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Measurement And Calibration Methodology: How We Test

NEC PA272W 27-Inch Monitor Review: Accuracy And Flexibility
By

To measure and calibrate monitors, we use an i1Pro spectrophotometer, a Spectracal C6 colorimeter, and version 5.2.0.1374 of SpectraCal’s CalMAN software.

The i1Pro is very accurate and consistent measuring color on all types of displays, regardless of the backlight technology used. When we just need a luminance value, the C6 works better, especially in low light.

For patterns, we employ an AccuPel DVG-5000 video signal generator. This approach removes video cards and drivers from the signal chain, allowing the display to receive true reference patterns. Connections are made via HDMI.

The AccuPel DVG-5000 is capable of generating all types of video signals at any resolution and refresh rate up to 1920x1080 at 60 Hz. It can also display motion patterns to evaluate a monitor's video processing capabilities, with 3D patterns available in every format. This allows us to measure color and grayscale performance, crosstalk, and ghosting in 3D content via the 3D glasses.

The i1Pro or C6 is placed at the center of the screen (unless we’re measuring uniformity) and sealed against it to block out any ambient light. The AccuPel pattern generator (bottom-left) is controlled via USB by CalMAN, which is running on the Dell XPS laptop on the right.

Our version of CalMAN Ultimate allows me to design all of the screens and workflows to best suit the purpose at hand. To that end, I’ve created a display review workflow from scratch. This way, we can be sure and collect all the necessary data with a concise and efficient set of measurements.

The charts show us the RGB levels, gamma response, and Delta E error for every brightness point from zero to 100 percent. The table shows us the raw data for each measurement. And the area in the upper-left tells us luminance, average gamma, Delta E, and contrast ratio. The individual charts can be copied to the Windows clipboard to easily create graphics for our reviews.

Every primary and secondary color is measured at 20-, 40-, 60-, 80-, and 100-percent saturation. The color saturation level is simply the distance from the white point on the CIE chart. You can see the targets moving out from white in a straight line. The further a point is from center, the greater the saturation until you hit 100 percent at the edge of the gamut triangle. This shows us the display’s response at a cross-section of color points. Many monitors score well when only the 100-percent saturations are measured. Hitting the targets at the lower saturations is more difficult, and factors into our average Delta E value (which explains why our Delta E values are sometimes higher than those reported by other publications).

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  • 4 Hide
    SuckRaven , June 12, 2014 6:52 AM
    Every time Tom's Hardware reviews monitors, I keep posting in the comments that they should review NEC and EIZO for accuracy in comparison to the usual suspects. Finally my prayers have been answered. (Not that there are not other places that have not already done a good job of including reviews of high-end monitors with color accuracy, and uniformity as the main focus), but Tom's has always been a preferred resource. Anyways, you guys should do a shootout with the top flagships from HP, Dell, NEC and and EIZO, perhaps the CG277). Nice review.
  • 1 Hide
    Pikker , June 12, 2014 7:34 AM
    I've recently purchased this monitor with calibration tools and hood for a discounted price, needless to say it looks incredible, putting to shame an older 27" IPS display that I had.
    Regarding the NEC 272 vs. Eizo 277, I think they are more same than different... the Eizo has an integrated calibrator, 16-bit LUT, bigger color space, and a bunch of other tweaks that should objectively make it a better display, but not ~$1000 better IMO. If you have that kinda money to burn, get two PA272W's instead.
  • 0 Hide
    ubercake , June 12, 2014 8:33 AM
    Good review.

    I think everyone should notice the low-cost IPS monitors offer sub-par contrast. Who cares about color accuracy if you can't see the in-betweens? Aren't the shades/hues just as important? This is something people don't realize when they pick up that $400 IPS display. Heck, contrast is better on the BenQ TN display than on the less expensive IPS displays in the review. Color without good contrast is a waste. Contrast is what you compromise at the lower end of the IPS monitor scale.

    You have to spend money to get a quality IPS monitor. It's good to see that you can get this kind of performance at a lower price point now.

    This NEC monitor is definitely impressive. It has great color accuracy AND contrast. Great for photography and graphic arts/design applications. This is a pro monitor and why you spend money on an IPS monitor.
  • 0 Hide
    RedJaron , June 12, 2014 9:28 AM
    I have a dream that one day I will own such a display.
  • 0 Hide
    ceberle , June 14, 2014 1:53 PM
    Quote:
    Every time Tom's Hardware reviews monitors, I keep posting in the comments that they should review NEC and EIZO for accuracy in comparison to the usual suspects. Finally my prayers have been answered. (Not that there are not other places that have not already done a good job of including reviews of high-end monitors with color accuracy, and uniformity as the main focus), but Tom's has always been a preferred resource. Anyways, you guys should do a shootout with the top flagships from HP, Dell, NEC and and EIZO, perhaps the CG277). Nice review.


    Look for a review of the HP Z27x in a few weeks. It's in our lab now.

    -Christian-
  • 0 Hide
    PapaCrazy , June 15, 2014 7:38 PM
    Bought one of these and ended up with a display that had several dead pixels and a couple hot pixels. Exchanged it, got a display with even more deal pixels, I stopped counting in the teens. For $1400, seems offensive. Dell was offering a zero dead pixel guarantee for half the price with the u2711. Calibrated, it seems to do quite well in color accuracy, I never get complaints after file deliveries, but the Dell is made like a piece of shit. Has a major heating problem which effects the top (where the heat collects) of the display's color output after intensive usage. I'm sick of this over-inflated display market. They are either under-engineered or overpriced.
  • 0 Hide
    Pikker , June 16, 2014 4:01 AM
    Quote:
    Bought one of these and ended up with a display that had several dead pixels and a couple hot pixels. Exchanged it, got a display with even more deal pixels, I stopped counting in the teens. For $1400, seems offensive.


    That's some bad luck... I got mine from B&H and the display was perfect out of the box. Otherwise, the thing is built like a tank with an all-metal frame under the plastic outer shell, and it doesn't flex no matter what, if anything, I'd say it's over-engineered.
  • 0 Hide
    PapaCrazy , June 16, 2014 12:52 PM
    Quote:
    Quote:
    Bought one of these and ended up with a display that had several dead pixels and a couple hot pixels. Exchanged it, got a display with even more deal pixels, I stopped counting in the teens. For $1400, seems offensive.


    That's some bad luck... I got mine from B&H and the display was perfect out of the box. Otherwise, the thing is built like a tank with an all-metal frame under the plastic outer shell, and it doesn't flex no matter what, if anything, I'd say it's over-engineered.


    Got mine from B&H too. NEC released an upgraded model w/ improved colorimeter shortly after my purchase. It could very well have been an accumulation of old stock, the backwash of sorts, that I drank from. When studying up, I found the only way to get a guarantee of zero dead pixels on NEC displays, you need to pony up for the ultra-expensive medical grade displays. It is well made though, I thought the portrait mode was a great feature and the stand was far more solid than the Dell's. Ran cooler as well. (thermally I mean)