Pixel pitch

Pixel pitch is the only number that matters when specifying an LED wall, because everything else follows from it. A smaller pitch means more LEDs per square metre, which means a sharper image, a higher price and more power. Vendors write it as a number in millimetres, sometimes prefixed: P2.5 and 2.5 mm are the same thing.

The rule of thumb is roughly one metre of viewing distance per millimetre of pitch. A 2.9 mm wall reads cleanly from about three metres, which is fine through a shop window onto a pavement. A boardroom where somebody presents from beside the screen needs to be down around 1.2 mm, and that costs several times as much for the same area.

Pitch is where the money goes, and vendors rarely say so plainly. Samsung publishes three prices for the same cabinet: at 1.68 mm, 1.26 mm and 0.84 mm the figures are $5,200, $6,600 and $12,900. Halving the pitch roughly doubles the cost, so the honest question is not how fine a wall can be but how close anyone will actually stand.