NEC PA302W Review
NEC top of the line displays keep getting better. The PA302, PA272W and PA242W are the latest generation of color-critical displays intended for color professionals like photographers, designers and pre-press departments. They have a new list of improvements over the previous generation (PA301W, PA271W, PA241W).
The big news in these new PA2 series is the use of new Light Emitting Diodes (LED’s) as the source of backlight. While white LED’s have been used for years in displays, they have not been able to provide the kind of wide color gamut that we look for in this kind of display. The PA2 series uses GB-R LED’s which have green and blue diodes coated with a red phosphor. These not only produce a large gamut, but the power distribution between them can be adjusted, allowing for precise control of the white point. This means that the actual color of the backlight can be custom-tuned instead of depending on the LCD’s to filter the color appropriately. We have not been able to have a custom white point since the old CRT days! (There were a few attempts at RGB LED’s, but I’m not counting that.) This means if you like to run with a different white point than usual, this hardware will dial it around much more easily than having to depend on the LCD filters to maintain the white color. You should keep in mind, however, that it is designed for a white point close to 6500 Kelvin, which is equivalent to a daylight-type of white which most people are expecting.
This new backlighting technology provides a number of useful improvements.
The PA302W, like it’s siblings the PA242 and the PA272W has a wide color gamut. The use of LED backlighting makes for a slight increase in the color gamut over the previous generation of NEC monitors that used CCFL backlighting. NEC claims that the PA302W produces 99% of the AdobeRGB color spectrum. Our own tests show the 302 has a gamut volume of about 1,374,000 cubit Lab values. This is actually larger than the gamut volume of AdobeRGB (1,207,000) because the NEC covers a larger area than does AdobeRGB. The NEC produces more reds and magentas than AdobeRGB, but AdobeRGB has a very small amount of saturated greens not covered by the NEC.
Because of the new backlighting and the internal color sensors, the PA2 series of displays offers color consistency that we didn’t see before. You can buy several units and expect them to match each other very closely when calibrated. You could even use different PA2 models such as a 242 for storing your pallets and a 302 for viewing your images.
Another thing you want a quality monitor for is consistency of color across the screen. Your cheap monitor off the shelf might produce a lot of color, but those who work professionally with image manipulation need a display that will be as accurate with the color in one corner of the display as it is in the opposite corner. A great way to check this is to fill your screen with a blank white (or off-white) image and see if you can detect irregularities in the color of white on the screen. At CHROMiX, we go a step further and measure the color in 9 quadrants across the screen, comparing the results to each other to see where the largest differences are. A delta E value of less than 1.0 is not visible to the human eye. A delta E of less than 3.0 is considered quite good. NEC corrects uniformity problems with a feature called Digital Uniformity Compensation. The PA302 we tested was mostly in the 2-3 range, with a couple of areas where it was over 3. These were the upper left to upper right corner, and the lower left to the lower right corner. This is still very much in the range of good uniformity. This issue of uniformity is quite important since a monitor that is not uniform will only get worse as it ages.
The original PA series had a built-in brightness sensor only which kept track of and made adjustments to the brightness of the display. Now the sensor monitors both brightness and white point color. This backlight sensor automatically adjusts to keep the appearance of the display consistent. This begins to work as soon as the backlight starts up when you turn it on, so the display can be warmed up to the correct viewing condition in a very short time. As usual, you would not want to calibrate it until it has warmed up for at least 30 minutes. However your display color will be stable enough to begin your work far sooner than that.
There is a small color distortion visible in the lower right corner of our demo model. But this is limited to the very edge of the screen and should not be a problem for normal color use. Some variation in the uniformity near the edges of a display like this is not unusual.
Since color-critical viewing is normally done at modest brightness levels, the ability to reproduce a dark black on an LCD monitor is critical to keeping a good contrast ratio. Using a high quality colorimeter like an i1 Display Pro - or the NEC equivalent which is called a "SpectraSensor Pro" - The PA series produces some very good, dark blacks.
|Black level using i1Display Pro
|At 120 cd/m2 we measured a black level of >
|At 110 cd/m2 we measured a black level of >
|At 60 cd/m2 we measured a black level of >
In order to view color on a display without being distracted by the reflection off a shiny surface, a high-quality display is finished with a fine, speckled coating that diffuses the light and greatly reduces reflections. NEC got enough complaints about their coating being too heavy on the original PA series that they have re-adjusted this new series to have a lighter coating. This anti-glare coating formulation is less pronounced, is more uniformly distributed, and at the same time sufficiently reduces glare.
NEC is unique in that it offers two programs for use in profiling the display. For the high end professional or pro-sumer, we recommend using the SpectraView II software with a colorimeter to calibrate and profile the display on a regular basis. This is the best way to ensure color consistency, month-by-month, for years to come. The SpectraView II software has all the bells and whistles you need to create a good profile, will allow you to set your desired white point, gamma and brightness. I have covered the SpectraView II software in my previous reviews.
Here’s an interesting note: NEC markets these PA2 displays to the world outside of the US as the “display that never needs calibration.” While we might scoff at this claim in the US, NEC has tried very hard to make this possible. The MultiProfiler software does not require a measurement device. It is closely tied to the photospectrophotometer measurements that were used to calibrate the display before it left the factory. NEC has algorithms to anticipate changes to the display over time, and an internal sensor that keeps track of the color and brightness of the screen. MultiProfiler will make a profile based on the factory measurements, and according to your desired white point, brightness, etc.
Certainly when the display is new, we would expect MultiProfiler to be able to make profiles very close to what we would get using a traditional colorimeter-based calibration. Since the displays also have a built in luminance and color sensor, they should also be able to keep this accuracy over time.
Some PA2 displays can also be calibrated by the basICColor Display calibration software. This is one of the few 3rd party software products that will also talk with the internal graphics of the display and make a quality calibration and profile.
It goes without saying that this series has all the regular features we have not mentioned so far: Wide angle viewing, 14-bit internal graphics card to handle the color calibration, adjustable stand including portrait orientation,
Other features of secondary importance to photographers
10-bit color support to the monitor
For those looking to have a continuous 10-bit throughput from Photoshop to the display, this display will not limit you. It’s ready when the rest of your workflow is. (You’ll need to use a compliant operating system and video card though.)
Switchable between computers
DisplaySync Pro is what NEC calls the internal USB hub that allows you to connect the display to two computers. With this you can use one display with one keyboard and mouse and switch between two different computers. Not everyone will have a use for this, but some of us still have an old computer sitting around that we are still using because it’s the only thing that will still run some app that we love. This feature makes it very easy to switch to that computer using the same keyboard, mouse and display.
PWM Pulse Width Modulation
Color-critical displays operate at much lower brightness levels than other displays. In order to create a lower brightness, the NEC hardware alternates the light on and off at a very fast rate. This flicker to our eyes looks like a lower brightness. Due to the limitations of the technology, the cold-cathode fluorescent tubes (CCFL) used to flicker at less than 300 cycles a second. Some people who are sensitive to flickering used to notice this. With the introduction of the LED backlighting, technology now allows them to cycle this modulation anywhere from 20,000 to 49,000 cycles per second.
These new LED’s have less power consumption. The PA302W uses 40% less power than its predecessor. LED’s tend to get physically hot, and in order to cool these displays have thicker cases than normal in order to allow for more air flow through the case. This works very well, and the displays are not warm to the touch, and NEC has wisely decided against using fans to cool the displays. The passive air flow works in both the horizontal and vertical orientation. Naturally the display case is a bit chunkier in order to accomplish this internal cooling. The PA302W is about 3 inches thick. The 302 cabinet is actually a little thinner and lighter than the 272.
User reset of calibration
Due to the changes in the hardware, the software can offer new features: The PA2 series can now have its factory settings reset by the user. While it’s not generally recommended, if someone wants to do this using their own instrument, they can.
Links and other information:
- 2560 x 1600 native resolution
- 1000:1 contrast ratio
- 340 cd/m2 brightness
- DisplayPort, Mini DisplayPort, DVI-D, HDMI
- Viewing Angle 89º/89º (178oVert. 178o Hor.)
- Warranty 4 years parts and labor, including backlight
- Additional Features: USB hub (2 up/3 down) with DisplaySync Pro, Picture-in-Picture, Side-by-Side, ICC Profile Emulation, 14-bit 3D gamma, Adobe RGB, ECO Mode, cable management, touch-integratable, tilt, swivel, pivot, height-adjustable stand with locking base, No Touch Auto Adjust, quick release stand, VESA Mount
- All tests were run at 120 cd/m2, 6500 K, 2.2 gamma unless otherwise noted.
March 20, 2014