Out-Of-Box Performance: Color Accuracy And Gamut
We are using a Spectracal-certified X-Rite i1Pro, along with CalMan, to report color gamut and color accuracy. For those unfamiliar with the terms, color gamut refers to the range of colors that a display can reproduce, and color accuracy refers to the display's ability to output the color requested by the GPU. Typically, professionals represent these values by showing a gamut and a delta E value, which is a mathematical representation of how far apart the display's output is to the original source. The higher the delta E value, the more inaccurate the color representation. An uncalibrated delta E is largely a worthless number. Delta E is dependent on the black and white luminance levels, contrast ratio, color temperature, and target gamma.
Suppose there are two displays. One has an uncalibrated delta E value of 3.0, and the other, 2.1. It is hard to make a comparison without first calibrating the color space. It's almost like benchmarking a GeForce GTX 580 at 2560x1600 with anti-aliasing enabled against a Radeon HD 5870 at 1920x1080 without AA. Do the results of that test mean the 580 performs better? Not necessarily. Monitor calibration is to display quality what quality settings are to game benchmarks. By calibrating a display, we are able to normalize the settings and see how one display compares to another.
For this reason, we’re going to provide information in the form of a color gamut map, along with a gamut luminance chart. This gives you a better picture of how a display performs, both fresh out of the box and once it's calibrated.
Color Gamut and Accuracy
CalMan uses specific targets, which are displayed as squares in the gamut xy map. The dots are the actual measured values. Gamut luminance expresses how bright the primary and secondary colors are in relation to the source color requested by the GPU (gray bars are target values).
Gamut CIE XY Map
Expectedly, all three IPS monitors deliver excess amounts of color compared to TN-based displays. DoubleSight's DS-277W and NEC's PA271W both produce nearly 100% of the AdobeRGB 1998 color gamut in perceptual rendering (read our printer paper benchmarks if you want an explanation of perceptual rendering). Dell seems to fall below it's 96% spec because it's approximating a white point further from 6500 K.
As we turn to color quality, all three monitors attempt to map our reference points to the equivalent hues in a larger gamut. This is a trend that we see with IPS monitors, as they try to capitalize on the superior color production capabilities that TN-based panels can't achieve. However, the luminance values are very close between each display. As we move to larger color gamuts, you'll find it difficult to distinguish differences between monitors, even with lab equipment.