(Credit: Joseph Maldonado)
We test desktop monitors of all stripes here at PCMag, from barebones budget screens to moderately priced mainstream displays to high-end, big-screen Ultra High Definition (UHD) models that cost thousands of dollars. Every monitor we review is subjected to a series of image-quality and performance tests that we use to draw a comparison to other monitors in the same class, which in turn helps us to assign a rating to each panel. Read on to see how we test monitors.
Basic Settings: What We Tweak, What We Don't
We first test all monitors in an out-of-the-box state. We do not calibrate the monitor or tweak color settings unless special circumstances require it, in which case we explain what we adjusted and why in the review.
To ensure accurate, comparable, and repeatable testing results, we use the monitor's Standard picture mode while testing and turn off all digital processing settings (such as dynamic contrast ratio, adaptive contrast, and color and black-level enhancers). The monitor is always tested at its native resolution via DisplayPort (assuming DisplayPort is supported). If it is not, we fall back to HDMI.
(Credit: Joseph Maldonado)If the monitor has specialized color configurations built in (Adobe RGB, DCI-P3, and the like), we will also test those presets using the matching settings in our CalMAN testing software.
Our Testing Suite: The Gear and the Software We Use
To test monitors, we use Portrait Displays' CalMAN monitor calibration software, a Murideo Six-G signal generator, and a Klein K10-A colorimeter to take the measurements.
(Credit: Portrait Displays/PCMag)CalMAN is a professional-level program most often used to calibrate monitors and televisions to be as color-accurate as possible. To that end, it comes with a host of tools that accurately measure color variance, luminance output, and overall color quality for any monitor we're testing.
(Credit: Molly Flores)Hooked into CalMAN on our test bench via our testbed PC is the Klein K10-A, a colorimeter that we use to take the measurements directly off the surface of the screen. As an intermediary display device, we also deploy a Murideo Six-G signal generator to guarantee that all colors sent to the screen and scanned by the Klein K10-A are accurate to the color-space standard we are testing (Rec. 709, DCI-P3, and so on).
Testing Procedure: How We Measure What We Measure
To test color accuracy, we let the monitor warm up for at least 30 minutes, and we use the CalMAN software in concert with the Klein colorimeter to measure the monitor's color accuracy, compared with the sRGB, Adobe RGB, and DCI-P3 standards, and the manufacturer's claims about each.
To gather these results, we point our Klein directly at the middle of the panel using an 18% window size. (This is in reference to the size of the testing window relative to the full size of the screen.) We set a 3-second delay for each run (indicating the amount of time a color will appear onscreen, and when the Klein K10-A takes its reading).
(Credit: Joseph Maldonado)We capture the color data, and CalMAN plots the results on a chromaticity chart like this one...
(Credit: Portrait Displays/PCMag)Colored dots represent our measurements, while the boxes indicate the chromaticity coordinates. CalMAN also generates a percentage indicating the monitor's coverage of the color space in question, which we report.
After that, using the luminance sweep feature, we test the monitor's peak SDR and HDR luminance ratings, expressed as a peak lux figure in candelas per square meter (cd/m2, or nits). This process also gives us our gamma readings (a measure of the luminance level at which pixels on the monitor display colors) and the contrast ratio. We calculate the contrast ratio by taking the peak lux and dividing that number by the lowest recorded black level of the monitor.
Finally, if the monitor we're testing is intended for gaming, we use the Leo Bodnar 4K Input Lag Tester to measure its input lag times across various refresh-rate and resolution combinations. Low input lag is critical for hard-core gaming and esports, but you can benefit from it even if you're just a casual gamer.
Non-Quantitative Testing: Eyes Only
Our non-quantitative testing includes examining everything involved in the design of the monitor and its cabinet, while gauging it against competing models. This includes factors such as the overall aesthetic, the thickness of the bezels, the placement and selection of video inputs and other ports, the stand's adjustability and styling, and any VESA-mounting compatibility. We also report on the ease of use (or lack thereof) of the on-screen menus and their controls on the cabinet.
On monitors with HDR functionality, we watch some 4K test clips to gauge how well the content looks on the monitor. We also view a standard folder of high-resolution images to see how well a monitor might perform in Photoshop and other creative applications.
(Credit: Joseph Maldonado)We test viewing-angle performance (how the display looks when observed from top, bottom, and side angles) by looking for any variations in luminance and color fidelity at various off-center angles. We use standard images to detect faded blacks in text, color shifting (where whites appear tan and reds may take on a brownish tone), and posterization (in which subtle grades of color disappear into broad patches). We also check for dimming and washed-out images when viewed off-center, both common issues in cheaper monitors.