Glossary → PPI (pixels per inch)
PPI (pixels per inch).
how many image pixels fall on each inch of the printed size
The resolution of an image at a given print size: pixel width divided by print width in inches. It is what most upload specs mean when they write DPI. ArtStation spells out the sum, 300 ppi times 10 inches is 3000 px, so a 10 × 8 inch print needs 3000 × 2400 px, and warns not to confuse PPI with DPI, the ink droplets its printers lay down at up to 2400 × 1200 dpi. Sawgrass recommends working at 300 Pixels/Inch for sublimation. The figure stored in the file is only a tag: Redbubble says DPI and PPI don't affect the uploaded image and publishes pixel minimums instead. Divide the pixels by the inches before trusting the tag, because a resize without resampling changes the PPI and not the detail. In book production the same letters mean pages per inch.
Where this matters: Sublimation › Resolution at print size · Wall decor › Poster size in pixels: print area and pixel size · Resolution and DPI › Pixel sizes instead of DPI · KDP spine width, bleed and cover size › Resolution at print size · Stickers › Resolution at print size
Related terms: PPI (pages per inch)