Print Resolution
Print resolution describes pixel density at a print's actual output size, measured in pixels per inch (PPI). It's computed by dividing an image's pixel dimensions by the intended print dimensions — a 6,000-pixel-wide file printed at 20 inches wide works out to 300 PPI.
The required density depends on viewing distance, not a fixed universal number: 300 PPI targets close examination (roughly a foot away), while a large print viewed from several feet needs far less density to look equally sharp. This is derived from human visual acuity, roughly one arc-minute of resolvable angle, which sets a specific required PPI for any given viewing distance rather than one flat rule for every print size.
Frequently Asked Questions
Is 300 DPI always the right target for printing?
Only for prints genuinely viewed up close, like a photo book or a small desk print — a large print viewed from across a room needs meaningfully less density to look equally sharp, since the requirement scales with viewing distance.
What's the difference between print resolution and camera resolution?
Camera resolution (megapixels) is the total pixel count captured; print resolution (PPI) is how densely those pixels are spread across a specific physical print size — the same file produces a different PPI at every different print size.