Testing guides

Short, practical walkthroughs. Each one answers a single question and takes you to the test that answers it.

Display tests

How to test a new monitorTest a new monitor on day one, while it can still go back: set the native resolution, then check dead pixels, backlight bleed, uniformity, banding, gamma, refresh rate and ghosting in your browser. The whole check takes about 10 minutes.
Dead pixel vs stuck pixel vs hot pixel: what is the difference?A dead pixel stays black on every color, and no software can repair it. A stuck pixel stays lit in one color and a hot pixel stays white, both easiest to see on black; either can sometimes recover.
How to calibrate a monitor without a colorimeterWithout a colorimeter you can set four things by eye: brightness, so the darkest gray steps just separate from black; contrast, so the brightest stay distinct from white; gamma, to about 2.2; and white balance, until gray shows no tint. Color accuracy needs a colorimeter.
How to test a used laptop before you buy itCheck the case and hinges, then run the screen, keyboard, touchpad, speaker, microphone and webcam tests in the laptop’s own browser and try every port and the charger. Battery health and the serial number come from the operating system; allow about 15 minutes.

Camera or microphone blocked? How to allow access in your browserAllow the site from your browser’s address bar or site settings, then check that Windows, macOS or your phone lets the browser itself use the camera and microphone. If it still fails, close other apps using the device and check shutters, mute keys and cables.