It's been a long time coming, but NEC have finally decided to release their popular LCD2490WUXi monitor in Europe and the UK! We spoke about this news back in January, and NEC have kindly sent us  a review unit now it has been officially launched. The screen has been popular in the USA, where it was the first mainstream model in this size to feature an IPS based panel. The UK saw the launch of rival IPS models such as the Hazro HZ24W in late 2007, and more recently the launch of models such as the HP LP2475W around September 08.

The NEC LCD2490WUXi has been well recieved in the United States, where it became the only real option for those wanting an IPS based screen at 24 inches, and particularly aimed at colour critical work. The larger 26" LCD2690WUXi had already been established across the world as an impressive colour enthusiast screen, but the US market had little to offer in the smaller sizes really. The popularity of the NEC LCD20WGX2 (again IPS based) helped establish a decent following of it's 24" brother. It is presumably due to demand that the 2490WUXi has therefore reached our shores, and I am pleased to have the opportunity to review the screen thoroughly.

The NEC 2490WUXi forms part of their colour orientated screens, and there are several features designed to make this a more premium model than many popular screens. Features such as 12-bit Look Up Table (LUT), AmbiBright and ColorComp will be discussed later, as will the fact that this screen uses an A-TW polarizer and an H-IPS based panel from LG.Display. Before we get into all the details and tests, let's take a look at the spec:

 

NEC's product pages state: "Watch your productivity soar when you go wide with NEC. The 24� (24.1� VIS) NEC MultiSync LCD2490WUXi delivers an entirely new perspective to your desktop. With its wide-format design (16:10 aspect ratio), which provides roughly the same work area as two smaller sized displays, you can simultaneously view multiple/side-by-side application windows. With its multitude of leading-edge capabilities, combined with groundbreaking design, this monitor could easily be considered the most intelligent visual display solution to date."

Above: Various views of the screen, including rotated into portrait mode

The 2490WUXi features a decent range of ergonomic adjustments, including a large height adjustment of up to 150mm. There is also a pivot, rotate and tilt option from the versatile stand. The practical use of the rotate function on a screen this size is debatable I'd say, but is nice to see included anyway. Tilt, height and pivot adjustments are all very useful, and I'm glad to see them included. The movement of the adjustments are smooth and easy to manoeuvre, but I did feel that the stand was a little unsturdy. It tends to rock around and wobble when you are moving the screen, and even if you have any knocks on the desk for instance. It is a well built piece of kit, but I felt the stand and overall feel was a little 'wobbly'.

The materials are all of a high quality and build quality is good, save for the stand which we have discussed above. The unit is very quiet, although there is a very faint buzz if you press your ear up to the sides, but certainly nothing you can really hear in day to day use or from anywhere further away. The screen gives off minimal heat, especially once brightness is turned down from the default 100% (discussed later). The screen uses 83W of power when active, but drops down to 1W only when in standby. There are various power saving options including 'Eco Mode' and a timing schedule, which are all available to explore through the advanced OSD menu.

Above: OSD operational buttons as well as ambient light sensor (far left) and blue operational LED

Above: OSD operational buttons. Click for larger version

The 2490WUXi has a thin bezel around all of the panel, being about 2cm thick on all sides. In the bottom right hand corner there are discreet buttons for operating the OSD (or OSM - On Screen Menu, as the manual refers to it). These feature a left/right and up/down directional buttons to help make navigating easy, as well as a couple of unmarked buttons which feature as 'menu' and 'reset' on the most part. The ambient light sensor is situated to the left of the power LED, which in itself is fairly subtle. This glows a bright blue colour normally (not as overbearing as the image above might suggest) when the screen is operational, but can also be turned to green if you so desire via the advanced OSD (more on this in a second). This also glows orange when in standby mode.

There is quick access to input selection via the 'input' button (obviously), while the left/right control gives one-touch access to brightness, and the up/down control to contrast.

Above: OSD options shown when buttons are pressed


Above: Regular OSD options shown including RGB section and standard brightness/contrast controls

Upon pressing any of the OSD buttons, a little menu pops up in the corner of the screen as shown above, which tells you what each button will do. The OSD is pretty easy to navigate and there's plenty of options to choose from. There is also even an 'advanced menu' mode which you can access should you so wish. If you hold the 'input' button down while you turn the screen on, this wil activate or deactivate the advanced menu when you next press the 'menu' function button. Within the advanced menu there is a whole host of other options to choose from.

Above: advanced menu sections 1 and 7

The advanced menu looks like the above. I've not taken screen shots of every section as there's too much to go through, but I did want to touch on a few of the more interesting features and options. As you can see from menu section 1 (left hand image above), the control for brightness has changed from being a percentage to being a luminance value. It should be noted that these figures don't quite correspond to a real value in terms of luminance, and we will cover this a little more in our contrast stability section. The value shown here of 137 cd/m² corresponds to a percentage setting of 24.9%. In reality this is nearer to 200 cd/m² when measured by the colorimeter.

Menu section 7 also features a couple of extra things you won't find in the regular OSD. 'Overdrive' is available here with an option of on and off, something we will test later on. You can also control the level of the ColorComp feature and even change the LED colour between blue and green.

 
Above: advanced menu sections 9 and C

Section 9 offers some further features as you can see above, including the option to turn DDC/CI on or off. This will become handy later on when we calibrate the screen. Section C also offers a pretty comprehensive power schedule so you can control when the screen is on and off, presumably pretty handy for public displays. There's plenty of features in the advanced menu, but I won't go through them all! If you read the manual which is available online, it tells you more about all these options and what they do.

Above: Interface options. Click for larger version

At the rear of the screen on the underside are the connections for DVI-D, DVI-I and VGA / D-sub. These are discretely tucked out of the way and easy to access, and there is a useful cable tie on the rear of the stand. The 2490WUXi also supports NEC's TileMatrix and TileComp technologies, which allow you to build virtually seam�less video walls of various configurations (horizontal or vertical) through the Advanced OSD

 

Colour Accuracy, Black Depth and Contrast

The NEC LCD2490WUXi utilises an 8-bit H-IPS panel, capable of producing a true 16.7 million colours. The screen also features a 12-bit LUT (Look Up Table) offering a total palette of 69 billion colours, in theory helping to eliminate colour banding and posterization effects. Unlike many modern displays, the screen uses standard CCFL backlighting and so it's colour gamut covers 72% of the NTSC colour space (76% Adobe RGB is also advertised by NEC), a moderate figure compared with many modern W-CCFL and LED backlit screens with extended gamuts.

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 set it to its standard profile. The 2490WUXi was tested at default factory settings using the DVI interface, and analysed using LaCie's Blue Eye Pro colorimeter and their accompanying software suite.

Default settings of the screen were as follows:

NEC LCD2490WUXi - Default Factory Settings

The default settings of the screen left it feeling over-bright, something not uncommon in the displays we have tested to date. Again it seems shipping the monitor with 100% brightness setting is the preferred option, so if nothing else, you are going to want to turn that down considerably. We look at the contrast stability of the screen, along with luminance readings at different brightness settings later on in the review, but at default settings it was just too high. The colorimeter revealed a luminance of 380 cd/m², only slightly off the specified maximum brightness of 400 cd/m². With this high default luminance, black depth was recorded at a moderate 0.45 cd/m², giving a pretty reasonable contrast ratio, especially for an IPS based panel. It should be noted that the IPS panel being used here (LG.Display LM240WU2) is older than that in the HP LP2475W (LG.Display LM240WU4) which performed very well in this regard. Not a bad performance at all for an IPS panel!

Default gamma was recorded at 2.1, only marginally off (4%) from the target of 2.2; that being the default for computer monitors and for the Windows operating system and sRGB colour space. Colour temperature accuracy was fairly average at 5757k, being a little way off from the 6500k target (the temperature of daylight). These results at factory settings were pleasing at least, and so if you at least lower the brightness control, you should have a reasonable starting point for some calibration.

The CIE diagram on the left hand side confirms that the screen uses standard CCFL backlighting, and so it's gamut covers about 72% of the NTSC colour space, and is very close to the reference sRGB colour space shown by the black triangle. The gamut offered here is low by todays standards really, where W-CCFL and LED backlighting commonly offer anywhere from 92 to 135% of the NTSC colour space. However, I will not penalise the 2490WUXi for offering a more 'traditional' gamut, since it is not all about numbers and specs here! There are pros and cons to a wide gamut display, and it is largely dependent on what type of content you are using and what type of colour result you are looking for. In fact many buyers have chosen the 2490WUXi because it is only standard gamut, selecting it over newer models such as the HP LP2475W for this very reason. There are a mixture of opinions on the wide gamut debate, but all you need to know about with this display is that it is a standard gamut screen. I would thoroughly recommend a read of this article over at X-bit Labs, which covers the pros and cons well.

 

Testing with the colorimeter revealed the graph on the right hand side above, showing DeltaE (dE 94) values across 16 shades. As a reminder, the lower these bars down the Y-axis, the better, in terms of colour accuracy. For reference, LaCie describe the DeltaE readings as:

At default settings, colour accuracy was fairly good on average, with a dE of 2.3. This actually offered pretty accurate colour reproduction even at factory settings, and this was a pleasing result from the 2490WUXi. The screen is orientated at the colour enthusiast market, and so accurate colours, even without calibration, are certainly advantageous. dE maximum ranged up to 8.7 in blue shades, so you will need some form of calibration to improve on these results.
 

The OSD offers a range of preset modes within the 'RGB' menu. These range from settings 1 - 5, which in turn range in colour temperature from 5000k to 9300k. There is also an 'sRGB' preset which was listed with a 6500k colour temperature in the OSD. We selected this sRGB preset to see if it offered any more accurate settings than the default 'native' mode. All other settings were left at default for now, and the results of our testing were as follows:

NEC LCD2490WUXi - sRGB Preset Mode

This preset made little difference to the overall accuracy of the screen, as compared with our target settings. Gamma remains at 2.1, colour temperature improved slightly towards the 6500k target, but only by 1%. The reading here of 5840k was still a way off the desired level, and indicates that the preset wasn't as close to the 6500k as the OSD would suggest. Luminance was improved (reduced) slightly to 357 cd/m², but black depth remains unchanged at 0.45 cd/m². As a result static contrast ratio was a little lower, this time at 793:1. The colour accuracy was also not quite as good, with an average dE of 2.7 now instead of 2.3. Maximum dE was still in blue shades at 8.6 (rather than 8.7 before). Not really much point in changing to this mode to be honest, you will still need to calibrate for better results from the 2490WUXi.

 

Calibration

The 2490WUXi offers something a little different to most screens we test. This model features hardware calibration, allowing you to change the settings at a monitor LUT level. This has the advantage of storing the settings and profile in the monitor itself, which is more reliable and effective when it comes to profiling and maintaining colour accuracy. Below you will see several different results including tests we did with NEC's own latest SpectraView II (v1.1.00) software.
 

Stage 1: Initial Calibration Process - LaCie Blue Eye Pro Software

We carried out our calibration process as we would normally in our reviews, working from a starting point of default settings (as tested above), and following the guided process in the LaCie sofware. During the calibration process there was no prompts to manually select brightness, contrast, RGB values etc from the OSD as there would be normally, and instead the whole process is automated. Upon loading the LaCie Blue Eye sofware and clicking 'calibrate', the software says "connecting monitor" which causes the screens brightness to flash and vary. This stage sets up the communication between the software / colorimeter and the hardware LUT, via the DDC/CI communication. This is all without the need for any additional cables, and  is done over the DVI cable and interface.

This automated process continues, and the software then tells you it is "updating monitor" and flashes through several different colour temperature modes ranging from the very blue, to very yellow then begins to optimize grey balance and other settings in a more familiar way. The process takes longer than the usual automated process we are used to from LaCie's software, in total lasting around 10 minutes.

The calibration was clearly a great success! The screen felt more comfortable to use, and luminance was key to this of course. The colours felt even and testing with horizontal and vertical gradients showed no signs of colour banding. Gamma, colour temperature and luminance were all corrected nicely. Average dE was now a very respectable 0.4, with a maximum of only 0.9. LaCie would consider colour fidelity to be excellent now. You will notice the black depth and contrast ratio are poor here though, and we will discuss this in a moment.

Even in the other areas there was still some room for improvement though...
 

Stage 2: LaCie Blue Eye Pro software with LUT Profiling

We actually went into the advanced settings of LaCie's software to select a LUT profile rather than a matrix profile (which is the default), and tested whether this would offer improved results over the above. This resulted in the following (again OSD settings remained unchanged):

Colour accuracy was improved even more, with a dE average of only 0.2, better than the avearage of 0.4 from the matrix profiling. Maximum dE was also only 0.5 now as compared with 0.9 before. This was the best result we have seen from a calibrated screen in all of our tests, beating the previous champion the HP LP2475W, which offered a default dE of 0.3 and maximum of 0.5.

Again, you will notice that black depth and contrast ratio are poor here, even after calibration and we have an explanation for this. Since the calibration process with LaCie's software is automated, it offers you no prompts to alter the OSD settings for brightness and contrast. As a result, the brightness setting remains at it's default factory maximum of 100%. At this setting, the intensity of the backlight lamps are at their highest, and so even though the calibration as altered luminance by changing the LUT's, the backlight is still blaring out at 100% intensity behind the panel! This results in a poor black depth and contrast ratio.

 

Stage 3: LaCie Blue Eye Pro software Without Hardware Calibration

It's an odd thing, but it seems if you allow the LaCie software to automatically communicate with the monitors hardware LUT, it doesn't seem to think that an adjustment of the brightness control in the OSD is necessary. As a result, you are left with an overly intense backlight, and a poor black depth. There is a way round this while still using LaCie's software, but you have to resort to doing so without hardware calibration.

Firstly you need to stop the software communicating with the monitor automatically. Since this is done via the DVI cable, and using the DDC/CI communication method, you need to turn this feature off. While this option is not available in the standard OSD, it is available in the advanced OSD which we discussed earlier. As a reminder, hold the 'input' button down while turning the monitor on, and you are then given access to the advanced version of the menu. Turning the DDC/CI function to 'off' means you can calibrate the screen in the more traditional way, at a graphics card LUT level.

During this process you are given full access to the brightness and contrast controls as normal. We adjusted the brightness setting to 137 cd/m², which equates to 24.9% in the normal OSD. Contrast and black depth were both left at 50%. We also changed the RGB values to 184, 251, 229 respectively, something which you again have access to via the advanced OSD menu.

As you can see, the main thing we were looking to fix here was the black depth, which is now a far more respectable 0.20 cd/m², giving us a static contrast ratio of 600:1. Gamma, luminance and colour temperature remain spot on, and although colour accuracy isn't quite as good as hardware LUT alteration, it still results in an average dE of only 0.4, and a maximum of 0.8. Still very impressive.

Stage 4: SpectraView II Calibration

NEC actually offer their own calibration software for use with some of their range, and this is the SpectraView II package. I'll give a trimmed overview of the software, before going into some tests to see how well it can calibrate the screen, and if it can do any better than LaCie's software. NEC's documentation states:

"The SpectraView system uses a color sensor to take color measurements of the display screen during calibration. The software analyzes these measurements and sends color adjustment commands directly to the display monitor. This means that color adjustments are made in the monitor rather than in the video graphics adapter, resulting in full use of the number of colors available on the graphics adapter and a much brighter image with the maximum possible color gamut. With SpectraView, the video graphics adapter is not used at all to make any gamma or Tone Response Curve corrections to the display, so the full color resolution and fidelity of the system is maintained."

After installing and loading the software, it automatically detects your connected NEC display, and your connected colorimeter. There is an indication (as shown above) of your target calibration settings, which are based on the preset modes which is selected as 'photo editing' here. There are also options including broadcast video, DICOM Blue, DICOM Clear, Digital Camera and Print Standard. Each has it's own preset values for white point (colour temperature), gamma and intensity (luminance). The software confirms the screen is currently uncalibrated.

Entering the 'preferences' menu provides access to select your colorimeter along with some more advanced options. These include the option to choose the number of 'calibration and profile steps', with the higher number of steps taking more time, but potentially producing the best results. While 32 steps it supposedly "sufficient for most applications", we have choosen 52 for highest quality results. There are also choices as to whether the calibration priority should be to achieve the best contrast ratio possible or the best grayscale colour tracking. The details of these options are shown in the screenshot above and we will test both here.

There are options to generate an ICC profile after calibration and whether the software should then automatically associate this profile with the Colour Management System (CMS).

The target sub-menu allows you to manually select the target levels for colour temperature, luminance, black level and gamma should the preset modes not suit. For the purposes of this review, we are working towards the 120 cd/m² as recommended for LCD screens.

We proceeded with the calibration process which is again entirely autmomated. The software goes through several stages including optimizing white point (colour temperature), intensity and black level, all the while giving you a nice indication of progress and on-the-fly readings as shown above. It cycles through several colours and in total takes around 10 minutes to complete. At the end you are prompted to name and save the ICC profile, presuming you have selected these options in the preferences menu.

At the end you are presented with an 'Information' page as shown above, giving you the readings for white point and so on that you have now reached. You will note that here the black depth has reached a respectable level of 0.19 cd/m², and checking the OSD shows that the software has been able to alter the 'brightness' control (and therefore backlight intensity) to 24.9%. Contrast and black depth remain at 50% in the OSD. This improved black depth leaves us with a fairly respectable contrast ratio of 618:1, not bad from an IPS based panel, especially as it's a year or two old now. This figure actually doesn't quite add up when you look at the 120 and 0.19 cd/m² values shown for luminance and black level above. This should be more like 632:1, but perhaps there's some rounding of the values somewhere which is skewing it? Contrast ratio is good for an IPS panel, but can't quite keep up with modern S-PVA and TN Film panels.

The gamut tab gives you a visual representation of the screen's colour space using a CIE diagram as we are used to. Nothing staggering here, but again showing the monitor covers pretty much the sRGB colour space.

The gamma curves tab compares the target and calibrated gamma curves, showing again that calibration was very successful here.

The colour tracking tab gives you a view of deltaE values, albeit in a less 'friendly' way than LaCie's software. The SpectraView II analysis suggests we have reached an opimum calibration of dE 0.5 (average) and dE 0.72 (maximum). There is a section for DICOM conformance, but we won't go into detail there.

The SpectraView II software now confirms we have calibrated the screen as shown above.

I tested the new calibrated settings using LaCie's software to see what it thought of the results, and this is shown above. LaCie actually reckon that the calibration has given us a dE average of 0.3, whereas the SpectraView II software thought it was more like 0.5. Maximum dE was 1.3 here though whereas SV II thought it was  0.72. Regardless, this is still evidence of a good calibration, and we at least have a decent luminance and black level compromise which the LaCie software couldn't attain when left to hardware calibration. The calibration doesn't seem to be quite as good as the LUT-profile process of LaCie's software, but is pretty close. The accuracy in darker tones and greys let the overall result down slightly.

It's interesting to note that while LaCie's automated process did not seem to adjust the monitors 'brightness' control, the SpectraView II software did so nicely. With the former, although this had given us excellent results in terms of colour accuracy etc, the 100% backlight intensity left us with a poor black depth of 0.59 cd/m², and a poor contrast ratio of 203:1 as a result. NEC's software at least automatically controls the backlight intensity, and brought the setting for brightness down to 24.9%. This resulted in a much better black depth of 0.19 cd/m², and a contrast ratio of 632:1.

I repteated the SpectraView II process again, this time choosing grey-scale optimization from the preferences menu to see if that offered anything different and whether it helped improve the grey tone accuracy. It did help improve the accuracy there, but other colour tones were adversely affected and the overall accuracy was actually a little worse than before, where optimized contrast ratio was selected.

All the ICC profiles produced during our calibration process are available in our ICC Database. If you have software which is capable of communicating with the hardware LUT, these will even activate the profile at that level for you.

 

Calibration Summary and Comparisons

We've tested the 2490WUXi quite thoroughly here, but have determined a few things. Hardware monitor LUT calibration offers the most accurate results in terms of colour accuracy which is not surprising really. This was the best results we have seen from any of our reviews, offering an average dE as low as 0.3, and a maximum of only 0.5. However, the LaCie software was responsible for bringing us the best results in terms of accuracy, but had trouble producing a decent black depth and contrast ratio. It seems it deemed it unnecessary to change the OSD setting for brightness to anything below 100%, resulting in an overly intense backlight and washed out blacks. Calibrating without hardware LUT alteration still produced good results, but gave us access to change the backlight intensity and give a decent black depth and contrast ratio.

The NEC SpectraView II software was capable of altering the backlight through the brightness control and produced some good results at a monitor LUT level. This was pleasing and it's a nice piece of software. Calibrating at a monitor level as opposed to graphics card level should in theory mean the screen can retain better settings when using extenal devices, other PC's etc, and the calibration remains stored in the hardware itself offering better longer term results.

NEC also advertise this screen as featuring X-Light Pro technology, designed to maintain a consistent light output from the backlight unit (BLU) for the useful life of the display, as well as correcting for short-term fluctuations. This should in theory help in the long term to keep the display performing as it does when it's new.

We have plotted the results of the NEC 2490WUXi here against some of the other 22" - 26" monitors we have tested. As you can see, the 2490WUXi offered very good default accuracy of colours when compared with some of the other models, and once calibrated, it was the best we have seen.

Calibrated black depth was also pretty good, being on par with the AMVA based NEC 24WMGX3 (0.19) and certainly better than some other IPS based screens such as the Hazro HZ24W (0.38) and HZ26Wi (0.58). The more recent HP LP2475W still offers a slightly better black depth than the 2490WUXi, with a very impressive 0.17 after calibration. Top place goes to the S-PVA based HP LP2275W, with a black depth of 0.14; showing that S-PVA is very strong in this regard.

All the ICC profiles produced during our calibration process are available in our ICC Database. If you have software which is capable of communicating with the hardware LUT, these will even activate the profile at that level for you.

 

Contrast Stability

The brightness control in the OSD allows you to control the level of the backlight intensity, in turn allowing you to control the luminance of the display. The default setting for the screen is 100%, which actually gives you a luminance of around 374 cd/m², clearly far too high for any continued use. Thankfully the brightness control affords you a fair range of luminance, allowing you to reach down to a level of around 158 cd/m² at 0% setting. The 'Low Bright Mode' feature in the advanced OSD allows further reduction, in theory up to another 50 cd/m² through digital white level control. This is still not ideal however, and so you're going to need some degree of calibration to reach the recommended 120 cd/m² setting for LCD screens in normal lighting conditions.

Black depth also varies nicely as you lower the brightness control, ranging from 0.45 cd/m² at 100%, down to 0.19 cd/m². This is a respectable performance, especially when you consider this is an IPS matrix, and one which has been around for a couple of years in fact! Throughout this test, contrast remained very even, with a contrast ratio of around 830:1 being available.

Plotting these results on the above graph shows that the 2490WUXi offers very good contrast stability, with the backlight control having very little impact on the screens ability to maintain a decent ratio to black.

 

Viewing Angles

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

The NEC 2490WUXi features an H-IPS panel which offers the widest viewing angles of the main panel technologies in the market. NEC even state that this screen uses their "XtraView+" technology, which they say is why viewing angles are so wide. In reality, it's down to panel technology, and IPS has long been regarded as having the widest viewing angles, and is also free from the off-centre contrast shift you can detect from VA matrices. This is the reason why many colour enthusiasts consider IPS to be the only choice for colour work, as the VA contrast shift anomaly can be quite distracting in practice. Viewing angles of the 2490WUXi were very good in all directions, but you could spot a shift in the contrast as you moved past about 50� horizontally, and past about 30� vertically.

This screen also features an Advanced True-Wide polarizer, which helps maintain a deeper black from wide angles of view. This is something which has featured on a few models, including the larger brother of this model, the 26-inch LCD2690WUXi. This A-TW polarizer has the effect of improving black depth from an angle, but does add a slight white tint to the image when you look at it from a fairly wide angle. This replaces the common purple tint you can see from IPS panels without this A-TW polarizer.

 

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 LaCie Blue Eye Pro 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.

ColorComp = On

The 2490WUXi features an advanced feature to supposedly help improve panel uniformity. ColorComp reduces uniformity imperfections by compensating for differences in colour and luminance across the screen area, claims NEC's documentation. By default, this feature is turned 'on' in the OSD, and in the advanced menu you can even control its level from 1 - 5. We have left this setting on 3 which is the default. I tested the screens uniformity first of all with this feature left on. Panel uniformity overall was not too bad, but the bottom half of the screen, particularly towards the bottom left hand corner, was darker than the top. Luminance ranged down to 99 cd/m² in the very bottom left corner, being quite a way off from the target of 120 cd/m². Towards the top edge of the screen the luminance was recorded up to around 127 cd/m².

ColorComp = Off

I turned the ColorComp setting to 'off' to see what difference this technology was making to uniformity. No other settings were altered. It's hard to know what to think here really. Overall the screen was a little brighter than when ColorComp was turned on, and so the minimum luminance was now only 106 cd/m² in the bottom left. However, maximum luminance was now 136 cd/m². The pattern of uniformity seems to be very similar here really as it was when ColorComp was on. The reason for the higher brightness now was only because we had carried out our calibration process while ColorComp was on, and so the tests there were nearer to the 120 cd/m² we had aimed for. It's hard to tell if this technology really makes any difference in practice, but there at least doesn't seem to be any harm in having it turned on. Results may vary from one unit to another, but with our sample, it didn't seem to make a lot of difference.

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

As usual, I tested the screen in a darkened room, showing an all black background. The above image was captured by my camera. There was very little noticeable light leakage from any of the edges or corners, and black uniformity was very good overall. There was only a very slight leakage towards the very bottom left hand corner, but nothing obvious at all.

 

Office and Windows Use

The 2490WUXi is primarily aimed at colour enthusiasts, and so use with office applications is bound to be important. The 1920 x 1200 resolution gives you a large resolution for applications, and is suitable for some nice side by side split screen office work. You can comfortably have two Word documents side by side on a resolution this size which is very useful I find.

The 0.270mm pixel pitch is a nice intermediate level I find (personally), between the slightly small 0.258mm of 20"WS and the slightly too big 0.282mm of 22"WS models. I tested the screen in clone mode which showed that the DVI interface was a little sharper and clearer than the D-sub VGA connection. The 2490WUXi offers excellent picture quality with no text blur or issues that I could detect. There are even two DVI interfaces on this model for connecting 2 PC's or devices digitally.

You will definitely need to calibrate the screen, or at least lower the brightness setting massively, in order to use this model for any prolonged period of time. The default luminance is far too high for comfortable use, but thankfully calibration is easy and effective. The ColorComp feature, which we have discussed already in the uniformity section, doesn't seem to offer much, but is there as a feature to help maintain an even backlight intensity. This could be useful to some (if you find it helps) for office work.

Within the advanced OSD is the settings for auto luminance and auto brightness. The auto luminance feature stabilizes the luminance and colour of the image when the brightness setting is adjusted. Option 1 stabilizes luminance, 2 stabilizes colour, and 3 stabilizes both. Turning the feature to 'off' reveals the auto brightness (AmbiBright) control, which works well. Level 1 activates the auto brightness sensor which is situated just next to the power button. This automatically regulates the backlight intensity (brightness setting) on the fly, depending on your ambient lighting conditions. I like this feature, and it's a nice thing to see included in my opinion. Selecting '2' activates auto adjustment based on the content of the image on the screen. When setting 2 is selected, the AmbiBright sensor itself is not functional and so doesn't respond to ambient light conditions. All in all, this is a very decent screen for office use.

 

Responsiveness and Gaming

The NEC 2490WUXi 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 below show the best case example on the left hand side, and the worst case example on the right hand side. This should only be used as a rough guide to comparative responsiveness but is handy as a way of keeping a constant test of each screen.

8ms G2G LG.Display H-IPS

8ms G2G LG.Display H-IPS


6ms G2G LG.Display H-IPS


6ms G2G AU Optronics AMVA

6ms G2G Samsung S-PVA

The 2490WUXi uses response time compensation (RTC) to boost the pixel response times across grey transitions. The panel is made by LG.Display, who have rated the panel with both a traditional ISO response time (black > white > black transition) of 16ms, and a G2G figure of 8ms. This signifies the use of RTC technologies, commonly also referred to as overdrive.

The above tests show a few interesting things. Firstly, the H-IPS panel being used here is the LM240WU2 from LG.Display. This is also used in the Hazro HZ24W which we tested quite a while ago. You will see from the PixPerAn images that both these models are very similar in performance really. The Hazro shows a slightly paler trail in the best case scenario pictures, signifying that the RTC impulse is not quite as well controlled as on the NEC. Poorly implemented RTC impulses can cause an element of 'overshoot', where the overdriving voltage causes the pixels to go a little too far before they reach their desired orientation, resulting in a white halo behind moving objects. This can also affect pixels by leaving a darkened or even black trail behind moving objects, something which was 'famously' evident in the Dell 2407WFP-HC. Here, the 2490WUXi shows less of a white halo than the Hazro which is a positive sign.

If you compare the screen to the more modern panel (LM240WU4) used in the HP LP2475W you also see a few slight differences. The panel used in HP's model is a newer generation from LG.Display, featuring an extended colour gamut and a slightly improved response time of 6ms G2G. The above images show that the trail behind the moving car on the LP2475W is less pronounced, showing an improved response time which could warrant the descrease of 2ms on the spec sheet. However, the trailing images on the HP are of a darker tone, again signifying a slight overshoot of the RTC impulse, and some inverse "overdrive trailing". This is nowhere near as obvious as on the Dell 2407WFP-HC we mentioned earlier, but you can spot it if you look closely. The NEC 2490WUXi doesn't show this dark trailing, again suggesting the RTC impulse is well controlled.

The NEC 24WMGX3 and Dell 2408WFP are also shown here for reference, and are a little behind the 2490WUXi in terms of pixel responsiveness. The 2490WUXi's responsiveness was very good I felt, offering no obvious ghosting or trailing, and a seemingly well controlled RTC impulse to boot. This was one of the better 24" screens in fact when it comes to pixel responsiveness, which is quite surprising when you consider this is really a colour enthusiasts screen. In gaming there was still noticeable blurring in fast moving scenes, but you should expect this from LCD displays anyway.
 

I also wanted to see what the 'overdrive' function did in the advanced OSD. It is clear from the first set of images that the screen is already using RTC to boost response times anyway, and the 'overdrive' option is set to 'off' as default. Moving the setting to 'on' must increase the RTC impulse for an even more aggressive overdrive, and the PixPerAn shots above suggest this is the case as well. If you watch the moving car in the test and flick between overdrive being on and off, you can easily spot the difference even to the naked eye. The feature doesn't appear to do much, if anything, for the actual responsiveness of the moving image, and blurring is no less apparent. What the feature does do is introduce a rather obvious pale halo behind the moving car, showing that the RTC impulse is perhaps too much now, and is causing some quite noticeable overshoot. I can't see any reason to use this option in the menu to be honest, it is probably something NEC were toying with during production, but decided to settle at a far more sensible level of RTC at default settings which is enough to make the responsiveness very good.

 

Input Lag

 

As usual I tested the screen in clone mode with a CRT to determine the level of input lag. This is something which can put off some gamers and is a delay between graphics card and monitor output. By hooking up a CRT you can show that  the LCD lags behind somewhat, which can affect users in some situations where they rely on the screen image being as fast as their inputs (e.g. fast FPS shooting games). Often, input lag is very low and probably wouldn't represent too much of a problem in real terms.

The NEC 2490WUXi was only average in this test I'm afraid. While the responsiveness tests had proved very pleasing, the input lag of the screen was behind that of some other competing screens. It was faster than some models such as the Dell 2408WFP (64.1ms) and Samsung SM245T (52.5ms) on average, but not as fast as the HP LP2475W (25ms) or the Samsung SM245B (7.5ms). This isn't to say it is unusable or anything, but some hard core gamers might find it a little distracting for very fast paced gaming. The input lag did range between 30ms and 40ms typically, but sometimes reached even higher at around 50 - 60ms.

 

Movies and Video

The following summarises the movie and video capabilities of the 2490WUXi:

• 24" screen size and 16:10 aspect ratio are a nice size for movie playback, and a good corss over between desktop monitor and LCD TV

• 1920 x 1200 resolution can support true 1080p HD content resolutions

• HDCP supported over digital interfaces for compatibility with protected content such as Blu-Ray

• Good black depth once calibrated and once backlight intensity is altered. This is important for viewing dark scenes, where detail can be detected more easily

• Standard sRGB colour gamut meaning colours do not appear oversaturated and 'neon' in non colour aware applications such as watching movies

• Wide viewing angles thanks to H-IPS panel technology, meaning minimal contrast and colour shift when viewing the screen from different angles, when compared with other panel technologies

• Good panel uniformity on the whole, and no noticeable backlight bleed from the edges or corners, which can be problematic when watching movies with black borders

• Fast response time means fast moving images and action packed scenes show minimal ghosting and blurring. This model is more responsive in practice than many other competing 24" models we have tested in fact

• Noise is fairly noticeable due to the screen size and resolution, and particularly apparent with low definition content. Sitting a sensible distance away alleviates the issue

• Multiple interface options available including VGA and 2x DVI. However, there are no additional connections which would have been handy for this type of use, especially if you wanted to connect external devices to the screen. HDMI, Component and DisplayPort are missing, but available on some competing models. HDMI in particular is becoming more and more useful from modern displays.

• There are no specific 'multimedia' enhancements here such as Picture In Picture (PiP) or Picture By Picture (PbP) which some people may find useful on other models

• There is also no dynamic contrast mode on this model, which some users may find useful. Not a big issue though as many dislike this feature

• Screen is compatible with optional add-on sound bar for simple all-in-one multimedia solution

 

Conclusion

Overall I was thoroughly impressed with the NEC 2490WUXi. I can see now why the screen has proved popular already in the USA, and I can only hope that the market is open to the screen in Europe and the UK. The RRP of �799 is pretty steep compared with competing models such as the Dell 2408WFP, NEC 24WMGX3 and HP LP2475W, which can all be had for around �400 - 450. Once the  2490WUXi becomes more readily available though, I should expect to see that price fall at e-tailers, and if the price is  more sensible, this could be a good choice.

Price aside, the screen offers some very impressive performance. Colour accuracy is excellent, and even black depth and contrast ratio are very good which is pleasing for an IPS panel. The advanced features such as 12-bit LUT and hardware calibration help set this model apart from others, and secure it a spot as a great screen for colour enthusiasts. Responsiveness is even very good, which is a pleasing result for this type of screen, and its use in gaming is only let down by its fairly poor input lag. Viewing angles, office use and ergonomic are all very good as you might expect, and all in all, this is a very good screen. If you can get it at a reasonable price, it really can fit a whole range of uses.