Screen Sharpness Test

In short One-pixel lines and checkerboard patterns are the fastest way to find out whether the image reaching your screen is being scaled, because scaling destroys exactly that kind of fine detail. If you see shimmering, moiré or uneven line spacing, something in the chain is resampling: the display is not running at its native resolution, the browser is not at 100% zoom, or a television is applying its own sharpening. Check browser zoom first — it is the most common cause and the easiest to leave at 110% by accident after zooming a page weeks ago. If text looks fine but the patterns shimmer, that points at zoom rather than at the panel. On a television, look for a sharpness control and set it to zero or its neutral point: TV sharpness settings add artificial edge enhancement that looks impressive on a shop floor and destroys fine detail on a computer signal. Many televisions also need a specific input label, often "PC", before they stop processing the image entirely.