How We Test Monitors

PC World's testing philosophy has always been--and continues to be--to evaluate computer products in real-world settings, with applications that an average PC user is likely to use day in and day out. We test the image quality of monitors by using a jury of PC World editors and analysts, as well as outside evaluators. The testing methodology we use was developed by and is the property of the PC World Test Center.

Test Environment

We place the monitors on long tables of even height and depth. To eliminate interference between monitors during testing, we separate monitors from one another by at least 18 inches. We use common overhead fluorescent lighting in our test room in order to simulate a typical office setting. Each monitor is attached to one of eight matched PCs with ATI Radeon 9000 Pro graphics cards. To eliminate any brand bias our panel of testers might have, we put cardboard shields over the monitors' bezels. Jurors sit a consistent distance from each monitor in common office chairs.

To ensure consistency across test batches, we include a previously tested baseline monitor with the new monitors in each test batch. Our current baseline 19-inch monitor is the first version of the ViewSonic VP912b. Our current baseline 17-inch monitor is the Dell UltraSharp 1704FPV.

Jury Profile

Each of our image-quality jurors is required to have 20/20 vision; corrective lenses are acceptable. The jury is made up of two groups: An experienced team of six editors, PC World Test Center analysts, and other staffers who review monitors every month, and six people who are not professional reviewers and are hired through a temporary staff agency. This diversity helps mitigate any biases that someone who tests monitors month after month may develop. Each monitor receives 12 sets of scores; we throw out the high and low scores, and average the remaining 10.

The Main Group of Tests

Each member of our jury individually scores the quality of 11 different screen images. Jury members are also asked to choose the best and worst displays, and to briefly explain their decisions. As noted below, some of the test screens were produced by the PC World Test Center; some came from DisplayMate Technologies' DisplayMate for Windows Multimedia with Motion version 2.10, a video-diagnostics utility; and the rest came from other sources.

Plain white screen: We use this test to check for hot spots as well as for brightness and color uniformity from the center of the screen to the corners.

Alternating E's and M's in 14-point Times New Roman type: This test was developed by the PC World Test Center with help from the University of California at Berkeley. It shows how uniformly a monitor displays text across the screen, and it highlights any difficulty in displaying diagonal lines smoothly.

Microsoft Word text document: This screen shows how well a monitor displays typical text documents with various text formats.

Microsoft Excel spreadsheet: A typical spreadsheet with columns of numbers in 8-point Arial and with cells in reverse type, this screen lets us judge the sharpness of text, icons, and shadows.

Varying Fonts: Provided by DisplayMate, this is a split-screen view of white text (an excerpt of the Declaration of Independence) on a black background and of black text on a white background. It shows how clearly a monitor can display the same text in different sizes. Small fonts are often noticeably sharper on better monitors than they are on inferior units.

Fine black-and-white vertical bars: Each black-and-white vertical bar is just 1 pixel wide. The screen helps us identify monitors that have more screen flicker and shimmer than is typical.

Gray Scale Chart: This DisplayMate test shows how accurately a monitor displays shades of gray at the black and the white ends of the grayscale spectrum.

Color Scale Chart: Another test from DisplayMate, this screen helps us assess color accuracy and the smoothness of color transitions and shading (also known as linearity).

Web-page screen: We use an image that includes pictures of fine art to evaluate combined text and graphics at various points around the screen.

Color photo 1: This detailed, very colorful digital photo of a fruit tart lets us check a monitor's color accuracy, saturation, and detail.

Color photo 2: An image of a group portrait lets us test for skin-tone accuracy as well as for detail and overall color precision.

LCD Motion Tests

With current technology, LCD pixels have slower image redraw rates (also known as response times) than do CRT phosphors. Because of this, the user of an LCD monitor may see jittering or ghost images, most noticeably in fast-moving 3D games. Consequently, we conduct two additional tests to evaluate an LCD's ability to display smooth motion: We view a looping demo from Return to Castle Wolfenstein, a high-end 3D game; and we load a screen shot of DisplayMate's home page (with four small detailed graphics in the center) and move it around the screen (as you might pan around an oversize image in an image editor). LCDs with slow response times will display minor jumps and jitters as the image moves.

LCD Angle-of-View Test

We place each LCD on a custom-made platform that consists of a base with degree markings, a sight, and a rotating monitor stand. Using the "Hardware Gray-Scale Linearity Check" screen, we rotate the LCD to the left and to the right until the outer and inner rectangles appear the same to the human eye. We then record the angle from the markings on the base.