Resolution

Resolution measures how finely an image is rendered. For displays, it is expressed in pixels (e.g., 300×300 pixels); for print, in dpi (dots per inch). In QR codes, resolution directly affects scan success rates and print quality.

Each module (the smallest black or white square) needs a minimum number of pixels or dots to be reliably identified by scanners. For smartphone scanning, at least 4 pixels per module on screen and 0.3 mm per module in print are practical guidelines. At 300 dpi, 0.3 mm equals roughly 3.5 dots - sufficient for reliable scanning.

Insufficient resolution causes module boundaries to blur, leading to scan failures. The most common problem is scaling up a low-resolution PNG image. Raster images develop jagged edges (aliasing) when enlarged, making module boundaries unclear. SVG (vector format) solves this fundamentally - since shapes are defined mathematically, resolution never degrades regardless of scale. Use SVG for web display and PNG at 300 dpi or higher for print.