Original Link: https://www.anandtech.com/show/10243/qd-vision-color-iq-and-the-philips-276e6-review



At this year's CES Josh and I sat down with representatives of QD Vision to discuss their quantum dot display technology, along with where they see the television and monitor market moving in the next few years. QD Vision offers a quantum dot solution for displays, which is branded as Color IQ. The interesting proposition that QD Vision brings to the table with their technology is that it's not just usable in high end displays, but also in less expensive ones where it can be used to bring features that were traditionally limited to high end displays down to a lower price point.

After our meeting with QD Vision, we were informed that Philips would be launching a new line of monitors that use QD Vision's Color IQ technology. Given that these are some of the first computer monitors to come to market with quantum dot technology, I was quite interested in taking a look at it. The monitor in question is the Philips 276E6 monitor, which has a 27" panel and claims to cover 99% of the Adobe RGB color gamut. The full specifications of the Philips 276E6 can be found in the chart below.

Philips 276E6
Video Inputs VGA, DVI-D, HDMI
Panel Type IPS-ADS
Pixel Pitch 0.311 mm
Colors 16.7 million (8-bit)
Gamut 99% Adobe RGB
Brightness 300 cd/m2
Contrast Ratio 1000:1
Response Time 5ms GtG
Viewable Size 27-inch
Resolution 1920 x 1080 @ 60Hz
Viewing Angle 178°/178°
Backlight W-LED + QD
Screen Treatment Anti-Glare
Tilt -5° to +20°
Dimensions 640 x 471 x 235  mm
Weight 5.33 kg
Accessories VGA Cable
Power adapter

Before moving forward, there are obviously a few points to address about the Philips 276E6. The first is the resolution and pixel density. At 27", a 1920x1080 resolution is definitely on the lowest end of the spectrum. It's very important to keep in mind that the 276E6 retails for only $300, which really isn't enough to get you a 27" 2560x1440 sRGB monitor unless you can order from Korea and dodge import fees. With that in mind, you're certainly not going to find a 2560x1440 Adobe RGB monitor for $300, and with the purpose of monitors like the 276E6 being to drive down the price of wide gamut displays, this concession makes sense. However, it is true that the pixel density of a 27" 1080p monitor is quite low, and having used a 2560x1440 27" monitor for several years now it did take some adjustment to get used to.

One other point to consider regarding the 276E6 is that, as a wide gamut monitor, it's positioning itself as a product for photographers and other professionals who would like to be able to work in a wider color space. For those applications the relatively low resolution poses less of a problem than applications that involve looking at a great deal of text. The Philips 276E6 is also just the first of many displays that will come to market with this technology, and even for users who are interested in a smaller or higher resolution panel the 276E6 will provide insight into the level of quality that can be expected from this new generation of inexpensive wide gamut displays.

As for the design of the Philips 276E6, I think it's quite unique, but I'm not sure if I'm a huge fan of it. The chassis is definitely on the flimsy side, and the fact that it's made of white glossy plastic doesn't help the visual impression that it's not the sturdiest monitor. The panel has an AG coating, but it's not as heavy as the coatings I've seen on monitors that are really heavily targeted at office use. 

The back of the monitor is the same plastic as the front, although the chassis isn't a single component, so there is a gap between the two parts that runs around the edge. The back has a wave-like pattern, which I think looks sort of odd, but it's not really a problem since it's on the back of the monitor where it probably won't ever be seen. All the ports are back-facing rather than down-facing, and they include a port for the power adapter, a VGA port, a DVI-D port, and an HDMI port. There's also a jack for HDMI audio out.

As for the stand, it looks like a fairly study metal stand. However, that's only really true for half of it. The base of the stand is metal, and is removable, but the shaft is made of plastic and is permanently attached to the display. The stand has a degree of tilt, although tilting it too far worries me because the stand can be quite wobbly and I worry that any sudden shift or an impact on the desk may topple it. 

One other thing I wanted to comment on is the OSD and the buttons for accessing it. To be quite frank, the buttons are horrible. The response is inconsistent, and you often end up hitting the wrong button by mistake and closing the menu. I wish manufacturers would just use physical buttons, as they're much easier to use and I really doubt that the impact on the bill of materials is significant. 

For $300 you're not going to get an aluminum enclosure for your monitor, and in fact you don't really get that even for $1000 unless you buy Apple's Thunderbolt Display. However, I think darker matte plastic would have probably been a better option, and it should have been possible at this price point. Getting a stand with height adjustments and rotation is going to require buying a more expensive monitor, and the tilt range is as much as you'll need for a monitor of this size. Ultimately a monitor is going to be more about function than form, and that's what we'll get to next.



Color IQ

As I mentioned earlier, the technology at the heart of the Philips 276E6 monitor is QD Vision's Color IQ quantum dot technology. To gain a better understanding of how this differs from other quantum dot implementations currently used in the market, I spoke with QD Vision's Chief Marketing Officer John Volkmann.

Quantum dots are a type of semiconducting nanocrystal. They're typically made of cadmium selenide or indium phosphide, and when used in displays they have a diameter less than ten nanometers. What makes them interesting is that they exhibit a property known as photoluminescence, which means that they emit light after absorbing photons.

In LCD displays this property is highly desirable, as it means that you're able to place an array of quantum dots between the backlight and the color filters to reduce the frequency of the light emitted by the blue backlighting. By altering the diameter of the quantum dots you can control the frequency and wavelength of the light that is emitted, which allows for the emission of specific red, blue, and green wavelengths at the required intensity to cover your target color gamut. Smaller quantum dots on the scale of one or two nanometers emit wavelengths of light in the blue part of the visible spectrum, while larger quantum dots with a diameter of six or seven nanometers emit red light.

A question you may have is why this is actually necessary. I mentioned above that quantum dots are typically used to convert blue light into red and green light, and the use of blue LEDs for backlighting is not unique to quantum dot displays. Almost all modern LCD displays use LED backlighting, and the majority of them use what is commonly referred to as WLED backlighting. In truth, these "white" LEDs are really blue LEDs paired with a yellow phosphor, and through this process wavelengths of blue, green, and red light are produced. Unfortunately, there is still a very significant blue bias in the final output, and the intensity of the desired red and green wavelengths is relatively low. Because of this, these displays are limited in the range of green and red colors they can reproduce, and to date most monitors of this type have been limited to roughly 99% of the sRGB color gamut.

To produce a wider color gamut with LED backlights alone, vendors have employed the use of different technologies. The most prominent is GB-r backlighting, which pairs green and blue LEDs with a red phosphor to allow for green and red light of a greater intensity. Unfortunately, such designs have shown to be quite expensive, and this has kept wide gamut displays priced well outside what is affordable for the average consumer. An even smaller group of displays has employed full RGB backlighting, but due to cost this did not see much adoption by any display vendor.

The cost-related issues of RGB and GB-r backlighting is the problem that QD Vision hopes to solve with their Color IQ technology. Color IQ's appeal is that it works with standard edge-lit displays, and it takes advantage of the blue LED backlighting that those displays employ. Most quantum dot technologies require the use of expensive full-array backlighting because they use a thin film layer with quantum dots embedded throughout it which sits between the backlighting array and the color filter layer. In contrast, Color IQ uses small glass cylinders that sit in front of the blue LEDs at the edge of the display. According to QD Vision, the cost of a film-based solution for a display around the size of a 50" television can cost around $100, while their quantum dot solution for edge-lit displays will only cost around $20.

With QD Vision's current technology the cylinders with quantum dots sit between the blue LEDs and the light guide plate that distributes the light across the panel. With such an implementation one can expect displays that closely cover the Adobe RGB and DCI-P3 color gamuts depending on exactly how the quantum dots are tuned. According to QD Vision, quantum dot technologies perform best when the quantum dot array is as close to the backlight as possible. Within the next few years they hope to be able to deliver a "chiplet" solution, which consists of a quantum dot matrix mounted in a bead of glass right atop the LEDs. Moving beyond that will be integrating the quantum dot matrix right into the LEDs themselves. Right now such solutions are infeasible due to heat degradation, but they will be necessary as we move toward full coverage of the Rec. 2020 color gamut.



Contrast, Brightness, and Gamut

Of course, while QD Vision's Color IQ technology looks good on paper, what's equally important is how well the technology translates to the real world. QD Vision's goal to bring down the cost of backlighting suitable for wide gamut displays is unabashedly aggressive, and like other efforts to reduce manufacturing costs, cost reductions need to be carefully balanced to exploit the advantages of new technology without unnecessarily sacrificing quality. To that end QD Vision's first outing in the PC display market is an especially interesting one, as we can see and evaluate first-hand the true gamut capabilities of Color IQ as implemented in Phillips' 276E6 monitor.

Starting things off with a look at some more basic monitor metrics, Philips rates the 276E6 as having a peak brightness of 300 nits and a contrast ratio of 1000:1. This is in line with what you'll typically find on displays of this price, and in general you probably won't be using a monitor at anything close to 300 nits in a typical workspace. As always, measurements for white and black level are done with an i1DisplayPro due to its greater accuracy with levels below 0.2 nits than the i1Pro 2.

White Level -  i1DisplayPro

Peak luminance on the Philips 276E6 is relatively high. While we have seen some monitors reach beyond 400 nits, in practice this isn't really important because the ambient environment lighting for a monitor is usually constant, and rarely requires a brightness above 100-200 nits to overcome reflections. As for the minimum brightness, in its standard Adobe RGB mode the display dropped to 77 nits. This is actually fairly bright, and if were any brighter it would be difficult to perform our 80 nit calibration later in the review.

Black Level - i1DisplayPro

Black levels on the Philips 276E6 are quite good as well. At maximum brightness it's one of the better panels on record, which will pair well with its high brightness. At minimum brightness the gap between it and the next best display is quite a bit larger, but it's important to remember that the Philips 276E6 has a minimum brightness that is also higher than most displays, and so the contrast ratio should end up being quite good in both cases.

Contrast Ratio -  i1DisplayPro

As far as contrast ratio goes, the Philips 276E6 does as well as you'd expect based on its white and black levels. Obviously there are now displays on the market that utilize photoalignment technology to achieve contrast ratios around 1800:1, but 1000:1 is quite a good result for a $300 display, and it's right in line with what Philips advertises so you're definitely getting what you paid for.


Philips 276E6 gamut DeltaE with default settings

 


Philips 276E6 gamut DeltaE with OSD tweaks

Gamut accuracy on the Philips 276E6 can vary pretty wildly. On both of the units I tested there were two common errors. The first is color, with the blue primary being undersaturated while the red primary is significantly oversaturated. The second problem is the white point. If your luminance is wrong your colors will also be wrong, and on both monitors it took a lot of fiddling with the OSD to get an accurate white point, and you can see the result of that in the photos above. Out of the box the white error on our second unit causes the DeltaE to approach four.

Generally, you'll be able to eyeball it and figure out which of the white presets is the most neutral, but even if you do you're also dealing with significant errors in blue, red, and the secondary colors that rely on them. Considering that the Color IQ tech is supposed to be highly tunable I really don't know how such large errors could exist in the shipping product, and it's not clear whether this is a technology limitation or a decision on Philips' part. In any case it doesn't look good to have large errors on the most basic of our tests.



Adobe RGB: Pre-Calibration Testing

Our first tests involve measuring the Philips 276E6 prior to any calibration being performed. These are arguably the most relevant numbers for this sort of monitor, as it's highly unlikely that consumers purchasing $300 monitors will also happen to have a colorimeter or spectrophotometer laying around to calibrate it. 

While no calibration is performed before this test, the display is set to a brightness level of 200 nits to keep results comparable between reviews. The white point setting has been left in the default Adobe RGB mode, which for some reason happened to be more accurate than the mode explicitly labeled 6500K.

Greyscale

On this unit, greyscale accuracy was where I would expect a low priced wide gamut monitor to be. What's strange is that the gamma was closer to a target of 2.6 despite the fact that I left the monitor in its default power 2.2 gamma mode. It's worth noting that the original unit had a gamma that was much closer to 2.2, but the RGB balance for grey shades was much more red shifted and so the greyscale DeltaE was actually higher than this unit. It looks like there's a fairly large degree of variance between different units of the 276E6.

Saturation Sweep

Due to the shifted primaries and improper gamma, the Philips 276E6 doesn't perform as well as it could in our saturation sweep test. Magenta is pulled toward red, while cyan is pulled toward green. For many levels of saturation there are fairly severe errors in magenta and blue, and even more so in green, red, and cyan.

Gretag-Macbeth ColorChecker

In the Gretag-Macbeth ColorChecker test the Philips 276E6 doesn't perform very well. The average DeltaE is nearly five, with a number of colors actually exhibiting individual errors above six. In this case the oversaturated red primary is causing significant problems with accuracy by also shifting shades of yellow, orange, and magenta toward red. I really have no idea why Philips decided to tune the monitor in this manner, and unfortunately it makes the monitor not very useful for work that depends heavily on color accuracy.

Adobe RGB: 200 Nits Calibration

Our 200 nit calibration target is still the Adobe RGB gamut with a power 2.2 gamma. Since we can't actually alter the display's primaries due to there being no 3D LUT, there will be no way to improve upon the errors with the color gamut and any saturations or color mixtures that rely heavily on accuracy there.

While my earlier testing was done in the monitor's default Adobe RGB mode, for calibration I moved to using the user defined mode which allows control over the white point through a set of RGB sliders. This allowed improvements to be made at the monitor level before making further tweaks by performing the greyscale calibration, which helps to retain tonal range as there are fewer adjustments that need to be made in the GPU's LUT.

Greyscale

Greyscale accuracy on the Philips 276E6 improves dramatically after calibation. While the gamma is still far too high in the darkest shades, it's much more linear and now tracks fairly close to our 2.2 target rather than 2.6. The greyscale does have a number of areas where one shade will have a much higher error than the surrounding ones, and it may take moving from a 65 point to an even more comprehensive 255-point calibration to eliminate these errors.

Saturation Sweep

The average error with primary and secondary color saturations is lower after calibrating the 276E6, but there's a caveat. Due to adjustments made to the greyscale, as well as the adjustments made to the monitor directly through the white point settings before calibration, the error in cyan and green is actually much higher in the lower saturations, while the errors for blue, red, and magenta in the more intense saturations are also higher. I'm honestly hesitant to actually describe this as an improvement, and many of the errors are far too severe for the monitor to be usable in color critical applications.

Gretag-Macbeth ColorChecker

Performance in the Gretag-Macbeth ColorChecker test improves after calibration, but much of this is due to the improvement in greyscale accuracy, with many colors still exhibiting very large errors. Unfortunately, even after calibration, the Philips 276E6 isn't really suitable for use as a monitor for photo or video editing.

Adobe RGB: 80 Nits Calibration

For our 80 nit calibration we continue to target the Adobe RGB gamut, but in addition to the lower brightness we also target the sRGB gamma curve rather than a simple 2.2 power function. sRGB's gamma allows for greater detail in the darkest regions of images, and this calibration target closely reflects what one would target on a professional display where images are being edited for print.

Greyscale

As expected, the 276E6 struggles when calibrated using the sRGB gamma target. In the darkest shades of grey the errors are quite high, descending from a DeltaE value of roughly 9 at black to an error of 3 at roughly 25%. Beyond that point the calibration is actually fairly good, and the average overall error is below our target value of 3.0. However, the severe inaccuracy in the dark regions makes it fairly evident that the monitor won't be usable in applications that require strict conformance to the sRGB gamma and luminance specifications.

Saturation Sweep

Surprisingly, the Philips 276E6 performs much better in the saturation sweep with our 80 nit calibration than it does at 200 nits. This may be due to the modifications I have made at the monitor level to correct the white point before doing a greyscale calibration in CalMAN, and given that the white point settings on my two samples were very different it's likely that results with different calibration targets will vary a great deal from unit to unit.

Gretag-Macbeth ColorChecker

Another surprise is the fairly low average error in the ColorChecker test. I can really only ascribe these differences to the changes made when altering the monitor's white point, but it really is interesting to see a display perform better with this arguably more difficult calibration target than with the 200 nit calibration with a simple power 2.2 gamma. 



Display Uniformity

While measurements taken at the center of the display are one thing, the accuracy of images across the entire panel is another. Even if you have a display that is accurate in the center, large errors relative to that may mean that the display actually doesn't show a very accurate image overall. This can cause significant problems with video and photo editing, as it's necessary to use most of your display when doing those tasks to see as much of the image as possible. To examine uniformity, I've used our standard white, black, contrast, and color uniformity tests, which are all based on the patterns from the Gretag-Macbeth ColorChecker test.

White Uniformity

White uniformity is definitely not bad on the Philips 276E6, especially by the standards of $300 monitors. However, it's pretty apparent when using it that the left side of the display is significantly dimmer than the center. Depending on what sort of work you do this may or may not pose a problem, but for color-critical work the brightness variance is probably going to be too high.

Black Uniformity

Black uniformity is a bit all over the place. If you divide the display into two sections along its right diagonal you find that the top section is darker than the center area, while the bottom section is much brighter. This is again fairly visible when using the monitor.

Contrast Uniformity

Contrast uniformity is really just a function of the white and black uniformity. In this case there's an area of lower contrast along the bottom of the display, with the rest of the display actually being fairly good aside from a couple areas along the very top. It's just unfortunate that there's so much backlight bleed at the bottom of the panel, as that's really what's causing the issues here.

Color Uniformity

Color uniformity on the 276E6 suffers from the same issues as the brightness uniformity. This is to be expected, as if your luminance level is incorrect your colors will also be incorrect. Even when doing simple things like browsing the web you can tell that the left side of the display is not as uniform as the area right around the center, and it's quite unfortunate because as far as uniformity goes it's only the bottom left part of the panel that really hurts the 276E6's usability as a display for image and video editing.



Color Management

Readers may be wondering why I didn't run the Philips 276E6 through our sRGB test bench. The story behind that is a long one, and to tell it I need to first go over some aspects of how color management works, and how the 276E6 exposes a number of problems with color management on current computers.

Color management isn't discussed very often. In my view, there are three reasons behind this. The first is the fact that most consumers have been using displays that don't even meet the sRGB gamut for many years now, and so there wasn't much need to discuss color management in a display-related context. The second is the fact that Windows computer manufacturers have only really started bothering to calibrate their displays within the last two years or so, and prior to that time color management almost didn't matter because you were getting a severely inaccurate sub-sRGB display that wouldn't show anything accurately regardless of what gamut content was made for. The third reason is simply that color management should just work, and it should be invisible to the user. In some contexts, this is true, such as how an operating system manages color conversions between RGB and CMYK when printing. When it comes to displays, the issue can be much more complicated.

Before moving ahead it's important to make sure that the basics regarding color management are clear to anyone who hasn't encountered it before. Put simply, color management is the process of transforming image data between different standards for displaying color. As I mentioned above, an application of this that many people encounter every day without knowing it is the transformation of an image from an additive RGB color space, to a subtractive CMYK color space which printers use. Essentially every operating system handles this without issue, but the same cannot be said about managing different color standards for displays.

For the purposes of this article it's sufficient to just consider sRGB and Adobe RGB. sRGB is the current standard for all images and graphics displayed on the web, while Adobe RGB is a color space developed by Adobe which extends the green primary of the sRGB color space. Both of these standards define various characteristics about how color should be displayed, including the color gamut, gamma function, white point, luminance, and black level. The Adobe RGB gamut is significantly larger than the sRGB gamut in its reproduction of green and cyan shades, which is why monitors that support it are referred to as wide gamut displays.

Having a display with a different color gamut than that of the one used on the web can pose significant problems. It's up to the operating system, its frameworks and APIs, and the apps built on top of them to properly handle the mapping of content made for the sRGB color space to the monitor's wider color space. To help with this, displays should provide an ICC profile, which is a file that describes information about the monitor's color characteristics. With a proper ICC profile, the system's color management framework will know the specifics of the monitor's gamut, along with the gamma ramps to be loaded into the GPU's lookup table to provide corrections. It's worth going over the process of applying these in Windows and OS X.

Windows makes the task of setting an ICC profile quite confusing for the average user. To do so, one has to open the Windows Color Management settings, which is still part of the legacy control panel rather than being integrated into the new Settings application that has existed since Windows 8 launched. In the case of the Philips 276E6, you'd expect that you could simply select the default monitor profile, click "Use my display settings", and you'd have every application managing color properly.

Unfortunately, the process I described above won't change anything about your display's output. For starters, simply checking that box doesn't actually do anything regardless of what profile you've selected, despite the fact that it explicitly says the box enables the settings you've chosen. For whatever reason, you then need to click on the advanced tab, and then click on the button to change the system defaults. From there, you're then brought to what appears to be the screen you began on, but in this case you're managing the default settings for the system which will apply to all users. From here, you should check the box that enables the use of Windows display calibration, which will actually enable the settings you changed in the first window.

On OS X, the process involves going to the color tab of the display settings page and clicking on the profile you want to use. This instantly sets the profile across the OS. I tend to lean toward the OS X implementation as being the simpler one, as clicking on one thing is simpler than having to navigate a number of menus, toggle checkboxes with inaccurate descriptions, and eventually resort to finding a guide on Google such as this one to figure out how to load an ICC profile properly. In my experience the color management at the OS level in Windows is notoriously unreliable as well, with Direct3D applications being able to load whatever they want into the GPU's LUT if they run fullscreen, and the ICC's LUT often not loading again even after exiting, which requires trying to force it to load by toggling it on and off or just rebooting the entire computer.

Fortunately, there are a number of third party applications to handle the loading of ICC profiles on Windows, which have mainly been created to address the problems with the built in functionality. Users who profile their display with CalMAN will likely opt for SpectraCal's CalMAN Client 3 to manage profiles, and there are many free programs like Color Sustainer and CPKeeper which work reliably and often can reload on a timed basis which allows settings to be properly restored after being overwritten by the bad behavior of most game developers.



Constraining To sRGB

Every monitor and television has an internal lookup table, which is independent of the LUT used by the GPU in the connected device. This is essentially a stored list of calculations that define what output value should be displayed on the monitor for a given input value from a computer or set top box. This may or may not be user accessible, and high end monitors will have a high precision internal lookup table which is really more like a 3D cube that can be used to adjust intermediate points of gradation where colors are blended instead of simply adjusting three individual tables for each primary color. While that is beyond the scope of this article, the concept of a monitor's LUT is important to the topic of monitor display modes. Wide gamut monitors almost always have an sRGB display mode which constrains the display to the sRGB gamut, and this is accomplished at the level of the display's LUT with no connection to the OS or to a GPU's LUT. 

With the previous section discussing how ICC profiles are used to make the OS and its applications aware of a monitor's native color space, you may be wondering what the point of offering a narrower gamut display mode is. Before moving on, I need to cover one other point about color management.

The function that performs the transforms between different color spaces is called the color management module, or CMM for short. If one wants to think of color management as a stack or a chain, you have color descriptions in ICC profiles on top, with the CMM sitting in the middle, and your color management API on the bottom for programs to access. When content that is not made in the display's native color space is encountered, the color management module first looks at the data provided about the content's color characteristics. It then transforms these values into an intermediate color space based on the CIE 1931 color space, which encompasses all colors that can be seen by the human eye. This is called the profile connection space, or the PCS. From the PCS, the values are then mapped into the target color space of the display, and in theory this should provide an "accurate" representation.

In the case of moving from a smaller gamut to one that is a superset of it, the content should look identical to a reference display for the content's native color space, as the larger gamut is perfectly capable of showing all the colors that exist in the smaller one, with those colors simply being defined by different coordinates. When moving from a larger gamut to a smaller one there needs to be a decision made about how to represent colors that can't even be shown in the target space. Typically, the solution has been to scale all colors appropriately to maintain the relative difference between colors, which means that the image is technically less saturated in areas where it could have been rendered natively, which is a tradeoff to properly maintain gradations within an image.

Unfortunately, the fact of the matter is that not all applications will play nice with OS level color management, particularly on Windows. In these situations, the system's color management module is never invoked, and no color management occurs at all. The typical result is that content is presented as though it was native to the monitor's color space, resulting in significant oversaturation and a completely inaccurate image. Because Windows is the most widely used operating system for computers, monitor manufacturers have gotten around the deficiencies of the system's color management by simply allowing users to use an sRGB mode that constrains the display's gamut at the level of the monitor LUT. This means that you lose any benefits of the wide gamut mode, but because most content is sRGB there's typically no difference, and when you do need to use a wide gamut for photo editing or other work you can toggle it back on temporarily.

The included sRGB option does not alter the output in any manner

On the Philips 276E6, there is unfortunately no hardware-based solution to the color management problem provided. The issue is that there is no working sRGB display mode. In fact, the original unit I received had no sRGB mode at all, which I found quite surprising. After emailing QD Vision who then communicated with Philips, I was shipped a replacement unit that was apparently from a later production run where an sRGB mode was added. Upon setting it up I was delighted to see that there was an sRGB toggle in the settings menu, but this quickly faded as I realized that the setting did absolutely nothing, and I confirmed that by measuring the display in both the Adobe RGB mode and the sRGB mode.

To not have an sRGB mode is one problem, but to have the option and have it not even do anything is arguably much worse, as it's like advertising a feature that doesn't work rather than not offering it. With no way to constrain the gamut at the hardware level, the only solution is to use ICC profile and rely on applications being color managed. At this point another problem crops up, which is that the Philips 276E6 doesn't provide an ICC profile that properly characterizes its output, and so there's no way for applications to properly display images even if they do support color management.

To fix the situation somewhat, you need to go back to the Windows Color Management settings, ensure that you've enabled calibration using the confusing steps that I described earlier, and finally set your device profile to the Adobe RGB (1998) profile in the drop down menu. If that profile isn't there by default, it's readily available on the internet and can be installed after downloading by right clicking and installing from the context menu.

Technically it's improper to use the standard Adobe RGB profile as the device profile, as the monitor is not perfectly matched to the Adobe RGB spec which is pretty clear based on our measurement results from earlier. However, it's the best solution there is when a proper ICC isn't provided, apart from using a $1500 spectrophotometer to make your own ICC which defeats the entire point of the 276E6's low price. It's worth noting that in my case I've set the device profile to Adobe RGB system wide, because I've been testing the Philips 276E6 on its own. For users with multiple displays this should be set for each display individually in the original settings screen depending on what gamut each one supports. At this point applications that support color management will render images more correctly, but applications being properly color managed is not a given.

At both the OS level and the application level, there are programs that just don't play nice with color management. Above you can see an example of how the new Windows Photos app actually isn't displaying an image correctly, while the very old Windows Photo Viewer actually does, with Photoshop also there as a reference application that is known to support color management. One thing to note is that if you grab the images I've used off the web they'll actually look more like the improperly managed applications in these screenshots. This is due to the color transformations that I described earlier, with me explicitly choosing to target the sRGB color space in these screenshots grabbed from an Adobe RGB display, which reduces the saturation of colors to maintain gradations. I think the surrounding discussion makes it fairly obvious why I'm not relying on the proper rendition of Adobe RGB tagged images to demonstrate this, and since the relative difference between colors is maintained it doesn't have any impact on the comparison.

These issues extend to other parts of Windows as well, including areas such as the wallpaper. When the core image applications of an operating system aren't managing color properly, especially such basic things like the desktop wallpaper, it's difficult to imagine that third party software is either.

Probably the best example I can find of an application that is only somewhat color managed is Google Chrome. Web browsers in general have had a lot of problems with color management. Microsoft Edge, which is Microsoft's brand new browser, doesn't support it at all. Firefox requires configuration modifications to work with anything beyond tagged images. In the case of Chrome, there is support for displaying images with embedded ICC profiles. Unfortunately, this really doesn't go far enough to address all possible cases, and this is a recurring problem that I've found. While being able to properly display images that are tagged is a good thing, many programs will simply assume that an image was made for the target device's color space if they are not tagged at all. You can see the problems this causes in the image above, with an image grabbed right from the internet displaying incorrectly in Chrome because it has no embedded sRGB profile. In my experience this is often the case, as you usually need to use a program like Photoshop and explicitly include an ICC profile to have a tagged image.

In almost all cases, the assumption that content is designed with the target device's color characteristics in mind is an incorrect assumption to make, as all content made for the web targets the sRGB standard. Safari is, to my knowledge, the only major web browser that adopts this behavior and assumes that untagged images are sRGB. The same is true for the display of CSS colors. Although they are explicitly defined as being in the sRGB color space by the CSS color specification, with no profile information it's the job of the web browser to do the work there, and most simply don't bother. As a result, you don't see a website as the designer intended it to be, and the colors can be quite straining to look at in some cases. AnandTech itself is a good example, with some of the blue text being much more difficult to read when the saturation is ramped up, and the orange highlights becoming particularly gaudy looking.

In the end there's just too much unreliability on Windows within the operating system, Microsoft's own apps, and third party apps to simply rely on the color management system to make sure everything displays correctly. Windows is by far the most used operating system for consumer desktop computers and laptops, and Philips really should have included a proper sRGB mode on the 276E6 so users would be able to see most content properly, with Adobe RGB being available when working in applications that actually require and support it. While the core issue is something that Microsoft seriously needs to address, right now the solution is for monitor manufacturers to fill in the gaps, and companies that are entering this space using QD Vision's technology really need to make note of this.



Final Words

QD Vision's Color IQ tech certainly delivers. In the case of the Philips 276E6, it actually delivers more than what it promises. Technically the monitor doesn't meet the Adobe RGB spec, but this is mostly due to it exceeding it rather than falling short. The gamut that it achieves is clear evidence that this quantum dot technology can be employed in monitors with relatively low prices to achieve a wide color gamut, which is something that has only existed on a small group of premium monitors until now. Given that the Philips 276E6 shows oversaturation with its red primary, I would be interested in seeing Color IQ used in a monitor targeting the DCI-P3 color space which is about to become the canon color space for UltraHD content as we move away from sRGB on a path toward eventual Rec. 2020 support.

While the Philips 276E6 is certainly a successful demonstration of QD Vision's quantum dot technology, it's difficult to say that it's successful as a product in its own right. This is a combination of two factors, with one of them being primarily an external factor.

From the last two pages it's pretty clear that Windows is not ready at all for a transition to a world beyond sRGB, and even within that gamut it makes it quite a pain to do basic color corrections. For many years, vendors who ship wide gamut displays have identified this issue and provided a fix of sorts in the form of an sRGB monitor mode which constrains its gamut so the vast majority of content on the web will render correctly without relying on proper color management. With Philips being a new entrant to this space, it seems that they were either not aware of, or underestimated the necessity of such a feature. I want to stress that this isn't something that any of these vendors should have to do, but when the most widely used desktop operating system doesn't do a good job with color management, it's something you need to do to provide a good experience for your users. Philips hasn't helped this problem by also not even providing a proper ICC color profile so that applications that actually are color managed will work correctly.

The second factor is that the Philips 276E6 is just not where it needs to be in terms of uniformity and color accuracy. Based on my measurements of two of these monitors, it's clear that Philips is allowing a large degree of variance between units. Out of the box, it's hard to tell what settings provide the most accurate image. On my original unit it was the Adobe RGB preset, while on the second unit it's the 6500K preset. Regardless of which I chose, both monitors exhibited concerning issues with color accuracy, and both had an oversaturated red primary. I'm not the only reviewer to find this, and so it's probably true of all the units which is very disappointing. 

Post-calibration numbers were better in some respects, but not others. The big shift in saturation accuracy with the 200 nit calibration was very surprising to me, and it may be best to not tweak the white point at the monitor level at all. Unfortunately, making more corrections through greyscale calibration means you reduce the tonal range of the monitor further by limiting the number of distinct levels for the red, green, and blue components, which can introduce color banding. On top of that, the fact that the Philips 276E6 is trying to target a low price point means that the idea of calibrating with a $1500 spectrophotometer using $3000 software is quite absurd, and the very large variance between panels means there's not even any point in me providing an ICC profile to be used in a general manner.

In the end, I think Philips simply has some things to learn about the wide gamut monitor market, and I'm still quite interested in seeing what future products they release, along with what future products will come from other manufacturers. Philips should definitely be applauded for taking the first step toward low-cost wide gamut displays, and if they can improve their panel accuracy and include a proper sRGB color mode they'll have a very compelling product on their hands. If 1920x1080 is the target resolution to manage cost I would probably opt for a smaller panel size as well, as the pixel density is just too low on a 27" panel.

On the software side, the companies that currently ship operating systems with essentially non-functioning color management need to get their act together. Wide gamut displays are coming, and not handling multiple color standards properly is incredibly detrimental to the user experience.

As for Color IQ, I think the technology has a bright future. It's clear that it can be added to displays with only a minimal impact on price to the consumer, and the advantages are significant. The tech can clearly push a wider red primary than the Adobe RGB standard specifies, so I'd like to see some DCI-P3 monitors using the tech so consumers can take advantage of upcoming UltraHD content that will support the wider color space. As a technology, I think Color IQ will probably exist alongside film-based quantum dot technologies, as edge-lit LCDs are never going to properly support HDR standards because of their inability to do proper local dimming, and a film solution is the only feasible way to use the tech in smartphones and tablets. However, with the majority of the  TV and monitor market using edge-lit displays there's a huge opportunity here to bring wider color gamuts to the masses. While I cannot really recommend buying the Philips 276E6 in its current state, I'm looking forward to future products that use QD Vision's Color IQ technology, both from Philips and from other vendors that I anticipate will adopt this technology soon.

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