. For LCDs the display power is fixed and independent of image content. Currently, OLED displays are more power efficient than LCDs for Average Pictures Levels of 65 percent or less, and LCDs are more power efficient for Average Picture Levels above 65 percent. Since both technologies are continuing to improve their power efficiencies, the crossover will continue to change with time.

The Galaxy S8 also has 4 user adjustable Performance Modes and 3 adjustable Power Saving Modes that reduce the Display Power by lowering the screen Brightness and setting the background to Black, which can significantly reduce display power and more than double the running time on battery. All of our tests and measurements were performed in the High Performance Mode with the Power Saving Mode Off. See the Display Power section for the measurements and details.

· Viewing Angle Performance

While Smartphones are primarily single viewer devices, the variation in display performance with viewing angle is still very important because single viewers frequently hold the display at a variety of viewing angles. The angle is often up to 30 degrees, more if it is resting on a table or desk. While LCDs typically experience a 55 percent or greater decrease in Brightness at a 30 degree Viewing Angle, the OLED Galaxy S8 display shows a much smaller 29 percent decrease in Brightness at 30 degrees. This also applies to multiple side-by-side viewers as well, and is a significant advantage of OLED displays. The Color Shifts with Viewing Angle are also relatively small and somewhat better than the Galaxy S7. See the Viewing Angles section for the measurements and details.

· Viewing Tests

The three calibrated Standard Screen Modes on the Galaxy S8 provide very nice, pleasing and very accurate colors and picture quality. Although the Image Contrast is slightly too high (due to a slightly too steep Intensity Scale), the very challenging set of DisplayMate Test and Calibration Photos that we use to evaluate picture quality looked absolutely stunning and Beautiful, even to my experienced hyper-critical eyes.

In order to see the high Color Accuracy, the Display Setting for the Screen Mode needs to match the Color Gamut for the content that is being viewed. All of the reviewers that continue to rant about the poor Color Accuracy of the Galaxy OLED displays have failed to set the proper Screen Mode for their content, which is very accurate as shown in our extensive Lab Measurements.

For indoor and low ambient light viewing use the Basic screen mode for most standard consumer content including digital camera, TV, internet, and computer content, including photos, videos, and movies, and also for your online purchases in order to see accurate product colors. Use the AMOLED Cinema screen mode for viewing the newest DCI 4K Ultra HD TV and Digital Cinema content and videos, including HDR Premium content, and the AMOLED Photo screen mode to view high-end digital camera photos that are based on the Adobe RGB Gamut. The Adaptive Display screen mode provides significantly more Vivid and Saturated Colors. Some people like that. The Adaptive Display screen mode is also recommended for viewing in medium to high levels of ambient light because it offsets some of the reflected light glare that washes out the image colors, which is demonstrated in this Figure for ambient light levels up through 2,000 lux.

· Display Related Enhancements

· The Galaxy S8 is IP68 water resistant in up to 5 feet of water for up to half an hour, which means you can comfortably view the display in typical wet indoor and outdoor conditions – even carefully use it in a tub or shower, and it should be fine if you accidentally drop it in a sink or toilet.

· The Galaxy S8 can be used with Polarized Sunglasses in both the Portrait and Landscape orientations unlike LCDs, which generally work in only one of the two orientations.

· The Galaxy S8 has the new Gorilla Glass 5, which provides much higher resistance to breakage.

· The Galaxy S8 accepts a microSD card, which makes it easier to add large photo and video files.

Galaxy S8 Conclusions: A Very Impressive Smartphone Display…

The primary goal of this Display Technology Shoot-Out article series has always been to publicize and promote display excellence so that consumers, journalists and even manufacturers are aware of and appreciate the very best in displays and display technology. We point out which manufactures and display technologies are leading and advancing the state-of-the-art for displays by performing comprehensive and objective scientific Lab tests and measurements together with in-depth analysis. We point out who is leading, who is behind, who is improving, and sometimes (unfortunately) who is back pedaling… all based solely on the extensive objective careful Lab measurements that we also publish, so that everyone can judge the data for themselves as well…

OLED Display Evolution

What is particularly significant and impressive is that Samsung has been systematically improving OLED display performance with every Galaxy generation since 2010, when we started tracking OLED displays. The first notable OLED Smartphone, the Google Nexus One, came in decidedly last place in our 2010 Smartphone Display Shoot-Out. In a span of just seven years mobile OLED display technology now has a commanding first place lead and continues pushing ahead aggressively. The Galaxy S8 continues the impressive improvements in mobile OLED displays and technology.

The Best Smartphone Display

The Galaxy S8 is the first in a new generation of OLED Smartphones that have a Full Screen Display design. It has many major and important state-of-the-art display performance enhancements, features and functions, with mobile OLED display technology now advancing faster than ever. The Galaxy S8 is the most innovative and high performance Smartphone display that we have ever lab tested. So the Galaxy S8 becomes the Best Performing Smartphone Display, earning DisplayMate’s highest ever A+ grade.

See the Display Shoot-Out Comparison Table section below for the complete DisplayMate Lab measurements and test details.

See the Highlights and Performance Results section above for a detailed overview with expanded discussions and explanations.

See the Display Assessments section for the evaluation details.

The Galaxy S8 has the following enhanced state-of-the-art display performance functions and features:

· A radical new Full Display Screen design that fills almost the entire front face of the phone providing a significantly larger display for the same phone size.

· A curved screen OLED display that is manufactured on a flexible plastic substrate so that it can bend around corners on both sides of the phone to provide two curved Edge Display areas that can be viewed and controlled from both the front or the sides.

· A new larger 5.8 inch Full Screen Display that fills almost the entire front face of the Galaxy S8 from edge-to-edge. Its display is 18% larger in screen area than the Galaxy S7, with almost exactly the same width but 17% taller. The Home button and Navigations buttons are now incorporated within the touchscreen display.

· A new display form factor with a taller height to width Aspect Ratio of 18.5 : 9 = 2.05, which is larger than the 16 : 9 = 1.78 on the Galaxy S7 (and widescreen TVs) because the display now has the same overall shape as the entire phone. It is taller in Portrait mode and wider in Landscape mode. This provides extra space for Notifications and for multiple windows and content.

· 4 Color Gamuts and 3 Calibrated Screen Modes with High Absolute Color Accuracy based on our extensive Lab Measurements.

· A new larger full 100% DCI-P3 Color Gamut and Digital Cinema mode that is also used for 4K Ultra HD TVs, so the Galaxy S8 can display the latest high-end 4K video content. The DCI-P3 Gamut is 26 percent larger than the Rec.709 Gamut that is used in 2K Full HD TVs.

· The Galaxy S8 is the first Smartphone to be certified by the UHD Alliance for Mobile HDR Premium, which allows the Galaxy S8 to play the same 4K High Dynamic Range content produced for 4K UHD Premium TVs.

· A larger Native Color Gamut with a new high saturation “Deep Red” OLED, resulting in a very impressive 113% of DCI-P3 and 142% of sRGB / Rec.709 Gamuts that also provides much better on-screen Colors in High Ambient Light.

· A 3K Higher Resolution 2960 x 1440 Quad HD+ display with 570 pixels per inch, and Diamond Pixels with Sub-Pixel Rendering.

· A Video Enhancer that provides HDR-like Expanded Dynamic Range for all videos that don’t have HDR coding.

· A record high Peak Brightness of over of 1,000 nits, which improves screen visibility in very high Ambient Light, and provides the high screen Brightness needed for HDR.

· Front and back Dual Ambient Light Sensors for significantly improved Automatic Brightness settings.

· A Night Mode with a Blue Light Filter that allows the user to adjust and reduce the amount of blue light from the display for better night viewing and improved sleep.

· A user adjustable White Point with RGB Color Balance slider controls that can change the color of White for the Adaptive Display screen mode.

· An Always On Display mode and Personalized Auto Brightness Control that were first introduced on the Galaxy S7.

· Small Color Shifts and Brightness Shifts with Viewing Angle.

· The Galaxy S8 can be used with Polarized Sunglasses in both the Portrait and Landscape orientations unlike LCDs, which generally work in only one of the two orientations.

· A new and even stronger curved Gorilla Glass 5 protecting the display.

The Galaxy S8 matches or sets new Smartphone display performance records for:

· Largest Native Color Gamut (113% DCI-P3 and 142% sRGB / Rec.709).

· Highest Peak Brightness (1,020 nits).

· Highest Contrast Rating in Ambient Light (227).

· Highest Screen Resolution 3K (2960x1440).

· Highest (infinite) Contrast Ratio.

· Lowest Screen Reflectance (4.5 percent).

· Smallest Brightness Variation with Viewing Angle (29 percent).

· Almost every display lab test and measurement shows some improvements compared to the Galaxy S7.

The Best Smartphone Display

The Galaxy S8 delivers uniformly consistent all around Top Tier display performance and receives All Green (Very Good to Excellent) Ratings in all of the DisplayMate Lab test and measurement Categories (except for a single Yellow in Brightness Variation with Average Picture Level that applies to all OLED displays). See the Display Shoot-Out Comparison Table below for all of the measurements and details. So the Galaxy S8 becomes the Best Performing Smartphone Display that we have ever lab tested, earning DisplayMate’s highest ever A+ grade. See the Display Assessments section for the evaluation details.

The Future of OLED Smartphones

The Galaxy S8 is the first in a new generation of OLED Smartphones. OLEDs have now evolved and emerged as the premium mobile Smartphone display technology. There is no better confirmation of this than a series of well founded rumors from a number of prominent publications that Apple will be switching its top-of-the-line iPhone model to an OLED display in 2017. More than two dozen manufacturers already make OLED Smartphones, and the new Full Screen Display design using a flexible OLED will be the new Flagship for all the upcoming future Top Tier Smartphones.

LCDs are a great cutting edge high performance display technology for Tablets to TVs, but for small handheld Smartphones, OLED displays provide a number of significant advantages over LCDs including: being much thinner, much lighter, without needing a bezel providing a rimless edge-to-edge design. They can be made flexible and into curved screens, plus they have a very fast response time, better viewing angles, and an always-on display mode. Many of the OLED performance advantages result from the fact that every single sub-pixel in an OLED display is independently directly electrically powered to emit light, so only the active image sub-pixels draw power based on their individual brightness levels. OLEDs can also provide better color accuracy, image contrast accuracy, and screen uniformity because of variations in the Backlights of LCDs.

As the result of their very versatile power management capabilities, OLEDs are not only more power efficient than LCDs for most image content, but they now deliver much higher peak Brightness than LCDs because the maximum power can delivered to just the sub-pixels that are needed for producing the current image. However, for mostly all white screen content LCDs are likely to remain brighter and more power efficient for a while.

OLED displays are also manufactured on flexible substrates that can bend, which allows the screens to be curved and rounded and provides a number of innovative new screen geometries. The most popular one is expanding the front main screen so that it extends around to both the right and left sides of the phone by bending around the corners like on the Galaxy S8, and on earlier Galaxy Edge and Galaxy Round models.

The main production and availability issue for the next several years will be that the demand for OLED displays will significantly exceed the manufacturing capacity as we discuss in Flagship 2017 OLED Smartphones.

Improving the Next Generation of Mobile Displays

The Galaxy S8 has a very high resolution 3K 2960x1440 pixel display with 570 pixels per inch (ppi) producing images that look perfectly sharp with normal 20/20 Vision under all normal viewing conditions, which always includes some ambient light that always lowers the visible image contrast and perceived image sharpness (Modulation Transfer MTF). Note that displays are almost never viewed in absolute darkness under perfect viewing conditions with ideal image content. Some clueless reviewers have been pining for 4K 3840x2160 Smartphones, which would require almost double the pixels, memory, and processing power of the 2960x1440 display on the Galaxy S8, but there would be no visual benefit for humans! As a result, it is absolutely pointless to further increase the display resolution and pixels per inch (ppi) for a marketing wild goose chase into the stratosphere...

With screen size and resolution already functionally maxed out, manufacturers should instead dedicate their efforts and resources into improving real world display performance in ambient light by using advanced technology to restore and compensate for the loss of color gamut, color saturation, and image contrast due to ambient light, something that every consumer will benefit from, and will also immediately notice and appreciate – providing a true sales and marketing advantage…

The most important improvements for OLED and LCD mobile displays will come from improving their image and picture quality and screen readability in real world ambient light, which washes out the screen images, resulting in reduced image contrast, color saturation, and color accuracy. The key will be in lowering the Screen Reflectance and implementing Dynamic Color Management with automatic real-time modification of the display’s native Color Gamut and Dynamic Intensity Scales based on the measured Ambient Light level in order to have them compensate for the reflected light glare and image wash out that causes a loss of color saturation and image contrast from ambient light as discussed in our Innovative Displays and Display Technology and SID Display Technology Shoot-Out articles.

The displays, technologies, and manufacturers that succeed in implementing this new real world high ambient light performance strategy will take the lead in the next generations of mobile displays… Follow DisplayMate on Twitter to learn about these developments and our upcoming display technology coverage.

DisplayMate Display Optimization Technology

All Smartphone, Tablet, Monitor and TV displays can be significantly improved using DisplayMate’s proprietary very advanced scientific analysis and mathematical display modeling and optimization of the display hardware, factory calibration, and driver parameters. We help manufacturers with expert display procurement, prototype development, display performance improvement and optimization, testing displays to meet contract specifications, and production quality control so that they don’t make mistakes similar to those that are exposed in our public Display Technology Shoot-Out series for consumers. This article is a lite version of our advanced scientific analysis – before the benefits of our DisplayMate Display Optimization Technology, which can correct or improve all of these issues. If you are a display or product manufacturer and want to significantly improve display performance for a competitive advantage then Contact DisplayMate Technologies.

Galaxy S8

Display Shoot-Out Comparison Table

Below we examine in-depth the OLED display on the Samsung Galaxy S8 based on objective Lab measurement data and criteria

in the following sections: Display Specifications, Overall Assessments, Screen Reflections, Brightness and Contrast,

Colors and Intensities, Viewing Angles, OLED Spectra, Display Power.

For additional background and comparison information see the earlier article covering the Galaxy S7 Display Technology Shoot-Out.

Detailed Test and Measurement Comparisons between the Galaxy S8 and Galaxy S7

You can directly compare the data and measurement results for the Galaxy S8 with the Galaxy S7 display in detail

by using a Tabbed web browser with our comprehensive Lab measurements and analysis for each of the displays.

For each Tab click on a Link below. The entries are mostly identical with only minor formatting differences,

so it is easy to make detailed side-by-side comparisons by simply clicking through the Tabs.

Samsung Galaxy S8 Lab Measurements Comparison Table

Samsung Galaxy S7 Lab Measurements Comparison Table

For comparisons with the other leading Smartphone, Tablet, and Smart Watch displays see our Mobile Display Technology Shoot-Out series.

About the Author

Dr. Raymond Soneira is President of DisplayMate Technologies Corporation of Amherst, New Hampshire, which produces display calibration, evaluation, and diagnostic products for consumers, technicians, and manufacturers. See www.displaymate.com. He is a research scientist with a career that spans physics, computer science, and television system design. Dr. Soneira obtained his Ph.D. in Theoretical Physics from Princeton University, spent 5 years as a Long-Term Member of the world famous Institute for Advanced Study in Princeton, another 5 years as a Principal Investigator in the Computer Systems Research Laboratory at AT&T Bell Laboratories, and has also designed, tested, and installed color television broadcast equipment for the CBS Television Network Engineering and Development Department. He has authored over 35 research articles in scientific journals in physics and computer science, including Scientific American. If you have any comments or questions about the article, you can contact him at dtso.info@displaymate.com.

DisplayMate Display Optimization Technology

All Smartphone, Tablet, Monitor and TV displays can be significantly improved using DisplayMate’s proprietary very advanced scientific analysis and mathematical display modeling and optimization of the display hardware, factory calibration, and driver parameters. We help manufacturers with expert display procurement, prototype development, display performance improvement and optimization, testing displays to meet contract specifications, and production quality control so that they don’t make mistakes similar to those that are exposed in our public Display Technology Shoot-Out series for consumers. This article is a lite version of our advanced scientific analysis – before the benefits of our DisplayMate Display Optimization Technology, which can correct or improve all of these issues. If you are a display or product manufacturer and want to significantly improve display performance for a competitive advantage then Contact DisplayMate Technologies.

About DisplayMate Technologies

DisplayMate Technologies specializes in proprietary advanced scientific display calibration and mathematical display optimization to deliver unsurpassed objective performance, picture quality and accuracy for all types of displays including video and computer monitors, projectors, TVs, mobile displays such as Smartphones and Tablets, and all display technologies including LCD, OLED, 3D, LED, LCoS, Plasma, DLP and CRT. This article is a lite version of our intensive scientific analysis of Smartphone and Smartphone mobile displays – before the benefits of our advanced mathematical DisplayMate Display Optimization Technology, which can correct or improve many of the display deficiencies. We offer DisplayMate display calibration software for consumers and advanced DisplayMate display diagnostic and calibration software for technicians and test labs.

For manufacturers we offer Consulting Services that include advanced Lab testing and evaluations, confidential Shoot-Outs with competing products, calibration and optimization for displays, cameras and their User Interface, plus on-site and factory visits. We help manufacturers with expert display procurement, prototype development, and production quality control so they don’t make mistakes similar to those that are exposed in our Display Technology Shoot-Out series. See our world renown Display Technology Shoot-Out public article series for an introduction and preview. DisplayMate’s advanced scientific optimizations can make lower cost panels look as good or better than more expensive higher performance displays. If you are a display or product manufacturer and want to turn your display into a spectacular one to surpass your competition then Contact DisplayMate Technologies to learn more.

Article Links: Galaxy S7 OLED Display Technology Shoot-Out

Article Links: Display Color Gamuts Shoot-Out NTSC to Rec.2020

Article Links: Absolute Color Accuracy Display Technology Shoot-Out

Article Links: Watching Displays at Night

Article Links: Display Technology Shoot-Out Article Series Overview and Home Page

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