Introduction - Design, OSD, and Viewing Angles

Our monitor reviews frequently go into a lot of depth about the results before and after calibration, but for many users this won’t matter, as they aren’t going to purchase the calibration hardware and software necessary to achieve these results. Getting accurate performance out of the box without needing to spend extra money on hardware is important to many people but it's often very hard to deliver. With their Pro Art monitors, ASUS aims to deliver just that: sRGB and AdobeRGB modes that are reasonably accurate (a dE < 5.0 out of the box), with a full set of controls for users to calibrate it on their own.

ASUS doesn’t stop there as they also offer a 10-bit panel, integrated card reader and USB ports, and a user calibration mode with more controls than I have seen on a consumer monitor to this point. Does the ASUS deliver good color out of the box, and have the performance for those that wish to calibrate themselves?

The design of the ASUS PA246Q is all business out of the box. With a goal of high performance and not sleek looks, the PA246Q looks like a generic LCD monitor from a couple of years ago. As long as you're after performance rather than style, this shouldn't be a problem (provided the performance is actually there). The left side of the display features a pair of USB ports and a card reader than handles most formats with the exception of Compact Flash. On the bottom of the display you will find DVI, HDMI, DisplayPort, and VGA inputs as well as the power supply and downstream USB connection. There are no integrated speakers but there is a headphone jack for audio carried over HDMI or DisplayPort, though it is located somewhat inconveniently at the bottom of the monitor.

The attached stand is pretty sizable but offers a full range of adjustments. Height adjustment is good with a decent range, and the tilt function has a good amount of movement that is always useful when trying to calibrate with a large meter on the screen. With swivel and pivoting as well, the stand is as good as the Dell stands that I prefer, though it certainly takes up a lot of desk space. I certainly don’t feel the need to replace the stand with an aftermarket one, though.

The OSD offers up a lot of options for the end user, but the interface for it is only OK. Under the Splendid section of the menu we find six different picture modes: Standard, sRGB, AdobeRGB, Scenery, Theater, and User. I will ignore Scenery and Theater, as they provide a blown out color palette or intentionally dim image for those that are swayed by such things. sRGB and AdobeRGB are the pre-configured modes that are designed to hit those primary color points and have a dE < 5 straight out of the box. The only control available to users in these modes is brightness to adjust the level of the backlight and everything else is locked. Standard mode is what you find on most monitors, with the standard Brightness, Contrast, Color Temperature and Gamma controls available for adjustments.

The most interesting mode is the User mode, which has the same features as Standard but opens up Hue and Saturation controls, as well as a 6-point CMS with Hue and Saturation controls for each primary and secondary color, and a 2-point grayscale control. This enables you to dial in those color points to be reasonably accurate on the CIE graph, but as there is no individual luminance control for each color, you can only get the color correct in two dimensions and not all three. I will go over these settings more in the calibration section, but they are quite extensive for a computer display.

There are a few more settings to be found in the menu system, but nothing out of the ordinary, and there is no game mode or overdrive for enabling faster response from the display (not that we've really noticed an improvement with such modes on other LCDs). The OSD controls themselves are sufficient but somewhat cumbersome, as we see the common issue of the display having you move up and down to select items, then left and right to adjust those items, with only one set of input keys for both. It would help to have either a second set of arrow keys for adjusting the values, or design the menu so it only moves in one direction to make it more user friendly. It is worlds better than using touch sensitive controls but still not at the level that some other menu systems are at this point.

Using an IPS panel, we expect good viewing angles from the PA246Q and we get them. At the very extreme angles you get some brightness shift but overall the panel looks very good at any angle you might be looking at it from.

Now that we’ve taken an overview of the ASUS PA246Q the question is to see how it performs on the bench, and if I can deliver the out of the box accurate colors it promises.

ASUS PA246Q - Brightness and Contrast Ratios

As important as color accuracy is, everything starts with the dynamic range a display offers, which is based on its contrast ratio and brightness. If you have perfect colors but very little dynamic range, you won’t be able to distinguish light from dark, or have shadows or highlights that have any depth to them. Cranked up to the maximum with a calibrated screen, I obtained 284 nits of light from the PA246Q, and at the minimum setting I managed 104 nits. Since this is from a calibrated setting, the maximum output is reduced. You can push all of your settings to the maximum and get a brighter image from the PA246Q but it will be excessively green tinted as green has the highest light output of the primary colors.

Even with it only producing 284 nits, this is more than enough for any work environment it will see in the real world. The minimum output is a little higher than I would prefer, as some people work as low as 80 or 100 nits for print work, but it isn’t awful. IPS traditionally doesn't excel in black levels compared to VA panels, and the PA246Q doesn’t have a dynamic LED lighting system or any other technology to try to improve this. Because of this we have a really high black level on the PA246Q, with the lowest value I could obtain being 0.16 nits. I don’t use a 100% black screen for these measurements as that allows some panels to totally turn off the backlight and it’s not applicable to any real-world use, but I have a small amount of light at the edges of the screen for testing. Because of this you can potentially coax better numbers out of some displays than whay I report, but I don’t feel they have any real world application.

With this higher black level, we manage to get a contrast ratio that is pretty ordinary at best. Coming in at around 650:1 this comes in close to some of the inexpensive TN displays we've reviewed, along with the cheaper IPS panels that have been in the lab. Other models are able to pull out 1000:1 or better, which is what I would like to see out of a high-end panel now. Most of these panels aren’t using a wide spectrum backlight that can support the AdobeRGB colorspace, and that support might be what is causing the higher black levels and lower contrast ratio, so it is something users would have to consider when evaluating the PA246Q for their use.

Overall the brightness numbers for the PA246Q are good, but the black level and therefore contrast ratio numbers leave a little more to be desired from a display at this price point.

ASUS PA246Q - Color Quality

ASUS promises a dE < 5 out of the box with their sRGB and AdobeRGB modes, but do they deliver? Well, yes and no. The problem with this promise is that you have to decide how you are going to measure dE for the display. Do we just measure the dE for white, or grayscale, or grayscale plus the primary colors? Or should we measure the full Gretag Macbeth color checker chart and expect a dE below 5 there? Also, should we use dE 1976, 1994, 2000, or something else? Since none of these are specified, I am unsure how to judge ASUS, other than against other monitors with our standard GMB testing.

Out of the box in sRGB mode we see that performance isn’t any better or worse than other displays for the most part. However the grayscale is overall very good, and the primary colors are decent for the most part with dE values that are relatively low. If I’m judging the <5 claim based on this, the PA246Q might live up to expectations. Once I move into certain shades of blue, however, the dE really gets high, and so using the whole spectrum I can’t say that it manages <5 dE for the sRGB mode. Perhaps they are using a different dE formula than we are, or perhaps they are only claiming that white will be below 5, but using the same standard we apply to other vendors, the PA246Q isn't any better or worse out of the box than the competition.

So out of the box the calibration seems fine but not exceptional, but does it calibrate well for those that need it? Overall the calibrated dE of 2.06 looks a little high, but when we examine the graph we see that the grayscale is much higher than any other display in the chart. This is a bit weird, and leads me to wonder how well the two-point grayscale calibrates and is handled internally. I set that for 100% and 30% as those should lead to a fairly accurate grayscale across the gamut, but here it seems to be good at 100% and then really ramp up. If the math is incorrect internally, this could lead to these issues where it has those two points correct, but determining the values for points between them is done incorrectly.

When I broke out the data more, the average dE for the color patches was 2.08 for the ASUS, which is almost equal to the overall value. For other monitors I had data for, the colors were on average 0.25 dE higher than the total dE with grayscale. So it seems that colors are better on the ASUS, but the grayscale is worse. In this case if you are doing photo editing, it might be a better choice than if you are using it for black and white work or even general-purpose work. With spreadsheets and word processing, you don’t notice a tint since the white is very good overall, but dark shadows can be off. So overall the performance of the ASUS PA246Q here was good for color and fairly poor for grayscale, which is different than almost any other display we have seen.

With 100 nits, the grayscale was much better and so the better colors led to a dE that was lower than with 200 nits. Because of this the ASUS seems to be a better performer for print work than for brighter rooms, but really the main area it fails is for black and white photo editing with a brighter screen.

ASUS says they can do the full AdobeRGB gamut on this display and they aren’t lying. With almost 107% coverage it will work well for photographers and other professionals that need the larger gamut.

ASUS PA246Q - Display Uniformity

The large viewing angles allowed by an IPS panel only truly help if colors are accurate at the edges of the screen and not just in the center. On the PA246Q the lower-left of the panel seems to be brighter than the rest of it, as it is close to the same level as the center of the screen but the right and top sides of the panel are a bit dimmer. Even with those sides being dimmer, that is better than most displays where all sides are dimmer instead of just 50% of them. So white uniformity is better than average, but not perfect.

Black uniformity shows the same pattern, only in this case as the lower-left is brighter, it has worse performance that the upper right. If these black levels look worse than the previous black levels we discussed, these are set with the backlight at the level needed for 200 nits of white, which was around 40 brightness on this display.

Because I have the data, I added another chart this time, Contrast Uniformity. This simply takes the previous two charts and shows the relative contrast across the screen. Surprisingly the worst contrast was in the dead center of the display, so perhaps if I were to go back and do this chart for other displays I would find the contrast number we use is a worst-case-scenario. In any case, I plan to use this going forward as well since we already have the data, and we can see how close the contrast ratio is across the screen. Here the standard deviation is only 4.26%, which is lower than both the white and black uniformity deviations. So if you are dimmer in white, you’ll be darker in black by a comparable degree it seems.

Finally we can look at the dE uniformity of the PA246Q. Broken down by color the dE values are close for the most part, though the lower-left section of the screen is clearly way off on the grayscale and in most other colors relative to the rest of the screen. Surprisingly the center-bottom of the screen outperforms the center, which is what we calibrate to as our target, which is a bit strange. The average deviation for each sample is almost half a dE, which is a pretty large deviation when you consider that the average dE is right around 2. Overall the PA246Q seems mostly uniform, but with a couple outliers here that tend to skew the data.

More on the PA246Q CMS

As mentioned earlier, the PA246Q offers a CMS (Color Management System) to the end user in User mode. While a CMS is becoming more and more common on TVs and projectors, they are not too common on computer displays at this point. Since they aren’t too common, I’ll describe how they work a bit, and what they should do when correctly implemented.

Many of you are probably familiar with the CIE 1931 color space diagram. It shows all colors and inside you will see a triangle indicating the area of all visible colors that a monitor can display. For each color gamut, there are primary color points for Red, Green, and Blue, and a target point for White. Since we are using sRGB typically, we use D65 as a white point, which has its own xy coordinates, and then each primary color has its own xy coordinates. This is pretty easy to understand, as there is an x-axis and a y-axis on the CIE diagram.

The controls that are available to us in the PA246Q CMS are individual controls for each primary and secondary color for Hue and Saturation. Hue controls the rotation of the color point around the white point. For example, adjusting the hue moves the red from green towards blue, or from blue towards green when adjusted the other way. Saturation controls the distance from the white point. Increasing saturation moves the point from the center towards the edge of the diagram, and reducing saturation brings it inside. With these two controls you should be able to get all six color points to wind up on their target coordinates. That results in a perfect display, right? Wrong.

There is a third variable for color that isn’t visible here, and that is Y, or the luminance/light-output of the color. Each color should be a certain brightness when compared to white. Blue is around 7% of the brightness of white, Red is around 21%, and Green is around 71%. These percentages help you understand why blue color errors are less visible than green color errors, since blue is 1/10^th as bright in most cases. So without this extra value to adjust, we can’t control if the luminance of an individual color is too high or too low, which can cause a tint or color shift in the image, as a certain color can be too bright relative to everything else.

Now that we have discussed that, you can see that this isn’t a full CMS as we’re missing a key control. Luminance is often considered to be more important than Hue or Saturation for the primary colors, so not having this control can make a large impact on the quality of the controls. The other thing a CMS must do is correctly calculate the values for each color based on how you calibrated the display. With the CMS all you are doing is programming in the targets for what the ideal points are, but those are six points out of one billion colors with a 10-bit display. To render the other colors correctly, the display must now take those adjustments and apply the math correctly to get the intermediate colors correct.

To be honest, most displays are really bad at this. Even $10,000 projectors have CMS systems that don’t calculate these correctly, though I’ve also seen $1,000 plasma displays with CMS systems that are spot on perfect. This is where the CMS on the ASUS falls short. While I could get the reference points to be perfect, the intermediate points were far, far off the target and led to an image that looked pretty bad. Leaving these at the default and only setting the white point led to much better results in the end. I think it is a good progression that ASUS is adding a CMS to their displays, as properly implemented it lets you get the monitor nearly perfect internally before you apply the calibration inside the graphics card. However, if the CMS doesn’t seem to work correctly, you are better off leaving it alone and then doing the calibration only in software using the video card LUT.

ASUS PA246Q - Input Lag and Power Use

There is no overdrive or game mode on the PA246Q, as it is targeted at graphics and design with gaming as something you might do in your spare time. Despite that, it does reasonably well with just over a frame of lag from our measurements. There is a 10ms input delay for processing the image, and then 24ms of rise and fall time for the pixels themselves, leaving to a total lag of 22ms. Your effective lag is probably right around 16-17ms, so a single frame. It isn’t the fastest gaming monitor out there, but it isn’t bad either.

With its CCFL backlighting system, the PA246Q is not a power efficient display. At minimum brightness it uses more power than the 27” HP ZR2740w and uses just slightly less at maximum brightness despite having maximum light output that is only 65% of that in the HP. Of course it does have a much larger gamut enabled by the CCFL backlighting system, but it does take a lot more power to do so.

The ASUS PA246Q comes designed to compete at the higher end of LCDs, with a 16:10 aspect ratio, AdobeRGB color gamut, 10-bit panel (using ARFC to extend a native 8-bit panel), and a fully adjustable stand. It also promises better performance out of the box than other displays, so you don’t need to own calibration equipment to get a more accurate image, and has a full CMS that you don’t see on PC monitors very often.

In a few places it delivers but in others it falls short. The out of the box performance might have met their dE target, but there are so many different ways to determine the average dE and no method is given here, so I can’t determine for sure if ASUS is achieving their goal. What I can determine is how it rates using our standard measurements; unfortunately, it came in at the same level as other displays when looking at real world, Gretag Macbeth colors on the color checker chart. Once calibrated the performance is good for colors, but the grayscale is off by quite a bit delivers overall inaccurate color reproduction compared to other high-end displays.

From a strictly personal view, the screen itself looks very nice and clean, and the anti-glare coating shouldn’t distract anyone I don’t think. Much as high-end projectors are said to give a “film-like” image, the PA246Q image looks very nice and natural in daily use. Even with my personal preferences towards the image it produces, the higher black levels and lower contrast ratios also leave a bit to be desired and leads me to wonder when we can finally get a backlit, RGB LED array display to address this.

The one area that really isn’t there yet is the CMS system. While very promising for the future with displays, I would like to see a full 3D system and not 2D, so that you can get all the primary and secondary points dialed in correctly. The main issue is that the math for determining the intermediate points doesn’t seem to be correct, which leads to an image with banding in gradients and image posterization. This is another reason that typical measurements of display performance often fall short as if you only measure the six target points the CMS would look fantastic, but the other billion points look much worse in real life.

Overall the ASUS PA246Q does a lot of things well and is even acceptable for gaming, but it doesn’t do anything amazingly well. I would say it is a great general-purpose display, but the price tag puts it well beyond that category for most people as it clearly aims for a higher level of use. One main competitor would be the Dell U2410, but I haven’t reviewed that so I can’t say how it would stack up in comparison. If the ASUS came in closer to $350-400 it would be easy to recommend, but at nearly $500 with calibrated results that leave a bit to be desired in the grayscale I find that harder to do.

Since I haven’t used the main competitors, the ASUS PA246Q could easily be the best choice in its price range if you need IPS, AdobeRGB, a 16:10 ratio, an ergonomic stand, and decent calibrated results. It just isn’t exceptional enough at what it does for me to be able to unconditionally recommend it for everyone.