Labs

LCD Monitor price test 2006

We put all the LCD screens in this group though a barrage of exacting tests to uncover any deficiencies in the quality of the images they produce.

Our solid colour tests are used to spot uneven backlighting or inaccurate colours. Black should be pitch dark, with no light leakage either through the panel or around the bezel, and white should be pure without any coloured tint. Primary colours should be vivid and uniform across the entire screen area.

We used a number of high-resolution photos to examine colour accuracy. Some portrait pictures reproduce skin tones in astonishing detail and often reveal unbalanced colours. Skin texture is another good test of how well a screen picks out fine detail - some do this better than others.

To test a monitor's ability to display all brightness levels accurately, we used an image of a smooth greyscale gradation from black to white. Panels should be able to distinguish every shade of grey in between, but this is seldom the case. There are a number of common problems, included banding, where the brightness dips in large noticeable steps, and discoloured bands, where colour creeps into what should be a black-and-white image. Many monitors can't display either or both extremes of the gradient, with the scale becoming too bright or too dark too soon.

All the monitors have a stated pixel response time, but we test all screens with a variety of fast-moving images. These segments taken from games and movies enable us to assess the suitability of each screen for entertainment use.

Although we recommend using a digital visual interface (DVI) connection where possible, we test each screen using both analogue and digital inputs. DVI should produce a perfect image, and most modern LCD screens can convert an analogue signal into a sharp image at the touch of a button.