Why this is the right question for new work
Checking an existing photo asks “what will this file bear?” Commissioning a poster, a canvas, or a book cover asks the opposite: “what file should I make?” Pixels = inches × DPI. An 18×24 inch poster at 150 DPI needs 2700×3600 pixels (9.7 MP). The same poster at 300 DPI needs 5400×7200 (38.9 MP). Design at the larger size if type and fine lines matter; 150 DPI is often enough for photographic posters viewed from a step back.
Bleed and wrap
Canvas wrap and press bleed are extra. A 16×20 canvas with 1.5 inches of wrap on each side is really 19×23 of image. Multiply those inches by your DPI, not the visible face. The POD checker flags wrap in the notes; always confirm the vendor template.
Questions people actually ask
- How many pixels for a 16×20 at 300 DPI?
- 4800×6000 pixels, 28.8 megapixels, if the image already matches 4:5. A 3:2 camera file must be larger on the short side or you will crop.
- Is 150 DPI enough for a t-shirt?
- Many DTG catalogs publish 150 DPI as a minimum for a 12×16 print area (1800×2400 px). Fine linework and small type look better at 300 DPI (3600×4800).