Pixel density

Pixels per square metre — (1000 ÷ pitch)², the size-independent way to compare pitches.

Pixel density is how many pixels a square metre of wall carries: (1000 ÷ pitch in mm)². A 2.5 mm wall has 160,000 px/m²; 1.25 mm has 640,000 px/m² — four times the pixels for half the pitch, which is also why cost rises so steeply.

Density (not resolution) is the honest comparison between products, because resolution depends on how big a wall you happen to build.