Measurement And Calibration Methodology: How We Test
To measure and calibrate monitors, we use an i1Pro spectrophotometer and version 5.0.3 of SpectraCal’s CalMAN software.
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 HP ZR30w is a wide-gamut monitor designed to conform to the AdobeRGB 1998 spec. Therefore, we benchmarked it against that standard. You’ll see in the chromaticity charts that we plotted the results relative to the larger color gamut. Delta E values are also expressed using those same color points. There are no calibration controls available except for brightness. You can vary the monitor’s total light output with the plus and minus keys on the front bezel. There is no on-screen menu to let you know what the setting is. You have to adjust it by eye or with some type of meter, as we do.
Since this monitor is incompatible with the 1920x1080 signals from the Accupel generator, we utilized the CalPC Client from SpectraCAL as a substitute pattern source. All video driver settings were carefully checked to be sure the graphics card didn’t affect our readings.
The DoubleSight DS-309W is also a wide-gamut panel and has a full set of adjustments including high and low range RGB controls. We first saw this on the Asus PB278Q that we reviewed last month, and liked the fact that it allows for very precise adjustment of the monitor’s grayscale at all brightness levels.
After experimenting with the brightness and contrast controls, we found they work more like a television rather than a computer monitor. Normally, we increase the contrast to a point right before the highest-level details are clipped (blend into one another), then adjust light output with the brightness slider. The DoubleSight operates in the opposite way. Brightness affects the overall black level so we set this as low as possible while maintaining detail down to the minimum signal level. While this resulted in a fairly high black level measurement, setting the control any lower would clip information. The contrast has a narrow window of usable adjustment. Moving it more than a few clicks above the halfway point would crush top-end information and cause a visible color shift towards red. You can lower it as far as you want without harming accuracy. To dial in the max output at 200 cd/m2, we set it to a value of 33.
The sharpness control is set to a default value of 12, but because it appeared to have no effect on digital signals, we set it to zero.
|Gain||Red 55 / Green 47 / Blue 45|
|Offset||Red 54 / Green 48 / Blue 50|
Obviously, there are no recommended settings for the HP ZR2740w. You can set the Brightness either by eye or by measuring the level with a meter.