Introduction

It's only been about 7 months since we tested Samsung's first Plane to Line Switching (PLS) technology screen, the 27" S27A850D. This represented a new venture for Samsung who had for a long time invested in TN Film and their own Patterned Vertical Alignment (PVA) panel technology. However, due to the ever-growing popularity of IPS panels which were seemingly starting to dominate the market, Samsung have instead moved their focus onto development of this PLS technology as an alternative. There have only been a few screens released so far featuring PLS panels, but the initial release of the S27A850D (or SA850 as it is sometimes called) impressed us in many regards.

Now Samsung have decided to update the model, offering this time something a little bit different. The new S27B970D (or SB970 as it's more commonly known) is again a PLS-based screen, but is aimed more at the professional end of the market. It features some very impressive specs and features and carries a price tag reserved more for the high-end offerings from the likes of NEC and Eizo. This is Samsung's first effort to compete with those pro-grade models with a PLS panel and so it's an interesting step in the development of the technology. Of particular interest here is the glossy screen coating, high end sleek design, factory calibration, hardware calibration support and uniformity correction. It will be interesting to see how this screen compares with the more mainstream SA850 model, and whether it can really offer the top-end performance you'd expect for the price point.

Samsung's website states: "Each manually calibrated Series 9 Monitor undergoes an expert, hour-long adjustment process before it reaches your home or office ensuring you get the highest-quality images right out of the box. And once it's yours the built-in calibration engine enables in-home adjustments for the perfect picture every time. The slim profile and sleek design of the Series 9 Monitor boasts a sophisticated frame in front and a shimmering panel in back. The slim bezel and crystal-clear glass hidden-panel display create a stunning look, while the solid metal frame adds an elegant touch. Even when it's switched off, Series 9 is sure to be the focal point of the room."

Specifications and Features

The following table gives detailed information about the specs of the screen:

Manufacturers website link: Samsung

The S27B970D offers a very good range of video connections which is great to see and I suppose should be expected given the cost and position of this screen in their range. There are HDMI v1.4, Dual-link DVI-D and DisplayPort provided for video interfaces. With the screen offering a 2560 x 1440 resolution though only the DL-DVI and DisplayPort connections can support the full resolution due to bandwidth limitations over HDMI. It is nevertheless nice to see HDMI provided for users who want to connect other devices, particularly external Blu-ray and DVD players. No D-sub VGA port is provided on this model. The digital interfaces are HDCP certified for encrypted content. The screen comes packaged in the UK with a dual-link DVI, DisplayPort, MHL (HDMI to micro 5 pin) and USB 2.0 cables. An external power brick and cable is also provided along with a handy cleaning cloth. According to the manual the accessories may vary from country to country. There is no HDMI cable supplied here though.

MHL is a new connectivity option which is starting to appear on a few monitors. It allows you to connect an MHL-supporting mobile or tablet device to the screen and view videos and photos saved on the device via your screen. It also charges the device while connected which is useful.

There are 2x USB 2.0 ports available and the screen features 2x 7W integrated stereo speakers. Samsung's website explains: "With a built-in Samsung Stereo Speaker, a 5 Way Speaker delivers high-quality stereo sound and a richer multimedia experience. You�ll enjoy enhanced movies and music, as if you were in a theatre or concert, thanks to Samsung�s outstanding audio. Experience total convenience and make the most of home or office space with cost-efficient built-in speakers." In addition the screen features hardware level calibration support from its 16-bit LUT and uniformity, gamma and colour coordinate correction technologies.

Below is a summary of the features and connections of the screen:

 

OSD Menu

 
Above: view of OSD operational buttons

The OSD menu is controlled through a series of touch sensitive buttons located on the bottom of the monitor arm. The buttons glow a subtle white colour when the screen is powered on. In standby the power button flashes on and off in the same white colour. Depending on the height of the screen and the height of the user, you may not see some of these buttons from your normal viewing position. The sensitivity of the buttons is very good and they function very well. They again help give a premium feel to this screen.

There is quick access to the 'Color mode' menu by pressing the down arrow button, which is also identified with the little three circles logo. The up arrow label gives you quick access to the brightness and contrast controls when the screen is connected via DVI. When connected via HDMI or DisplayPort this is instead a quick access to the volume control for the integrated speakers. On the left, the top button switches quickly between the video inputs and the bottom button brings up the main OSD menu.

The main menu itself is divided into 5 sections which are shown down the left hand side. As you scroll up and down the right hand side of the menu software shows you some of the options which are available in each section. Above shows the information section for reference. Pressing the enter button takes you into a specific section and the software then switches to a view of the specific options for that section.

The first section is the 'picture' section. This includes the normal options for brightness and contrast as you might expect. There is also control over the dynamic contrast ratio, response time control and HDMI black level (used to help with degraded picture quality and contrast when connecting DVD players and set top boxes via HDMI). Some of these options will be greyed out depending on your connection type and the preset mode you are in.

The second section is the 'color' menu. Here you can choose the preset 'color mode' as shown above. You can also control the individual RGB channels in each preset.

The color temp. menu offers a massive range of pre-defined colour temperature modes as shown above. Likewise the gamma menu allows you to define the gamma curve with a wide range of options available. We will test all of these a little later on.

The size & position section is the third section. You can control the hardware level aspect ratio control here (we will look at this a little later on as there are also some other options here), and various aspects of the OSD software itself.

The setup & reset section offers you a few extra controls. You can turn the ECO saving feature on here as shown above. You can also control the input selection and a few other basic settings.

Scrolling down in this section reveals a few other options related to power saving.

All in all the menu was easy and intuitive to navigate. There was a decent range of options, particularly with the control of colour temperature and gamma which we will test in a moment. The touch sensitive buttons and their appearance gave a premium feel to the menu as well which was nice. The only slightly confusing thing was that you had to enter the screen using one button, but pressing it again would close the menu again. Once in the menu you had to use the top button to 'enter' or select an option.

 

Power Consumption

In terms of power consumption the manufacturers spec states typical usage of 53W without anything connected to the USB ports. A maximum usage of 63W is also specified when USB ports are in use. In standby the screen apparently uses <0.5W.

We tested this ourselves and found that out of the box the screen used 46.9W of power while at its default brightness setting which was 100%. At the lowest brightness setting, power consumption was reduced to 22.8W. After calibration the brightness had been set at 27% (in the High Bright preset) to achieve the desired luminance and this returned a power consumption of 29.1W. In standby the screen used 1.0W of power.

We also tested the ECO mode options available in the menu. They are affectively preset and locked brightness settings which seem to correspond to brightness settings of 75% and 50%. The power consumption of each is shown above. If you use either of these modes the main brightness control is greyed out.

I have plotted the results of these measurements on the graph below. You can see power consumption is pretty much identical to the S27A850D model and both are considerably lower than some CCFL based units (e.g. NEC PA271W) when calibrated to the same luminance. This is an advantage of W-LED backlighting:

 

Panel and Backlighting

The Samsung S27B970D utilises a Samsung LTM270DL02-201 Plane to Line Switching (PLS) panel which is capable of producing 16.7 million colours with a true 8-bit colour depth. Some early information about the screen had suggested that the panel would offer 1.07 billion colours through a "10-bit" panel but it seems this has changed with the final release. All Samsung's spec pages confirm the screen offers a 16.7 million colour palette. In addition, we know from studying the detailed panel spec sheet for this particular module that it is an 8-bit panel.

Above: dismantled view of the screen. Click for larger version

It is possible to dismantle the S27B970D by unscrewing the bottom metal edge of the screen. We did this to investigate the internal electronics and confirm the specific panel part being used.

Above: stickers labelling the panel in the screen. Click for larger versions

The stickers on the panel as shown above confirm it is using the LTM270DL02 panel and it looks as though this is classified as the 201 revision from what we can tell. This would suggest some minor changes since the panel used in the S27A850D which would fit in with differences to the specs of the two models.

Above: etchings on metal frames of the screen identifying panel part. Click for larger versions

The metal bracket which holds the panel in place at the top (See top picture showing full view of the dismantled screen) has the above label etched into the metal, saying "LTM270DL02-D01". This would actually fit in more with Samsung's previous naming scheme for their panels as opposed to the "201" suffix. However, the panel stickers seem to suggest it is a 201 revision so we will assume that is most accurate for now. The panel part is also etched onto the metal on the front of the screen which is hidden behind the protective glass front panel.
 

The S27B970D uses White-LED (W-LED) backlighting producing a colour space approximately equal to the sRGB reference. This means the screen is considered a 'standard gamut' backlight type. Studying the detailed panel spec sheet confirms that the colour space is equal to 81% of the NTSC space, 78.1% of the Adobe RGB reference and 99.5% of the sRGB space. A wide gamut screen would need to be considered by those wanting to work outside of the sRGB colour space of course. This coverage is actually a little wider than some other W-LED units which can typically cover ~70% of the NTSC space. An emulation mode is provided if you want to strictly match the sRGB space which we will look at shortly.

 

PWM Flicker Tests at Various Backlight Brightness Settings

100%                                                50%                                                      0%

We tested the screen to establish the methods used to control backlight dimming. Our recent article talks in more details about a common method used for this which is called Pulse Width Modulation (PWM). A series of photos was taken using the method outlined in the article. These were taken at 100%, 50% and 0% brightness settings. This allows us to establish 1) whether PWM is being used to control the backlight, 2) the approximate frequency at which this operates, and 3) whether a flicker may be introduced or potentially noticeable at certain settings.

A thin white line was shown on an all-black background and a photograph was taken at a slow shutter speed of 1/8 second (in this example) as the camera was scanned left to right in front of the screen. This produces a series of white lines which can be used to identify the frequency of the PWM and how quickly the backlight is cycled on and off. The higher this frequency, the less likely you are to see artefacts and flicker. The duty cycle (the time for which the backlight is on) is also important and the shorter the duty cycle, the more potential there is that you may see flicker. Please remember that not every user would notice a flicker from the backlight but it is something to be wary of. It is also a hard thing to quantify as it is very subjective when talking about whether a user may or may not experience the side effects. We are able to at least measure the frequency of the backlight using this method and tell you whether the duty cycle is sufficiently short at certain settings that it may introduce a flicker to those sensitive to it.

Interestingly the Samsung S27B970D appears to not use PWM at all for dimming of the backlight. Even at 0% brightness there was no sign of the usual splitting of the white line that you'd expect to see in these tests. We carried out the checks at a even slower shutter speeds which returned the same result. This is great news for those who are affected by flickering backlights and suffer from eye fatigue and eye strain. There are very few monitors which don't use PWM for backlight dimming (the HP ZR2740w and DGM IPS-2701WPH spring to mind as others), but this model does not.

 

Factory Calibration

According to Samsung's specifications, the S27B970D "undergoes an expert hour-long adjustment process before it reaches your home or office, ensuring you get the highest quality images right out of the box". The manual states that the standard and sRGB preset modes have been factor calibrated. The screen should come packaged with a Samsung "Natural Color Expert Data Sheet" giving you a report of the calibration done in the factory. This confirms the unit has passed the grey balance, uniformity correction and gamma correction tests. It also confirmed the white point and gamma curve along with the dE colour difference across the entire grey range.

 

Above: Sample duplicated calibration report card (not from our unit). Image courtesy of colormgmt.com

 

Unfortunately in the review sample of the screen we received this report was missing, presumably lost somewhere along the way. Nevertheless, it is of course more important to find out how the default setup is in real life, and so our tests in the next section will establish the default setup in some of the main preset modes. That will allow us to establish the quality of the factory setup for ourselves.

 

Updated 5th September 2012

 

I did want to briefly touch on a report which was brought to our attention relating to the factory report cards shipped with the screen. It seems that the report cards for that were originally being shipped with this screen may have be mass produced. Many different samples appeared to have the exact same numbers and results on them when compared. Some more information is available about this at colormgmt.com with photos of several reports, all from different screen samples with differing serial numbers. We have provided an example of this card above for reference, note that it's not from our unit as there was not one provided. It would seem to suggest that Samsung had just printed the same report for each unit to try and demonstrate the factory calibration, but each report is not unique to the specific unit you have. Maybe this is just supposed to be a representation of their apparent factory calibration process, or a way to tell you what setup they have gone for, but one would have hoped really for a unique report for the specific screen as you get with some other screens (e.g. Dell U2410, U2711, U3011 series). It perhaps brought into question the quality of the factory calibration if they did not want to spend the time producing unique reports for each sample.

 

Above: sample updated calibration report (note: not from our unit)

 

Since writing this review we have however received an update on the matter. We received the above sample of a calibration report from the S27B970D from one of our readers. After discussing this with Howard Kim at colormgmt.com we established that Samsung have actually updated the factory calibration reports since, and perhaps because of his original article. This is positive news and should mean the calibration reports received are specific to your sample unit.

 

Testing Methodology

An important thing to consider for most users is how a screen will perform out of the box and with some basic manual adjustments. Since most users won't have access to hardware colorimeter tools, it is important to understand how the screen is going to perform in terms of colour accuracy for the average user.

I restored my graphics card to default settings and disabled any previously active ICC profiles and gamma corrections. The screen was tested at default factory settings using the DVI interface, and analysed using an X-rite i1 Pro Spectrophotometer (not to be confused with the new i1 Display Pro colorimeter) combined with LaCie's Blue Eye Pro software suite. An NEC branded and customised X-rite i1 Display 2 colorimeter was also used to verify the black point and contrast ratio since the i1 Pro is less reliable at the darker end.

Targets for these tests are as follows:

• CIE Diagram - validates the colour space covered by the monitors backlighting in a 2D view, with the black triangle representing the displays gamut, and other reference colour spaces shown for comparison

• Gamma - we aim for 2.2 which is the default for computer monitors

• Colour temperature / white point - we aim for 6500k which is the temperature of daylight

• Luminance - we aim for 120 cd/m², which is the recommended luminance for LCD monitors in normal lighting conditions

• Black depth - we aim for as low as possible to maximise shadow detail and to offer us the best contrast ratio

• Contrast ratio - we aim for as high as possible. Any dynamic contrast ratio controls are turned off here if present

• dE average / maximum - as low as possible. If DeltaE >3, the color displayed is significantly different from the theoretical one, meaning that the difference will be perceptible to the viewer. If DeltaE <2, LaCie considers the calibration a success; there remains a slight difference, but it is barely undetectable. If DeltaE < 1, the color fidelity is excellent.

 

Default Performance and Setup

Default settings of the screen were as follows:

Samsung S27B970D - Default Factory Settings, Standard Mode

   

 

The default set of the screen actually felt very good to the naked eye. Colours felt even and not too cold, not too warm. The brightness was a bit high but not blindingly so, even at maximum brightness. The image looked good to the naked eye, and colours and blacks "popped" thanks to the use of a glossy screen coating. In terms of measurements, the CIE diagram on the left confirms that the monitors colour gamut (black triangle) matches the sRGB colour space (orange triangle) reasonably closely. It extends a little past the sRGB space in some blues and reds in particular in this 2D view of gamut which fits in with the fact we know it can cover ~81% of the NTSC colour space, and so extends beyond sRGB slightly. There is pretty much no under-coverage of the sRGB reference space and we know from the panel spec that it can cover 99.5% of the sRGB reference which is great.

 

 

Default gamma was recorded at 2.2 average, leaving it only 1% out from the target of 2.2 which was great. The gamma was a little too high in lighter grey tones where it ranged up to 2.21 maximum which is hardly a big difference. A very good default gamma setup from the screen which was good news. White point was also very close to the target, being recorded at 6438k and being only 1% out from 6500k. Note that we are using a spectrophotometer to make these measurements which is not sensitive to the W-LED backlight as some colorimeter devices can be. When using a standard gamut colorimeter not designed to work with modern backlighting units like W-LED, there can be a typical deviance of 300 - 600k in the white point measurement which is why some sources may refer to a different white point in this test incorrectly.

 

Luminance was recorded at a pretty high 249 cd/m² which is too bright for continued use. The black depth was a reasonable 0.35 cd/m², giving us an adequate static contrast ratio of 711:1. This was behind some competing IPS panels, and certainly not to the standards of VA matrices, but it's still not too bad for most users. I would also add that the presence of a glossy screen coating does make blacks pop and does improve perceived black depth. Colour accuracy was pretty good at default factory settings with an average DeltaE (dE) of 2.6, ranging up to a maximum of 6.7. Along with the very good gamma and white point, this factory setup was very good really, and the factory calibration seemed reliable out of the box. The gamma and white point target in particular were well met. You can of course alter the luminance simply by adjusting the brightness control.

 

Samsung S27B970D - Default Factory Settings, High Bright Mode

   

 

We also carried out tests to establish the default setup in some of the other preset modes. We tested the 'High Bright' mode first of all. The colour temperature and gamma settings were not available in this mode, but you still had control over the RGB channels if you want. When switching to this mode from the standard preset, you do see a jump in the luminance of the screen. The luminance was now measured at 283 cd/m², which was a little higher than the 249 cd/m² we'd seen in the standard mode. This was as per the Samsung spec which claimed a higher brightness (of 285 cd/m²) in the High Bright mode than in standard. Note that the OSD brightness control was 100% in both cases, so this preset just gives you an additional bump in brightness. Black point remained as we had measured before at 0.35 cd/m², so in fact this mode gave us a higher static contrast ratio of 828:1 which was pleasing.

 

Gamma and white point remained very accurate really although colour accuracy was not quite as good with dE average now 3.4 and some big differences in blue shades where dE ranged up to 10.5. The manual suggests that this mode does not carry the factory calibration process (only the standard and sRGB modes), but nevertheless performance was reliable in terms of gamma and white point, although the colour accuracy was not quite as well set up in this mode.

 

 

Samsung S27B970D - Default Factory Settings, sRGB Mode

   

 

We also tested the screen in the sRGB preset mode. This preset was more locked down in terms of OSD settings. You could alter the brightness still, but contrast, RGB channels, colour temperature and gamma were all not available. The default brightness in this preset was 50% as well. Interestingly this preset offered a pretty reliable emulation of the sRGB colour space, reducing the native gamut of the screen pretty well. The black triangle representing the monitors gamut now closely matched the sRGB reference in the CIE diagram on the left, helping to cut back any oversaturation you might see in the other preset modes.

 

 

Gamma and white point remained very accurate and were both 0% out from the target which was excellent. Colour accuracy was also excellent and this preset showed a great factory calibration in that regard. dE average was now 1.1 and maximum was 2.7. The only issue with this mode was that the contrast ratio seemed to be crushed quite a lot. We measured a luminance of 154 cd/m² now with the screen at 50% brightness, but black depth remained at 0.34 cd/m². This gave us a static contrast ratio of 457:1 which was poor.

 

 

 

Testing Colour Temperatures and Gamma

 

 

The S27B970D features a huge range of colour temperature presets within the OSD 'Color temp' menu as shown above. We measured the screen with the X-rite i1 Pro spectrophotometer in each of the preset modes to establish their colour temperature / white point. All other settings were left at factory defaults and no ICC profile was active. The results are recorded below along with the deviance from the target setting.

 

 

 

As you can see, the default and custom settings were very close to a 6500k colour temperature which is the temperature of daylight, and the target we aim for during our calibration process. The warmer colour temp settings then between 4000 and 6500k were very close indeed to their targets, being on average only 18k out. The cooler settings beyond that were a little further away from their targets but nevertheless remains very close. The settings of 7000 - 8000k inclusive were on average only 82k out which is still only around 1 - 2% deviance which is excellent. Even the cooler settings of 8500k and above, which showed a higher deviance still only varied by around 2.5% in the worst cases (-225k difference maximum). Overall these settings seemed very reliable and accurate which was great news for those wanting to work in different colour temperatures.

 

 

 

 

Similarly the OSD contains options for gamma setup, ranging from 1.6 to 2.7. We tested the accuracy of these settings based on a measurement of the average gamma. These were recorded above in the table. As you can see, each preset gamma mode was very accurate and returned a measured average gamma as intended.

 

 

 

Software Calibration Results

 

The Samsung S27B970D may well have a decent factory setting but given the market for this screen I expect many users will want to calibrate the screen personally to obtain even higher levels of accuracy and allow profiling and matching between different devices. Samsung's user manual even includes the compatible type of calibration tools they recommend for use with this screen as shown below. Ultimately you need to ensure you have a device capable of measuring and reading the spectra from the W-LED backlight unit properly. Many older colorimeter devices are designed to work with standard gamut CCFL units only and so they can often have difficulty reading LED (and wide gamut CCFL) units properly. A spectrophotometer does not have this problem and there are also some decent modern colorimeters like the i1 Display Pro which can read W-LED without issue. While you can use other devices and various software packages to complete software profiling of the screen, you may come across issues if the device is not designed to work with a W-LED backlight unit. It should be noted as well that the listed devices here are the only ones supported by Samsung's Natural Color Expert (NCE) software which is needed for hardware calibration.

 

 

The S27B970D offers a hardware calibration engine which can give you very high levels of accuracy and control over the hardware itself. We will test that in a moment, but we also wanted to carry out the usual software level "calibrations" (profiling) at a graphics card level. I used the X-rite i1 Pro spectrophotometer combined with the LaCie Blue Eye Pro software package to achieve these results and reports. An NEC branded and customised X-rite i1 Display 2 was used to validate the black depth and contrast ratios due to lower end limitations of the i1 Pro device.

Samsung S27B970D - Software Calibrated Settings, Standard Preset Mode

Monitor OSD Option	Calibrated Settings
Brightness	38
Contrast	75
Color mode	Standard
RGB Channels	48, 46, 50
Color Temperature	Custom
Gamma	2.2

	Calibrated Settings, Standard mode
luminance (cd/m2)	120
Black Point (cd/m2)	0.18
Contrast Ratio	668:1

 

I remained in the 'standard' preset mode for now. During the process adjustments were made to the brightness and RGB channels as shown in the table above. We left the screen in the default 2.2 gamma mode as we had already established from our gamma tests that this was very accurate and closest to our target of 2.2. When changing the RGB channels the colour temperature changed automatically from 'standard' to 'custom'. Changing the brightness and RGB channels allowed us to obtain an optimum hardware starting point and setup before software level changes would be made at the graphics card level. After this I let the software carry out the LUT adjustments and create an ICC profile.

 

 

Average gamma remained very accurate at 2.2 with 0% deviance according to the initial test. Checking the more detailed table shown above, the average gamma was a little high in dark shades and a little low in light shades, but not by much at all. White point had also been maintained at target with only a very small deviance, now measured at 6521k. Luminance was now spot on at 120 cd/m² thanks to the adjustment of the brightness control as shown. This gave us a moderate black level however of 0.18 cd/m², and a resulting calibrated static contrast ratio of 668:1 which was only a little less than the default performance in this preset mode. I would also add that subjectively the blacks looked good to the naked eye as the glossy screen coating did make them 'pop' and look deep. In reality though the contrast ratio was not as good as other panels we have seen, including some IPS offerings which can reach up to ~1000:1 in some cases. Colour accuracy was improved very nicely though with dE average now only 0.2, and maximum 1.0. LaCie would consider colour fidelity to be excellent overall.

 

Testing the screen with various colour gradients showed mostly very smooth transitions. There was some slight gradation in darker tones and some very, very slight banding introduced due to the adjustments to the graphics card LUT from the profilation of the screen. Nothing major at all though. It's worth also commenting on the screen coating in this section of the review. Unlike most other panels in the market, this screen does not feature the usual grainy and dirty looking anti-glare (AG) coating. Instead it uses a glossy screen coating and as a result the colours look very clean and crisp, the image quality is sharp and whites in particular look a lot more pure than they do on heavy AG coated screens like some of the IPS alternatives available. Glossy coating isn't to everyone's taste though as it can introduce reflections which are annoying. You should probably try and see a glossy and an AG panel in person if you are unsure what to buy.

 

You can use our settings and try our calibrated ICC profile if you wish, which are available in our ICC profile database. Keep in mind that results will vary from one screen to another and from one computer / graphics card to another.

 

 

Samsung S27B970D - Software Calibrated Settings, High Bright Preset Mode

Monitor OSD Option	Calibrated Settings
Brightness	27
Contrast	75
Color mode	High Bright
RGB Channels	45, 45, 50
Color Temperature	n/a
Gamma	n/a

	Calibrated Settings, High Bright mode
luminance (cd/m2)	120
Black Point (cd/m2)	0.15
Contrast Ratio	800:1

 

I switched to the 'High Bright' preset mode to again carry out the software calibration. During the process adjustments were made to the brightness and RGB channels as shown in the table above. Other controls like the colour temperature and gamma were not available in this mode.

 

 

Average gamma remained very accurate at 2.2 with 0% deviance according to the initial test. White point had also been maintained at 1% deviance from the target, now measured at 6539k. Luminance was spot on at 120 cd/m² thanks to the adjustment of the brightness control as shown. This gave us a very good black level however of 0.15 cd/m², and a resulting calibrated static contrast ratio of 800:1 which was pleasing. Colour accuracy was now excellent in this mode as well, with average dE 0.3 and maximum of 1.5. LaCie would consider colour fidelity to be excellent and certainly a nice correction compared with the default setup in this mode. Colour gradients again showed mostly very smooth transitions with some slight gradation in darker tones and some very, very slight banding introduced due to the adjustments to the graphics card LUT from the profilation of the screen. Nothing major at all though. Given the elevated static contrast ratio in this mode, it seems to be the logical choice for a calibrated preset mode if you are carrying out this kind of profiling of the screen. By default, it had not been great in terms of colour accuracy as it lacked the full factory calibration by Samsung in that mode. If you have access to a calibration tool and can improve that, then the improved contrast ratio compared with the other preset modes is welcome.

 

You can use our settings and try our calibrated ICC profile if you wish, which are available in our ICC profile database. Keep in mind that results will vary from one screen to another and from one computer / graphics card to another.

 

 

Samsung S27B970D - Software Calibrated Settings, sRGB Preset Mode

Monitor OSD Option	Calibrated Settings
Brightness	37
Contrast	n/a
Color mode	sRGB
RGB Channels	n/a
Color Temperature	n/a
Gamma	n/a

	Calibrated Settings, sRGB mode
luminance (cd/m2)	120
Black Point (cd/m2)	0.28
Contrast Ratio	429:1

 

I switched to the 'sRGB' preset mode to again carry out the software calibration. This had proved to have a very good factory calibration in nearly every way, including a reliable emulation of the sRGB colour space which was pleasing. During the process adjustments were made to the brightness only, since all the other options including the RGB channels were not available.

 

 

Average gamma remained very accurate at 2.2 with 0% deviance according to the initial test. White point had also been maintained at 1% deviance from the target, now measured at 6546k. Luminance was now spot on at 120 cd/m² thanks to the adjustment of the brightness control as shown. This gave us a weak black level however of 0.28 cd/m², and a resulting calibrated static contrast ratio of 429:1. With no access to the contrast or RGB channels at the hardware level it is not possible to change this unfortunately. Colour accuracy was now excellent in this mode as well, even more so than the very good factory calibration, with average dE 0.3 and maximum of 1.5. Colour gradients again showed very smooth transitions with some slight gradation in darker tones and not noticeable banding at all. While the sRGB mode offers a nice emulation of a smaller colour space, has a very good factory calibration and can offer some even more accurate performance once calibration, it remains weak when it comes to contrast ratio. I'm not sure why this has been crushed so much during the default settings but it's a shame.

 

You can use our settings and try our calibrated ICC profile if you wish, which are available in our ICC profile database. Keep in mind that results will vary from one screen to another and from one computer / graphics card to another.

 

 

Software Calibration Summary

 

To summarise the above tests:

• Results are based on normal software level calibration of the screen. Basic OSD adjustments made to obtain optimum hardware starting point, and then profilation of the screen using a calibration tool is carried out. Corrections made at a graphics card LUT level through creation of the ICC profile

• A compatible calibration tool is needed for correct results, it must be able to support W-LED backlight units

• All modes had good default white point and gamma anyway, OSD settings left as they were in those areas

• Brightness adjustment made in each preset to obtain target luminance

• All modes offer excellent colour accuracy after profiling with very low dE values

• Standard mode improved through this process to correct colour accuracy compared with default factory setup

• High Bright preset mode offers the highest static contrast ratio of 800:1 and is therefore probably the best preset to use if you can calibrate at this level. However, without a tool the standard and sRGB modes carry more accurate default colours thanks to factory calibration

• sRGB mode can be calibrated well and offers good emulation of the smaller colour space, but the static contrast ratio remains poor. This seems to be a negative of the particular sRGB preset mode and cannot be corrected through this process
   

 

Hardware Calibration - Natural Color Expert

 

 

The S27B970D features a hardware calibration engine. This means you can, with the right device and software, calibrate the monitor at a hardware Look Up Table (LUT) level. This allows for a far more finite adjustment of the screen for absolute image quality and accuracy. The LUT has a 16-bit bit depth and allows for gamma, uniformity and colour coordinate correction. The specs for the screen state an accuracy of:

• Gray Balance : ΔEab ≤ 1 on sRGB, Calibration Mode

• Uniformity Correction : ΔEab ≤ 3, Luminance > 90% , on Standard, sRGB, Calibration Mode

Hardware calibration is only available using Samsung's own 'Natural Color Expert' (NCE) software. We did test various other software packages including LaCie Blue Eye Pro, iColor Display, and BasICColor Display but none allowed for hardware level adjustment of the monitors LUT, only software level profiling as we have already completed above. The NCE software is available to download for free from Samsung's website. We installed the latest v2.2.0.60 (dated 11 July 2012) of the software under Windows 7. The installation itself was quick and easy and there was nothing really to change. Once installed you must connect the monitor to your PC using the USB connection and cable. You need to have a compatible calibration tool then to make the adjustments and measurements of the display (sold separately), and this needs to be connected into the side USB ports on the base of the screen.

 

 

When you load up the software the screen automatically reverts to the 'calibration' preset mode. In fact you can't then make any changes to the OSD settings, even for brightness or contrast as these are greyed out. You can't even change out of the 'calibration' preset which is strange, although if you turn the monitor off and back on, you can then change back to one of the other preset modes. It seems once the NCE software is loaded though, it locks the screen into the calibration preset and all changes are then made through the software only.

 

 

We loaded up the software as shown above. You are initially presented with the above screen. In the middle would be your saved profiles for the screen once you have created some, and this allows you to switch between them depending on your requirements.

 

 

The preferences menu allows you to take a measurement of the screen in its current state based on the active profile. You can also select whether the creation of a new profile is in the standard or advanced mode. You can also choose the 'preview image' which is shown at the end of a calibration so you can compare the before and after views.

 

 

If you then proceed with a calibration you are first asked to select your calibration device, or connect it if you have not done so already. Here we are using the i1 Pro spectrophotometer again. The drop down only allows for a defined set of compatible devices which we have already discussed earlier on. We tried using other devices including the X-rite i1 Display 2 but they were not recognised.

 

 

Continuing into the calibration process allows you to create a new profile for the monitor, to be stored in its LUT. You can define several settings as shown above, including the luminance, black level, white point and gamma curve. On the left you can also define the gamut (colour space) target although the only option in the drop down for this monitor is sRGB. You can also define specific RGB coordinates if you wish, but there's no option by default to just retain the monitors native gamut oddly. I opted to go with the sRGB gamut although then altered the targets on the right to match our normal review targets. At the bottom you can also define the calibration priority, whether that is "linear grey" or "deep black". You will see fro our tests in a moment that this has quite a profound impact on contrast ratio.

 

 

Continuing with the calibration you are asked to then place the calibrator on the screen in the centre where a box is shown. Pressing next then takes you into an automated process where a series of colours are shown in front of the device for profiling and measurement. There is an odd time indicator at the bottom suggesting how long should be remaining, but it fluctuates and randomly skips between different times so it's not realistic. Overall the process took about 1 minute to complete. You do not make any changes to the screen yourself via the OSD (which is locked when this loads), and all changes and adjustments are made via the software at the hardware LUT level.

 

 

At the end you are presented with a summary screen of the results. You can compare before and after states of 4 photos if you want although that's only providing a very basic visual indication of the changes. There are measurements shown to at least confirm the colour gamut coordinates reached, white point, luminance and gamma. There is also a measurement of the black depth here but since we are using the i1 Pro we have blacked that out as it's inaccurate. The i1 Pro spectrophotometer has a low level accuracy limit of 0.20 cd/m² and so with black depth being below that here (as we've established earlier on in the review with a different device) the number fluctuated massively between different calibration attempts. I've removed it to avoid confusion here. I will validate the contrast ratio separately in a moment. You can then save the calibration profile and you are given the option to load it into the monitor LUT and make it active. That process takes ~13 seconds to load. Checking the graphics card confirms no gamma curves or profiles are active at that level, so all adjustments were indeed made at the hardware LUT level.

 

 

Returning to the main screen shows your saved profile in the list now. For some reason there is no way to quickly switch between saved profiles and change what is loaded into the monitors LUT. You have to complete the calibration process again each time if you want to change settings at all.

 

There are no further test and report functions available to validate your results so you are left having to assume the results are accurate. It would have been nice to see a more advanced test and report process available given this software is designed for us with high end (and expensive) screens. Other than knowing that the white point, gamma and luminance values have been met we don't have any way here to test the colour accuracy for dE values. The screen is entered into the 'calibrated' preset mode where you cannot make any changes affecting the colours, brightness etc in the OSD menu.

Samsung S27B970D - Hardware Calibrated Settings, sRGB gamut

	Calibrated Settings, Hardware sRGB Gamut
luminance (cd/m2)	120
Black Point (cd/m2)	0.19 to 0.29
Contrast Ratio	417:1 to 644:1

 

I instead loaded up the LaCie software to carry out a simple test and report of the calibrated state. There may of course be some subtle differences in the way the software measures everything but it should give us an idea of the new hardware-calibrated state. You can see that the native colour space of the screen has been reduced here to cover more accurately the sRGB gamut. That's a promising sign as we had defined that in the NCE process. Gamma, white point and luminance were all pretty close to the target although the gamma was measured here as being a little too higher in all shades (2.22 to 2.23). The main issue however seemed to be with the colour accuracy. dE was on average 2.7 but there were some significant deviations in some shades, particularly blues. The NCE software had not allowed us to validate the results in this way, but LaCie's software didn't seem to feel accuracy was very good after the hardware calibration.

 

We also tested the black depth and contrast ratio after this calibration using the NEC customised i1 Display 2 device. This has a much lower black level range (0.02 cd/m²) and so can give us a much more accurate contrast ratio measurement than the i1 Pro had. It confirmed contrast ratio was only 417:1 which is a similar result to what we'd seen when we'd software calibrated the screen in the sRGB preset mode. That had involved a hardware level emulation of the smaller sRGB colour space, and a software profile to carry out corrections and profilation of the screen. This was achieved when the priority of the calibration had been selected as "linear grey". Repeating the process with "deep black" as the priority returned a much better contrast ratio of 644:1. Thankfully it seems that you can obtain a better contrast ratio with an sRGB gamut emulation if you hardware calibrate the screen, but the native sRGB preset itself crushed the contrast ratio.

 

 

 

I also carried out a validation using BasICColor Display which gave us similar results as shown above. Some aspects were confirmed as being met reasonably well, but the colour accuracy was poor in some colours. Note, we had asked NCE to calibrate to the sRGB colour space so there was an element of gamut emulation going on here as well, reducing the native gamut slightly to match the sRGB space more closely.

 

So it seemed from these tests that although the NCE software allows for easy calibration of the S27B970D at a hardware level some aspects were achieved well while others were not. It does allow a decent colour space emulation to sRGB, and pretty accurate setup for gamma, white point and luminance. However, resulting colour accuracy was not very good when calibrated to the sRGB gamut.

 

 

We went back into the NCE software to see if we could do any better. While there isn't a specific option to retain the monitors native gamut, you can manually enter the RGB coordinates. We therefore referred to the spec sheet for the LTM270DL02 panel and found the native coordinates as defined for the panel itself. We have provided them above in the screenshot as they appear in the data sheet. You will notice that the colour gamut triangle in the above image is now slightly outside of the sRGB space and looks more like the native gamut measurements we'd seen in our earlier tests. We set the other targets for luminance, white point, black depth and gamma as before and so the only difference was we were asking the screen to calibrate to its native gamut, instead of the sRGB emulation.

 

 

After the calibration process we were presented with the usual NCE confirmation window as shown above. You will note that the resulting colour coordinates are different to our initial calibration in the sRGB mode.

Samsung S27B970D - Hardware Calibrated Settings, Native gamut

	Calibrated Settings, Hardware Native gamut
luminance (cd/m2)	118
Black Point (cd/m2)	0.19 to 0.29
Contrast Ratio	421:1 to 634:1

 

I exited the NCE software and again ran the test and report feature from LaCie's Blue Eye Pro software. This time the results were much different. You can see from the CIE diagram on the left that the colour space measured was now the monitors native gamut and it was not trying to emulate the smaller sRGB colour space as it had before. Gamma, white point and luminance were all pretty close to the targets. Importantly the colour accuracy was now much better with dE 0.6 on average and 1.9 maximum. This was a much better result and it seemed that a hardware calibration to the screens native gamut offered far better results than when it was trying to emulate the smaller sRGB colour space. The tricky thing is you need to manually define the gamut coordinates in the NCE software as there's no option to just maintain the native gamut of the screen on its own. Again we got different results for black depth and contrast ratio depending on whether the NCE calibration process had been set to prioritise linear grey or deep black. The deep black setting returned a much more reasonable calibrated static contrast ratio, closer to what we had achieved during the software calibration of the standard preset mode. We were not able to match the higher contrast ratio achieved through the high bright preset mode though.

 

 

As an additional feature you can also use the NCE software to measure and correct variances in the brightness and colour across the screen. This is available through the screen shown above, where you can define the number of measurement points in your grid. You are then directed to place your calibrator on the screen and move it between each box as it tells you to. The device then takes measurements at each point and corrections are made at a hardware level to ensure an even brightness and colour across the whole screen. We will test the brightness uniformity correction a little later on in the review.

 

 

Hardware Calibration Summary

 

There's a lot to take in there but we will try to summarise the hardware calibration process on the S27B970D.

• Hardware calibration provides higher level of accuracy and control compared with basic software profiling. All adjustments made at the hardware level and so tonal values are maintained

• Samsung's NCE software is the only package which can access the hardware calibration engine. The support for hardware adjustments is therefore not very flexible

• Only a defined set of devices work with the software again giving you limitations

• Software is easy to use on the most part and is pretty quick. It is however missing an option to quickly switch between saved profiles. You have to complete the calibration process again if you want to change anything

• Calibration process allows for reasonable set of targets and process is pretty quick (~1 minute)

• Reporting feature is limited, only really confirming colour coordinates, gamma, white point and luminance. Missing colour accuracy tests and dE measurements

• sRGB emulation is simple through NCE although resulting colour accuracy is poor for some reason (as verified with other software reporting features). We had actually seen better performance from the native sRGB preset mode to be honest.

• Tricky to retain monitors native gamut, you need to manually enter the coordinates which thankfully we obtained from the panel spec sheet

• Calibration at manually defined native gamut of the backlight resulted in better colour accuracy afterwards

• You can define the priority for calibration between "linear grey" and "deep black". The latter produces a much better contrast ratio as measured in our tests in both sRGB and native gamut calibrations

All in all the hardware calibration was ok, although pretty limited in its flexibility and reporting. You can achieve pretty good results when calibrating at the native gamut and with deep black defined as the priority, but sRGB calibration leaves some issues with colour accuracy for some reason.

 

 

Calibration Performance Comparisons

 

 

I've provided a comparison above of the S27B970D against some of the other screens we have tested. There are a lot of different calibration results achieved in the previous sections, both through software profiling in different preset modes, and through hardware calibration. For reference I have taken the software calibration results in the High Bright preset mode since this had produced the highest contrast ratio, and so was a more useful comparison perhaps of the screens optimum performance in that area in a moment.

 

Out of the box average dE was 2.6 which was pretty decent really and combined with the excellent default gamma and white point represented a good factory calibration. It offered a similar level of accuracy to the HP ZR2740w (2.2), Hazro HZ27WC (1.5) and DGM IPS-2701WPH (2.4) which also all had pretty good default gamma and white point setup. All these screens were ahead of some of the other 27" models like the AMVA based BenQ EW2730V (6.5) and the TN Film based Iiyama G2773HS (8.4) for instance.

 

 

 

 

The calibrated black depth and contrast ratio of the S27B970D varies depending on which mode you are operating in. We have provided the figures from the High Bright mode here (software calibration) since it had returned a calibrated contrast ratio of 800:1 which is the best you can get from the screen really. Software calibration in the standard preset modes left us with a more limited contrast ratio of 668:1, and in the sRGB mode the CR was crushed to 429:1 unfortunately. Carrying out hardware calibration in either the sRGB or the native colour space of the monitor allowed for a contrast ratio of ~420:1 when linear grey was the priority of the process, but up to ~640:1 when deep black was instead the priority. Overall the 800:1 figure obtained in the High Bright mode was pretty good and on par with many of the IPS screens we have tested. It was not as good as the VA based models however which can reach up to ~3000:1 in some cases.

 

 

Contrast Stability and Brightness

 

The luminance range of the screen was very pretty reasonable. At a maximum brightness setting (in the standard preset mode) the screen reached 248.9 cd/m² which was a little higher than the specified 220 cd/m² maximum in the standard mode. You may need to think about whether you would ever require a higher luminance than this (for movies or gaming perhaps) but I doubt many people would in real use. You can boost the maximum brightness to around 283 cd/m² if you use the High Bright preset as well. The luminance could be adjusted all the way down to a low 61.1 cd/m² through changes to the brightness control, giving you a 187.8 cd/m² adjustment range. This should afford you a good range of adjustments for varying lighting conditions. Those wanting to work in darker conditions should find the lower level adjustment fine, and a setting of around 30 - 35% should return you a luminance of around 120 d/m² out of the box. Black depth ranged from 0.35 to 0.09 cd/m² and the overall static contrast ratio was on average ~710:1 which was adequate, but not great. Again this could be improved to ~820:1 in the High Bright preset mode.

We have plotted the luminance trend on the graph above. The screen behaves as it should, with a reduction in the backlight intensity controlled by the reduction in the OSD brightness setting. This was pretty much a linear relationship.

Contrast stability was fairly stable across the range, but there did seem to be some slight instability at the lower adjustment end.

 

Dynamic Contrast

We tested the DCR feature as described above. When switching between an almost all-white and an almost all-black screen you could see the DCR kick in. The changes were smooth but very quick, taking about 1 second to alter the backlight between the two extremes. This controlled the backlight up to a maximum of 284.8 cd/m², which was the maximum luminance in the 'High Bright' preset. At the darker end, it controlled the black point down to 0.08 cd/m². This gave us a useable DCR of 3560:1 which wasn't bad, but not great. We tested the screen again with a completely 100% all-black screen and you could see that the backlight was being completely turned off. This would give you a DCR trending towards infinity:1, but really in practice you are never going to see a 100% black image and so it's use is irrelevant.

 

Viewing Angles

Above: Viewing angles shown from front and side, and  from above and below. Click for larger image

Viewing angles of the Samsung S27B970D are very good and very similar really to an IPS panel. Horizontally there are very wide fields of view with a small contrast shift only really becoming noticeable from a wide angle of about 45� and beyond. Vertically, the contrast shift was a little more pronounced but the fields of view were still good. As a result of the change in pixel structure from Samsung's PVA to their PLS technology the panel is free from the off-centre contrast shift which you see from VA matrices. This is one of the reasons why IPS technology is so highly regarded in the colour enthusiast and professional space since it can offer very wide viewing angles and freedom from this contrast shift. With PLS offering the same freedom it could well become a popular choice for colour critical work as well where wide viewing angles are important. The PLS panel is also free of the very noticeable contrast and colour tone shifts you see from TN Film panels vertically.

Above: View of an all black screen from the side. Click for larger version

On a black image, like many IPS panels, there is a white glow when viewed from an angle. This picture was taken in a darkened room though and in normal working conditions this shouldn't present much problem. There is no A-TW polarizer or equivalent film on this panel which was something rarely used in the IPS market, but was implemented on some older IPS screens to improve the off centre black viewing. Because of the size of the screen you may notice some of this glow from the corners when you are viewing it head on. This is only really noticeable in darkened room conditions and when viewing dark content and is quite similar to IPS panels.

Panel Uniformity

Measurements of the screens luminance were taken at 35 points across the panel on a pure white background. The measurements were taken using BasICColor's calibration software package, combined with the NEC customised X-rite i1 Display 2 colorimeter. The above uniformity diagram shows the difference, as a percentage, between the luminance recorded at each point on the screen, as compared with the reference point of a calibrated 120 cd/m². This is the desired level of luminance for an LCD screen in normal lighting conditions, and  the below shows the variance in the luminance across the screen compared with this point. It is worth noting that panel uniformity can vary from one screen to another, and can depend on manufacturing lines, screen transport and other local factors. This is only a guide of the uniformity of the sample screen we have for review.

Uniformity of Luminance (Standard Mode)

The luminance uniformity of the S27B970D was very good overall. There was some slight variance in luminance, mostly along the bottom edge where it dropped down to 104 cd/m² in the worst cases (-14% deviance). All in all though 97% of the screen was within 10% deviance of the centre of the screen, and 77% was actually within 5% deviance. A good result here from the S27B970D. This is the standard uniformity of our sample in all preset modes.

Uniformity Correction

 

As an additional feature available in the NCE software is an option to measure and correct variances in the brightness and colour across the screen within the 'calibration' preset mode. This is available through the 'uniformity' section as shown above. You can define the number of measurement points in your grid for this correction and you are then directed to place your calibrator on the screen and move it between each box as it tells you to. Obviously the more measurement points the better in terms of the results, but the longer it will take to complete.

 

 

The grid appears on the screen as shown above. The device then takes measurements at each point and corrections are made at a hardware level to ensure an even brightness and colour across the whole screen. The software makes two passes through each box. The first pass takes about 5 seconds per box and the second pass takes about 3 seconds. It's quite a long-winded process and a bit annoying as you have to keep re-positioning your calibrator across the screen.

 

 

 

Afterwards you are presented with a results screen which looks like the above. You are then asked if you want to load the NCU corrections into the monitor which takes about 8 seconds to complete. This is then saved to the hardware LUT and active when you are in the 'calibration' preset mode. As a result, this uniformity correction is only available if you are able to hardware calibrate the screen, so you must have the NCE software and a compatible calibration tool. You cannot take advantage of the uniformity corrections in any other preset mode either so in that sense it's a little more limited than other manufacturers techniques which are available in other modes (Eizo and NEC for example). However, it is a correction specific to your unit and based on real-life measurements you make so it should be reliable.
 

 

Uniformity of Luminance
(Calibration Mode with Uniformity Correction)

 

We took our same measurements of the luminance again across the screen and were pleased to see that the correction process through NCE had been successful. There was very little deviance at all now, with a maximum difference of only 5% in the bottom left and top right corners. The overall uniformity was excellent thanks to the corrections carried out. The good thing was that these corrections were specific to our sample panel, based on real-life measurements by the user. As such you can run this again over time to account for any backlight or panel variations which might arise. Combined with the hardware calibration you have a pretty powerful control over the internal LUT.

 

Backlight Leakage

Above: All black screen in a darkened room. Click for larger version

As usual we also tested the screen with an all black image and in a darkened room. A camera was used to capture the result. To the naked eye, there did not appear to be much in the way of backlight leakage although you could notice the characteristic PLS-glow as you looked at the black image from different angles. The camera picked out some slight unevenness and some clouding from the backlight in the right hand side corners. This was most apparent in the bottom right hand corner but in practice overall there was nothing too severe. There was no bleeding from the edges which was good to see as that can become quite distracting during some uses, for instance when watching a movie with black borders top and bottom.

General and Office Applications

The S27B970D features a massive 2560 x 1440 WQHD resolution which is only just a little bit less vertically than a 30" screen. The pixel pitch of 0.233mm is very small as a result, and by comparison a standard 16:10 format 24" model has a pixel pitch of 0.270mm and a 30" model has 0.250mm. These ultra-high res 27" models offer the tightest pixel pitch and therefore the smallest text as well. I don't find it too small personally, but day to day I am used to a 24" screen. Some users may find the small text a little too small to read comfortably, and I'd advise caution if you are coming from a 19" or 22" screen for instance where the pixel pitch and text are much larger. I found a 30" screen to be quite a change with text size when I first used one, and this is very similar and even a little bit smaller! I still personally prefer the slightly larger text of a 24" model myself, but I expect I could happily get used to the added resolution on these models given time.

The massive resolution is really good for office and general use, giving you a really big screen area to work with. It is a noticeable upgrade from a 24" 1920 x 1200 resolution, and it's good to see Samsung have opted for the high res panel here rather than reverting to a 1920 x 1200 or 1920 x 1080 res panel as you may find in other older 27" models. For those wanting a high resolution for CAD, design, photo work etc, this is a really good option. The image was very sharp and crisp and text was very clear. The glossy screen coating ensured that the white backgrounds of office documents looked clean and pure, and did not suffer from the grainy and dirty feel of some IPS panels featuring aggressive AG coating. Being glossy though it did introduce some reflections which were a bit of a pain sometimes. You will want to ensure you don't have the screen facing a window or strong light source I would think.

There were no specific presets for office or text work, but you could easily set up one of the others to your liking. We found default setup of the standard, high bright and sRGB to be very reliable in terms of gamma and white point which was great news. The sRGB emulation mode is also available if you specifically need to work with the slightly smaller colour space. Be warned though that the native preset mode does crush blacks and contrast ratio. The brightness control also allows you to control a decent range of adjustment to the luminance of the screen which is good. The out of the box default of 100% brightness is of course too bright for prolonged office use, so you will probably want to change this to about 30 - 35% to achieve a luminance of ~120 cd/m². Those wanting to use the screen in low lighting conditions shouldn't have any issue here either as the low level adjustment is good, offering a range down to about 61 cd/m². Another thing to note while we are talking about the brightness control is that the screen does not use Pulse-Width modulation (PWM) to control backlight dimming and so those who suffer from eye fatigue or headaches associated with flickering backlights need not worry here.

The stand provided offers a decent enough range of adjustments as well with a good height and tilt range available. There is no pivot mode for those who like to work in portrait mode. It should be noted as well that the screen cannot be wall or arm mounted. The integrated speakers should be adequate for general office sounds and light music as well and it's useful to see those included. It might have been good to feature an audio input as well to play sound from your PC through them, and perhaps a headphone socket. As it is, they only support sound when using the DisplayPort or HDMI inputs. There are also two USB 2.0 ports available which are handily positioned on the right hand edge of the base for quick access. There are no other features like card readers, ambient light sensors or human motion sensors here though. With DisplayPort and DL-DVI both supporting the full 2560 x 1440 resolution you should have a decent choice for your PC. Image quality was excellent with very crisp and clear text in office applications. There is no VGA connection available on this screen.
 

 
Above: photo of text at 2560 x 1440 (top) and 1920 x 1080 (bottom)

The screen is designed to run at its native resolution of 2560 x 1440 and at 60Hz refresh rate. If you want to you can run it outside of this and let the image be scaled to fill the screen. At the native resolution text was very sharp and clear. We ran the screen at 1920 x 1080 which was the next step down, while still maintaining the screens 16:9 aspect ratio. Text was actually good and was not blurred too much, although of course you do take a big hit in terms of resolution. To give you more desktop real estate and maximum picture quality, the native resolution is of course recommended where possible.

 

Responsiveness and Gaming

The S27B970D is rated by Samsung as having a 5ms G2G response time which implies the use of overdrive / response time compensation (RTC) technology, used to boost pixel transitions across grey to grey changes and improve responsiveness in practice and reduce ghosting and blurring. The panel being used is an Samsung LTM270DL02-201 PLS Panel and it is rated with a 12ms ISO response time for reference.

Before we get in to the side by side screen comparisons I want to quickly talk about the 'response time' (overdrive) control available through the screens OSD menu. It is available within the 'picture' section as shown above. This allows you to manually control the level of overdrive / RTC impulse being applied to the pixels, with options of normal, faster and fastest being available. You may wish to read our specs section for some further information about overdrive / response time compensation.

The screen was tested using the chase test in PixPerAn, a good bit of software for trying to quantify differences in real terms responsiveness between monitors. As a reminder, a series of pictures are taken on the highest shutter speed and compared. The images above are the best case examples from the screen with the 'response time' setting at each level. In the 'normal' mode the responsiveness of the panel is actually still pretty good. There is no obvious ghosting to the naked eye although a reasonable degree of motion blur is detectable. When switching to the 'faster' mode, this blur is reduced a fair bit and the moving image looks sharper and clearer. This setting is turning the overdrive impulse up of course and so pixel transitions are being sped up. This translates into a real life difference in perceived response times. We saw a very similar performance from the S27A850D when we tested it.

The 'fastest' setting turns the overdrive impulse up again another notch. However, in this mode it is turned up too high and is poorly controlled. As a result a noticeable white halo is introduced behind the moving car and a dark trail behind the moving speech bubble. Here the overdrive is causing the pixels to overshoot their required state and unfortunately introduce this distracting artefact. I wouldn't recommend using this setting unfortunately as the overshoot is quite pronounced and distracting during use. The 'faster' setting seems to offer the optimum performance in terms of fast pixel response times, and also freedom from any obvious overshoot, and I would recommend using that option. Again we had seen the same from the S27A850D and so it appears nothing has really been changed in terms of pixel response times or control thereof.
 

Display Comparisons

The screen was tested again using the chase test in PixPerAn for the display comparisons. As a reminder, a series of pictures are taken on the highest shutter speed and compared, with the best case example shown on the left, and worst case example on the right. This should only be used as a rough guide to comparative responsiveness but is handy for a direct comparison of the impact of this setting:

27" 5ms G2G Samsung PLS (Response Time = Faster)

27" 5ms G2G Samsung PLS (Response Time = Faster)

27" 6ms G2G LG.Display H-IPS

27" 6ms G2G LG.Display H-IPS

27" 6ms G2G LG.Display H-IPS

I have provided a comparison of the S27B970D first of all against some of the popular 27" IPS and PLS based screens we have tested. As a first comparison we have included the S27A850D model which was the first of its kind to feature a PLS panel. It had impressed us at the time with its decent responsiveness and the S27B970D was very comparable really. Both are provided here in their "faster" response time mode which is free from the overshoot artefacts you see if you push the setting all the way up to "fastest". The Samsung models are actually a little faster than the 3 IPS based screens shown here. The Hazro HZ27WC and DGM IPS-2701WPH are both glossy screens as well and although response times were good, there was a little more of a pronounced blur to the moving image. The Dell U2711 remains a popular 27" model and offered good responsiveness and low levels of blur. Unfortunately a dark overshoot was introduced which was pretty noticeable, and caused by a poorly controlled and too aggressive overdrive impulse. Overall the performance of the S27B970D was favourable here and another decent outing from PLS as a technology.

 

27" 5ms G2G Samsung PLS (Response Time = Faster)

27" 7ms G2G LG.Display p-IPS (response improve = on)

27" 6ms G2G LG.Display H-IPS (Overdrive = On)

I have also provided a comparison of the S27B970D against a couple of competing professional grade monitors. Given the price point and market position of the S27B970D it is likely that some buyers will want to compare with the high end NEC and Eizo models in the market. The S27B970D again performed comparatively very well. The NEC PA271W and Eizo SX2762W feature overdriven IPS panels. They did offer pretty low levels of motion blur and some decent performance really considering they are not gamer orientated screens, but there were some overshoot issues in some cases, particularly evident on the Eizo tests.

 

27" 5ms G2G Samsung PLS (Response Time = Faster)

27" 12ms G2G LG.Display H-IPS

27" 4ms G2G AU Optronics AMVA (AMA = Premium)

27" 6ms G2G AU Optronics AMVA (SmartResponse = Fastest)

27" 8ms G2G AU Optronics AMVA (AMA setting = Premium)

If you then compare the S27B970D with 4 other 27" screens we have tested which use AMVA or IPS panel technology there are more pronounced differences in some cases. The Philips 273E3QHSB and BenQ EW2730V are based on AMVA panel technology and fell behind in these tests. The generation of AMVA panel being used in those two models was not able to compete with the responsiveness of modern IPS or PLS displays and there were quite high levels of blur evident, even with their response time controls turned up to the optimum levels. Those screens are rated with a 6ms and 8ms G2G response time respectively which just goes to show you can't always trust a specification when determining real life performance of a display. The recently tested BenQ GW2750HM had offered some improvements, and along with the HP ZR2740w showed pretty low levels of blur. They were again not as fast as the S27B970D in practice though.

 

27" 5ms G2G Samsung PLS (Response Time = Faster)

24" 6ms G2G LG.Display e-IPS (Video OverDrive = On)

24" 8ms G2G LG.Display e-IPS

23" 8ms G2G LG.Display e-IPS (W-LED)

24" 4ms G2G AU Optronics AMVA (AMA = Premium)

Above is a comparison of the S27B970D against some popular models in smaller sizes. First are three models using IPS panels, but in smaller sizes of 24" and 23". The HP ZR2440w had performed very well in these tests and showed a similar level of motion blur to the S27B970D in practice. There was a very slight dark and pale halo trail evident in those tests but it was very slight. The Dell U2412M and U2312HM again offered low levels of motion blur but a more obvious dark overshoot trail was introduced. I have also included the results from our recent review of the BenQ GW2450HM since there had been some big improvements made in AMVA panel technology in this most recent generation of panel. Thankfully the responsiveness was much better than we'd seen from the Philips 273E3QHSB and BenQ EW2730V we showed you above and was on par in practice with these IPS screens.

27" 5ms G2G Samsung PLS (Response Time = Faster)

24" 2ms G2G AU Optronics TN Film + 120Hz (AMA = On)

27" 1ms G2G Chi Mei Innolux TN Film + 120Hz (Over Drive = 0)

22" 3ms G2G Samsung TN Film + 120Hz

I've also included a comparison above against three very fast 120Hz compatible screens we have tested. In all cases these other screens are using TN Film panels and are aimed primarily at gamers. Firstly there is a direct comparison against BenQ's XL2420T. This showed very low levels of motion blur, but some dark overshoot was introduced as a side-effect. The recently tested Iiyama G2773HS was very responsive and even has a quoted 1ms G2G response time. This showed very low levels of blur and had minimal issue with overshoot. The Samsung SM2233RZ performed very well in these tests and showed very low levels of motion blur. When 120Hz mode was enabled the overdrive artefacts evident in 60Hz mode were almost completely eliminated, which is something we have seen here with the BenQ XL2420T as well.

There is something else going on here though as well which can't be picked out by the camera. All of these TN Film models are running at 120Hz refresh rates, which allows for improved 120fps frame rates and the support of 3D stereoscopic content as well. This can really help improve smoothness and the overall gaming experience so these screens still have the edge when it comes to fast gaming. From a pixel response point of view the S27B970D performed very well, but there are some other areas you still need to think about when it comes to high end gaming. It couldn't keep up with the very fast TN Film models with 120Hz support.

The responsiveness of the S27B970D was pleasing and pretty much remained the same as the older S27A850D. It offered no obvious ghosting and only low levels of motion blur in the 'faster' response time mode. Unfortunately the 'fastest' setting was too aggressive and introduced some overshoot so I would recommend sticking with the 'faster' setting. The screen could compete easily with the popular  27" IPS models we had tested and showed a sharp moving image, free of any noticeable overshoot artefacts which had affected some of its competitors. The screen should be perfectly capable of handling fast paced games, although you may want to consider the type of graphics card required to run games with high settings at such a high resolution. Thankfully we'd also seen good image interpolation at lower resolutions and so gaming with an input resolution of 1920 x 1080 (for instance) is also very viable.

Additional Gaming Features

Above: aspect ratio options in PC mode. Below: Aspect ratio options in AV mode

Aspect Ratio Control - The screen offers several options within the OSD menu for hardware level aspect ratio control. There are actually different options available depending on whether you are in PC or AV mode in the OSD menu, and so you may have different options available depending on your connection option and the input device. In the PC mode there are options for Auto (maintaining the source aspect ratio whatever it is) and wide (fill the screen completely regardless of the source aspect ratio). In AV mode you instead have options to maintain 4:3 or 16:9 aspect ratios, or 'screen fit' which displays the input without truncating the original picture according to the manual.

Preset Modes - There is no specific game preset available from the screen so you will have to set up one of the other modes to your liking. This is probably only because its not really a screen aimed at gamers.

 

Input Lag

It is important to understand fully what input lag is and also the various measurement techniques which are used to evaluate this aspect of a display in the industry. As a result of our studies, we have improved our testing methodology by adopting the SMTT 2.0 tool which is used to generate the results below. Please see our full input lag testing article for all the details.

Input Lag Classification

To help in this section we will also introduce a broader classification system for these results to help categorise each screen as one of the following levels:

• Class 1) Less than 16ms / 1 frame lag - should be fine for gamers, even at high levels

• Class 2) A lag of 16 - 32ms / One to two frames - moderate lag but should be fine for many gamers. Caution advised for serious gaming and FPS

• Class 3) A lag of more than 32ms / more than 2 frames - Some noticeable lag in daily usage, not suitable for high end gaming

For the full reviews of the models compared here and the dates they were written (and when screens were approximately released to the market), please see our full reviews index.

Our tests here are based on the new format using SMTT 2.0. We have provided a comparison above against other models we have tested to give an indication between screens. However, please note that many of the other screens tested here were using older stopwatch methods and not the SMTT 2.0 tool. For reference, those shown as darker blue lines were tested using SMTT 2.0.

The Samsung S27B970D showed a pretty much identical input lag as its predecessor, the S27A850D (also tested at the time using SMTT 2.0). The average lag was 28ms, with a maximum of 31ms shown. Note that the input lag measurement here is based on the overall "display lag" as seen by the user, which would take into account raw signal processing delay + an element of the pixel response time for the relevant transitions. It should also be noted here that the input lag tests were conducted when in the "faster" response time setting as we had already identified that to be the optimum setting for gaming experience, being free from the overshoot issue when using the "fastest" setting. Of course the response time setting has an impact on the overall display lag of the screen in these tests. We conducted the same measurements when in the "fastest" setting for reference and the overall image lag was reduced a little to 24.4ms.

The lag of this screen has been categorised as CLASS 2 as detailed above and the lag is a little less than 2 frames. As such it may not be suitable for very high end gaming or fast first person shooters, but then again, this isn't really a gamer-orientated screen anyway.

 

Movies and Video

 The following summarises the screens performance in video applications:

• 27" screen size makes it a pretty good option for an all-in-one multimedia screen and comparable to smaller LCD TV's in size. A screen this big really does help lend itself to video viewing.

• 16:9 aspect ratio is more suited to videos than a 16:10 format screen, as it leaves smaller borders on DVD's and wide screen content.

• Native 2560 x 1440 resolution can easily support true 1080 HD content (1920 x 1080 resolution)

• Digital DL-DVI, DisplayPort and HDMI interfaces support HDCP for any encrypted and protected content

• Good to see DisplayPort and HDMI provided for connection of additional devices, both of which are very popular for external DVD and Blu-ray players

• Glossy screen coating can look attractive but may cause issues with reflections depending on room conditions and light sources. Perhaps not as suitable as an anti-glare coating for this purpose.

• Contrast ratio was ok in some modes, and High Bright mode did seem to return the optimum contrast ratio in practice. Darker detail should not be lost in movies

• Dynamic contrast ratio is available and works to a reasonable level in practice, up to around 3560:1. Might be useful for those who like the technology although transitions are very fast

• There is a 'Cinema' preset mode available in the OSD if you want to set up a mode specifically for your movie viewing

• Very good pixel responsiveness for movies and video which should be able to handle fast moving scenes without issue. I would recommend a response time setting of "faster" in the OSD menu

• Wide viewing angles thanks to PLS panel technology meaning several people could view the screen at once comfortable and from a whole host of different angles. The PLS glow from an angle might present a problem on darker content depending on your line or sight and distance from the screen

• Good ergonomic adjustments available from the stand with a good range of height and tilt available

• No obvious backlight leakage from the edges which is good. This type of leakage may prove an issue when watching movies where black borders are present but it is not a problem here. Some slight clouding in the right hand corners which might become evident in darkened room conditions sometimes.

• Integrated stereo speakers available if you want. Might be useful for the occasional video where needed

• There is no headphone socket provided unfortunately for private audio. There is also no audio input to connect sound from a PC into the integrated speakers

• No picture in picture (PiP) or picture by picture (PbP) modes available on this model.

• HDMI black level control via the OSD for optimising and controlling contrast from HDMI sources

• For PAL sources, we have tested the screen and confirmed it will support a resolution of 1920 x 1080 at 50Hz refresh rate, but not the native 2560 x 1440 resolution of the panel.

 

 

Conclusion

The Samsung S27B970D was a very enjoyable screen to test really, a whole range of new features and aspects to test from this relatively new panel technology. Our first impressions of the screen remain even after many hours of use, those being that it is one of the most attractive screens we have had the pleasure to test. The design is sleek and clean, the materials of a very high standard and the glossy coating really gives it a premium feel. The thin profile and tidy appearance from behind also help with the overall aesthetics of the screen. Samsung have provided some other nice features for a model in this price bracket, including integrated stereo speakers, touch sensitive OSD controls, a good range of ergonomic adjustment options and a good range of interface connections.

From a performance point of view we were impressed by the default setup of the screen and factory calibration, and the gamma and white point settings were very reliable. There was a useable sRGB emulation mode as well which was good, but did unfortunately crush the contrast ratio which was one drawback. Calibration results were excellent from software profiling and we'd achieved a decent contrast ratio in the High Bright preset as well. Hardware calibration was relatively easy although support for colorimeters was limited and reporting functionality was brief. We achieved good results when calibrating to the monitors native gamut, but when using sRGB we could not achieve correct colours for some reason - although contrast ratio was thankfully improved over the screens native sRGB emulation preset. This hardware calibration was not as thorough as we would have perhaps have liked. We were pleased also with the lack of PWM for backlight dimming and the uniformity of the panels brightness. The uniformity correction feature was also successful and a nice extra feature. Pixel response times were also very good although for very high end gaming the input lag might be a little too high.

Samsung have gone a different route with the S27B970D than many other professional grade screens from the likes of NEC and Eizo. They have stuck with a standard gamut backlight for a start and a standard 8-bit panel. This might be more suited to many users but you do need to realise it won't offer wide gamut or "10-bit" support like some competing models. The move to a standard gamut backlight through the use of a W-LED unit does mean the screen offers a much thinner and sleeker design than the often very bulky and heavy pro-grade models we've seen before. The glossy screen coating is also an interesting choice. It does help with the overall appearance of the screen and you certainly get sharper and cleaner picture quality compared with the grainy appearance of some IPS AG panels. It's not to everyone's taste though and you do need to be mindful of reflections and finger prints.

The S27B970D is very new and so not available widely yet. In the UK it retails for �799.99 (inc VAT) which makes it a little cheaper than some competing IPS based models, like the NEC PA271W (~�910) and Eizo SX2762W (~�950) for example. You do miss out on a few features as already mentioned but as a high end screen its a very interesting choice. Of course with the added extras and premium features it is more expensive than popular mainstream models like the Dell U2711 for instance (~�550) and certainly a lot more than low end 27" IPS models like the DGM IPS-2701WPH (�380) and Hazro HZ27WC (�420). However, if you're looking for something more, and want something with a lot of style and some great all round performance then the Samsung S27B970D is definitely worth looking at. Another pleasing outing from PLS technology.