IMAGE PREFLIGHT
DPI, PPI, and Image Size for Print
Pixels divided by placed inches gives effective PPI; printer requirements and viewing distance determine whether it is suitable.
SHORT ANSWER
Start with the inputs you can verify
Effective PPI equals source pixels divided by the placed size in inches. Check both axes and compare the smaller value with the printer’s current specification rather than assuming one universal target.
Use placed size
A high-pixel image can still have low effective PPI when enlarged. Measure its intended placed size, including any crop or scaling applied in the layout.
Effective PPI = source pixels ÷ placed size in inchesPreflight the output
Inspect the exported PDF and proof at the final process. Resolution is one check among color, transparency, bleed, fonts, and finishing requirements.
A practical workflow
- Record source pixels.
- Record placed width and height.
- Calculate PPI on both axes.
- Compare with the printer specification and preflight the final PDF.
Sources and further reading
Use these primary references with the current supplier, carrier, machine, or production specification that governs your job.
- Image resolutionAdobe