Files & prepress
What is DPI vs PPI?
PPI is the pixel density of a digital image; DPI is the dot density a printer lays down — the trade uses them interchangeably, and what actually matters for signage is the image's effective resolution at the final printed size.
The distinction is real but rarely decisive: a file has pixels (PPI), a printer makes dots (DPI), and neither number on its own says whether a graphic will look sharp. A 300 PPI image is only '300' at one physical size — double the print size and its effective resolution halves.
Sign work is more forgiving than business cards because viewing distance does the flattering: 100–150 effective DPI is fine for most banners, and billboards run far lower. The number to check is always effective resolution at final size, never the number typed in the file's metadata.
Calculate effective DPI instantly — free checker →
Related terms
Software that speaks the trade
PrinterFlo runs print & sign shops on one board — quotes that price by size and material, proofs approved from one link, and a production checklist the quote writes for you.