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We tested this ourselves and found that out of the box the screen used a slightly lower 34.8W of power. After calibration, where we had adjusted the brightness control and therefore the backlight intensity, this was reduced to 20.7W. In standby the screen uses only 0.7W of power. This was very comparable of course to the other W-LED + IPS models we have tested like the Asus ML239H and NEC EA232WMi. I also tested the screen with the 'Super Energy Saving' mode on. This seemed to make very little change, no matter what brightness setting I was at, only really dropping the power consumption by 1 - 2W. I'm not sure what this mode is supposed to do really. I have provided a comparison graph below of several screens we have tested:
The Panel and Backlighting Unit The LG IPS231P utilises an LG.Display LM230WF3-SLB1 e-IPS panel which is capable of producing 16.7 million colours. The panel itself actually uses a 6-bit colour depth with frame rate control (A-FRC) to produce the 16.7m colours. This is different to regular 8-bit IPS matrices, but this is likely a measure taken to achieve a lower price point for these modern lower-cost displays. Studying detailed information from LG.Display's datasheet confirms the panel is indeed 6-bit+AFRC. The IPS231P uses White-LED (W-LED) backlighting. The colour space of this screen is approximately equal to the sRGB reference (and around 72% NTSC) and the screen is therefore classified as a standard gamut model.
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 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.
The out of the box performance of the IPS231P was reasonable. The CIE diagram on the left confirms that the monitors colour gamut (black triangle) very closely matches the sRGB colour space (orange triangle). It extends a little past the sRGB space in blues and greens in this 2D view of gamut. Default gamma was recorded at 2.0 average, leaving it 10% out from the target of 2.2. Keep in mind that the screens OSD gamma setting was at 2.2, so this is obviously a little out from reality. We will try to find the optimum screen gamma setting in a moment. White point was excellent here and very close to the target at 6411k (1% deviance) which shows a good factory set up in this area.
Luminance was recorded at a high 273 cd/m2 which is perhaps not surprising given that the screen is set at 100% brightness by default. This was in fact a little higher even than the specified maximum brightness of 250 cd/m2. This should be easy enough to adjust later during our calibration. Even at this high 273 cd/m2 luminance, the black depth was a very good 0.30 cd/m2. This gave us a static contrast ratio of 920:1 which is excellent for an IPS panel.
Colour accuracy was mediocre at default factory settings with an average dE of 3.1, ranging up to a maximum of 5.6. The screen felt quite even to the naked eye although overly bright at these default settings and perhaps a little washed out. Some minor OSD adjustments can hopefully help improve the default set up for casual users who don't have access to a hardware calibration device.
We wanted to test the screens other gamma settings to see if there was a better setting than the default 2.2 (which had returned measured gamma average of 2.0). We found that an OSD setting of 2.4 returned a gamma average of 2.2 (2% deviance) which was a better starting point. All other settings remained the same and we still retained an accurate colour temperature / white point of 6430k (1% deviance). Colour accuracy was actually improved a little as well with dE average now 2.0 (down from 3.1) and maximum pretty much as it was at 5.5 (down slightly from 5.6). Luminance still needs to be tamed, but adjusting the brightness control down to around 10% should return a more comfortable luminance of around 120 cd/m2. This gamma mode is definitely a better starting point and should provide a better out of the box performance than the default setting.
I wanted to calibrate and profile the screen to determine what was possible with optimum settings and profiling. 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.
I remained in the user mode preset for this process and changing the color temp mode to 'user' allowed me to adjust the RGB controls from within the OSD menu individually. I followed LaCie's calibration process through, adjusting the OSD settings in line with the recommendations made in the process, and then letting the software carry out the LUT adjustments at a graphics card level and create an ICC profile. The screen does not feature a hardware LUT calibration option so other than the OSD alterations, the rest of the process is carried out at a graphics card level in profiling the screen.
The calibration was a success. The slight gamma discrepancy that we saw before (1%) had been corrected now to leave us with 0% deviance from the target of 2.2 and white point was basically spot on at 6507k. Luminance had been reduced to a more comfortable 120 cd/m2 after the adjustment of the OSD brightness control to 11%. Black depth was still very good at 0.14 cd/m2 and this gave us a very good calibrated static contrast ratio of 860:1. Colour accuracy was also improved nicely with dE average now 0.4 and maximum only 1.4. LaCie would consider colour fidelity to be excellent.
Testing the screen with various colour gradients showed very smooth transitions with no sign of any colour banding. There was some slight gradation evident in darker tones but overall no issues. There was also some slight temporal noise evident, particularly in darker tones if you look very closely. This is a result of the FRC algorithm used to produce the 16.7 million colour palette. It's not something you'd notice in practice to be honest, and you do have to look very closely to see it.
You can use our settings and try our calibrated ICC profile if you wish, which is available in our ICC profile database.
Calibration Performance Comparisons
I've provided a comparison above of the IPS231P against some of the other screens we have tested in a similar size range. Out of the box average dE was 3.1 on the IPS231P which was mediocre. It was better than the BenQ EW2420. That model used one of AU Optronics' AMVA panels with W-LED backlighting. Default colour accuracy of the EW2420 was worse at 4.8. The default colour accuracy of the IPS231P was comparable, although not quite as good, as some of the other 23" IPS models we have tested including the Dell U2311H (2.4), NEC EA231WMi (2.7) and Viewsonic VP2365wb (2.5). Even thought the IPS231P was a little higher at 3.1 this is a minimal difference really out of the box and still reasonable. The other 23" IPS + W-LED screens we have tested are the NEC EA232WMi (2.4) and the Asus ML239H (2.3). These screens are using the same panel as the IPS231P. The professional grade 23" NEC PA231W was better still at 1.3 dE average. A reasonable performance in terms of default colour accuracy from the LG IPS231P and only a little behind the competition really.
Once calibrated the dE average was reduced to 0.4. This would be classified as excellent colour fidelity by LaCie. It was not quite as low as some of the other screens here which reached down to 0.2 average, but in practice you would not notice any real difference here. Some of the professional range models from NEC are even more accurate. Professional grade monitors like the NEC PA series also offer other high end features which separate them from some of these other models, including extended internal processing, 3D LUT's and hardware calibration. These comparisons are based on a small selection of tests, so it should be remembered that other factors do come into play when you start talking about professional use. For further information and tests of a high end professional grade screen with hardware LUT calibration, you may want to have a read of our NEC SpectraView Reference 271 review.
The black depth and contrast ratio of the IPS231P were very good for an IPS panel. Calibrated black depth was 0.14 cd/m2 which was very close to the other 23" IPS screens we have tested (ranging between 0.13 and 0.17 cd/m2). The NEC EA232WMi is the closest rival to the IPS231P and had a slight better calibrated black depth of 0.13 but this is marginal. The LG was slightly ahead of the Asus ML239H though which had a calibrated black depth of 0.16. Contrast ratio was a very good 860:1 but it was a little behind a few the others in this regard. The NEC EA232WMi again was a little better with a 933:1 static contrast ratio thanks to its lower black point. However the LG was better than the Asus ML239H (749:1) and pretty much identical to the popular Dell U2311H (857:1). The BenQ EW2420 and Samsung F2380 with their AMVA and cPVA panels respectively offered some fantastic contrast ratios of ~3000:1 which IPS cannot compete with at the moment.
I wanted to see how much variance there was in the screens contrast as we adjusted the monitor setting for brightness. In theory, brightness and contrast are two independent parameters, and good contrast is a requirement regardless of the brightness adjustment. Unfortunately, such is not always the case in practice. We recorded the screens luminance and black depth at various OSD brightness settings, and calculated the contrast ratio from there. Graphics card settings were left at default with no ICC profile or calibration active. Tests were made using an NEC branded and customised X-rite i1 Display 2 colorimeter. It should be noted that we used the BasICColor calibration software here to record these, and so luminance at default settings may vary a little from the LaCie Blue Eye Pro report.
The luminance range of the screen was decent enough at the top end although not as high as some modern screens. At 100% brightness control, the screen was able to offer a maximum luminance of 270 cd/m2 which is even a little higher than the advertised 250 cd/m2 maximum luminance. At the lower end the screen perhaps does not reach as low as you might hope, only ranging down to as low as 107 cd/m2. Some users may want to achieve a lower luminance than this, but it is not possible using simply the backlight control. Any further adjustments would need to be made at a digital white/black level using the contrast control, graphics card changes or altering the graphics card LUT. This would be at the sacrifice of contrast however. A setting of around 10% at default settings should return a luminance of around 120 cd/m2 for comfortable day to day use in normal lighting conditions. If you carry out further calibration or adjustments of contrast or the individual RGB channels this of course may vary.
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. Black depth was good across the whole range, being between 0.30 and 0.12 cd/m2. This was good for an IPS panel and only a little behind some other competing (IPS based) models. This could also not compete with the modern AMVA and cPVA panels that we have seen.
Contrast remained stable across the range with an average static figure of 885:1 recorded based on a default uncalibrated state. These contrast measurements were plotted on the graph shown above.
The DCR feature is only available in the 'user' and 'movie' presets from the 'mode' menu. The brightness control remains active in the OSD menu and is not greyed out as it is on some screens. There is actually no setting for this DCR in the menu so you cannot turn it on or off. Instead, if you enter these preset modes, it is always active.
The tests that we carry out to measure dynamic contrast ratio involve an almost completely white and almost completely black screen. In real use you are very unlikely to ever see a full black or full white screen, and even our tests are an extreme case. Carrying out the tests in this way does give you a good indication of the screens dynamic contrast ratio in real life situations however. Carrying out this test in the 'movie' preset mode didn't seem to make use of the DCR at all. There was no noticeable change in the backlight intensity when changing between images of different levels of white and black, even when switching between an almost completely white, and an almost completely black image. Our colorimeter recorded maximum luminance as 132 cd/m2 and minimum black depth of 0.21 cd/m2. This gave us a contrast ratio which was in fact much lower than the the default static contrast ratio and was recorded at 631:1. Having switched to the 'movie' mode, the colours and gamma of the screen were altered massively, making everything seem overly vivid and saturated, and with a higher gamma than needed. The section of the OSD that would normally let you control colour temp, RGB, gamma etc was now greyed out so this 'movie' preset mode was a fixed setting with an appearance which felt very unrealistic. This produced this lower contrast ratio of 631:1 which for all intents and purposes was just a static contrast ratio. The DCR didn't seem to work at all. Nothing particularly surprising considering some of the DCR performances we have seen from many other models. However, the feature can work, but only in the most unrealistic and extreme circumstances. Like the Asus ML239H that we tested recently, if you display an all black screen (completely black) then the feature "works". You can see a change when viewing an all black screen which takes about 2 seconds to happen. The screen goes so dark that it seems to turn the backlight off completely after a couple of seconds. Unlike on the Asus, where you could view the OSD disappearing, if you have the OSD active on the LG then it keeps this from happening. You can detect it easily enough with the naked eye, and it only appears to happen on a 100% black screen. If you then return to any other image the screen comes back on and returns to the normal state within a couple of seconds again. This was the only way I could get the DCR to work at all. So the technology appears to be switching the backlight off completely which would account for the ridiculously high DCR of 50 million:1. In the right lab settings you can achieve this DCR (in fact its tending towards infinity:1 if you consider its black point is basically the backlight turned off = 0 cd/m2.). However, in practice you are never going to be able to see a DCR range like that. In fact in normal use the DCR doesn't seem to operate at all. Another marketing gimmick and a disappointing trend it seems.
Viewing angles of the LG IPS231P are very good, as you would expect from a screen based on an e-IPS panel. Horizontally there are very wide fields of view with a small contrast shift only really becoming noticeable from a fairly wide angle of about 45�. Vertically, the contrast shift was a little more pronounced but the fields of view were still very good. Vertically there is a slight pink hue noticeable as you move your field of view away from a central position and at an extreme angle this turns a little yellow. This is only really a problem at extreme angles though. The panel is free from any off-centre contrast shift which you see from VA matrices, and this is why IPS technology is so highly regarded in the colour enthusiast and professional space. It is also free of the very noticeable contrast and colour tone shifts you see from TN Film panels vertically. On a black image there is a slight purple hue, certainly less noticeable than some other screens like the Asus ML239H, when viewed from an angle but there is no obvious white glow that you can see from some modern IPS panels. There is no A-TW polarizer on this panel which is rarely used now in the market. 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 The luminance uniformity of the IPS231P sample was pretty good overall. The maximum deviations from the central measurement of 120 cd/m2 were as low as 102 cd/m2 along the left hand edge and up to the highest measurement of 121 cd/m2 around the central area. Overall 86% of the screen was within 10% deviance from the target which was good and 46% of it was measured within 5% deviance. The left hand edge of the screen was a little darker than the rest of the screen but you couldn't spot this in normal use.
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. Overall the appearance of an all black screen appeared pretty even in this test. There was some slight leakage of the backlight from the four corners, most noticeably from the bottom right hand corner. In normal use you wouldn't notice this and it was quite minimal thankfully.
The 23" screen size and high 1920 x 1080 resolution were very pleasant for office working, and although you do lose a bit of height vertically compared with a 1920 x 1200 screen, it was nothing too bad. Image quality was very crisp and sharp using the DVI interface, and although D-sub (VGA) was also very good, it was not quite as sharp on text I didn't think. The 0.265 mm pixel pitch was slightly smaller than a 23.6" 1920 x 1080 screen of course (0.2715 mm) and 24" 1920 x 1080 screen (0.276 mm), and so text size felt about right for every day use. Default luminance of the screen was too high for prolonged office use at 273 cd/m2, although this was with the screen set at 100% brightness. For comfortable use in normal lighting conditions a setting of around 10% should return you a luminance of ~120 cd/m2. There was a specific 'text' preset mode available from within the OSD menu although it made the image a little more yellow than our calibrated 'user' mode. It probably won't be of much use to many if they set up their 'user' profile for normal day to day use. The ergonomics of the screen offered a good wide range of adjustments. It was good to see a full range of height, tilt, pivot and swivel available although they were not the easiest to use sadly. At least you should be able to position the screen at a comfortable setting for your individual preferences. It was a bit of a shame not to see some USB ports available and there are no extra features like ambient light sensors and card readers which are often useful in office environments. These have been left off to keep production and retail costs down. At least there are some integrated speakers available I suppose for casual 'office' type sounds and occasional videos / music. However the sound is not that loud and quite tinny with no real bass. Don't plan on watching movies using these!
The screen is designed to run at its native resolution of 1920 x 1080 and at a 60Hz recommended refresh rate. However, if you want you are able to run the screen outside of this resolution. We tested the screen at a lower 1680 x 1050 resolution to see how the screen handles the interpolation of the resolution. At native resolution the text was very sharp as you can see from the top photograph. When you switch to a lower resolution the text is noticeably more blurry, even more so than some other screens we have tested. There is a lot of overlapping of the text across sub-pixels as you can see in the photo which results in this blurring. Native resolution is recommended where possible.
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, 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:
Unlike some other screens we have tested of late, there is not option in the OSD menu to turn the 'response time' up or down. You must therefore rely on LG's factory setting in this area. The IPS231P is rated by LG as having a 5ms G2G response time which implies the use of response time compensation (RTC) technology which is used to boost pixel transitions across grey to grey changes. The LM230WF3 panel itself is rated by LG.Display (the panel manufacturer) as having a 14ms ISO response time as well which signifies the black > white transition. Have a read about response time in our specs section if any of this is new to you. I have provided a comparison of the IPS231P above against the two other screens we have tested which use the same panel as this screen. On paper the LG IPS231P should perform better than the NEC EA232WMi since it is using RTC and the NEC is not. The Asus ML239H is rated with a 5ms G2G response time as well so on paper appears to be the same as the LG model. In practice however the IPS231P performs far more like the NEC screen, which does not have any overdrive / RTC impulse applied to it. There is a noticeable motion blur and trail behind the moving car on the LG screen. The moving image is certainly less sharp than the Asus screen. Perhaps LG have decided to not apply much in the way of an RTC impulse here at all (if any)? Unfortunately you cannot control the level of RTC from the OSD menu so you cannot turn this up or down at all. On the plus side, without an aggressive RTC impulse seemingly being active on this screen, it is at least free of any noticeable overshoot. Where RTC impulses are applied too aggressively or not controlled well this can sometimes lead to dark / pale trailing behind a moving object which can be just as distracting and problematic as motion blur in the worst cases. There's no sign of any overshoot here on this model.
I've also provided some comparisons of the
IPS231P against some of the popular and recent 24" models in the market we have
tested. As you can see, the IPS231P is a bit faster than the AMVA based
BenQ
EW2420, which to be quite honest, did not perform very well in this test.
It is a little behind the cPVA based
Samsung F2380 we tested recently which has an 8ms G2G response time. The
Dell U2410 and
HP
ZR24W both use RTC and so their performance was better still and showed some
of the best responsiveness of all of these models in practice.
I've also included a comparison above against two gamer-orientated screens, both featuring heavily overdriven TN Film panels, and 120Hz technology. The pixel responsiveness of both of these is ahead of the IPS231P, and the 120Hz frequency allows for improved 120fps frame rates and the support of 3D content as well. The BenQ XL2410T does show some rather noticeable RTC overshoot in the form of dark trails behind the moving image (speech bubble and head) which is unfortunate, and a sign that the RTC impulse is too aggressive. The Samsung 2233RZ remains our champion in this test.
Aspect Ratio Control - The IPS231P supports aspect ratio control options through the OSD 'others' menu as shown above. There are only options for 'original' and 'wide' here though so they are fairly limited. Complete 1:1 pixel mapping is lacking here. Preset Modes - There is no game' preset mode available in the menu sadly. The dynamic contrast ratio is only available in the 'movie' preset although we have already seen that this does nothing in real use unfortunately.
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 input lag of the IPS231P was very low with an average of only 6.9ms. The delay ranged between 0 and 20ms maximum. This was very good and should not present any problems for gaming. It was a little faster than the Asus ML239H (15ms) and NEC EA232WMi (8.1ms) which was good.
The following summarises the screens performance in video applications:
The influx of new IPS panels into the 23" market is certainly making it a very competitive area and its always interesting to see what LG themselves will offer based on one of their own panels. In the case of the IPS231P I think I can sum this screen up as: a good general all rounder which would suit casual day to day or office work well. The design and features of the screen are fairly standard really and its a simple, modest display and stand. It's good to see the decent range of ergonomic adjustments available here which will suit an office environment well, although they were let down a little by their wobbly feel and stiffness in some cases. There's no fancy extras and only a D-sub and DVI interface available so this isn't a screen for those wanting a multimedia display for lots of devices, or something that will look stunning sat on their desk. However, what the IPS231P does do, it does well enough. Colour accuracy, black depth and contrast ratio were all very good and even the out of the box settings were decent enough. Viewing angles were wide, uniformity was decent and responsiveness was ok. Again, a good screen generally all round thanks to its e-IPS panel technology, but there's nothing which grabs you really here. The input lag was very low which was good, but then if you are looking at a gaming screen then you would probably want something with a better response time.
In terms of
retail cost the IPS231P currently sells for ~�150 GBP which is very competitive.
In comparison at the time of writing the Asus ML239H is ~�180, the Dell U2311H
is ~�200 and the NEC EA232WMi is ~�240. So there is quite a saving to be made if
you just want a decent display for all round office type work and don't need any
fancy extras.
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