DPI

DPI describes printer dot density, while PPI (pixels per inch) describes how an image’s pixels are distributed at a chosen print size. The terms are often used interchangeably by print services, but pixel dimensions are what determine whether an image contains enough detail.

To estimate print size, divide each pixel dimension by the target PPI. A 3000 × 2000 pixel image placed at 300 PPI prints at 10 × 6.67 inches. At 150 PPI it prints at 20 × 13.33 inches. A value near 300 PPI is a common target for closely viewed photo prints, while posters viewed farther away may work at a lower value. Requirements vary by printer, paper, image detail, and viewing distance, so check the print provider’s specification.

Changing only the DPI or PPI metadata does not create detail or add pixels. If the image is too small for the required print size, print smaller, accept a lower effective PPI, or upscale a copy before printing. Inspect the result at the intended size because upscaling can improve apparent sharpness but cannot recover every detail absent from the source.