Print resolution is measured in dots per inch (DPI). Too low and artwork looks soft or pixelated; at the right DPI, type and images stay sharp on press.
Standard expectations
For most offset and digital print, 300 DPI at final size is the standard. Large-format signage often uses 150 DPI or lower because viewing distance is greater.
Setting up your file
Create your document at the final trim size and set resolution to 300 DPI before you design. Scaling up a low-resolution image in layout will not improve quality.