Understanding DPI and Print Resolution
DPI (Dots Per Inch) measures how many ink dots are printed per inch, determining print sharpness. The more pixels you pack into a physical inch, the crisper the output. The formula is simple: pixels = print size (inches) × DPI. For metric sizes, convert mm to inches by dividing by 25.4.
The optimal DPI depends on viewing distance. Business cards and photos viewed up close need 300+ DPI. Large banners seen from several feet away only need 72–150 DPI. Billboards viewed from tens of meters away need as little as 15–30 DPI.
File Format and Color Mode
Print files should use CMYK color mode (not RGB) to minimize color shift after printing. High-resolution TIFF or PDF formats are recommended. If using JPEG, save at maximum quality (level 12) to avoid compression artifacts in the final print.
Frequently Asked Questions
The human eye cannot distinguish individual dots above 300 DPI at a typical 12-inch viewing distance. Higher DPI has minimal quality benefit and increases file size.
They're viewed from a distance. The farther the viewer, the less detail they can distinguish. 72–150 DPI is perfectly sharp for banners viewed from several feet.
A4 (8.27 × 11.69 in) at 300 DPI = approximately 2,480 × 3,508 pixels. Formula: inches × DPI = pixels.