DPI, or dots per inch, controls how much detail a scan captures. Higher DPI can be sharper, but it also creates larger files and slower scans. A quick text document does not need the same setting as an old photo you plan to enlarge.
Does this affect you?
Use this guide if scans are blurry, files are enormous, scanning is slow, or you are unsure whether to choose 150, 300, 600, or 1200 DPI.
Change DPI in the printer scanning app
Manufacturer apps usually expose the most complete scan settings.
- Open HP Smart, Epson Scan, Epson Smart Panel, Canon IJ Scan Utility, Brother iPrint&Scan, or your printer scanning utility.
- Open Scan Settings, Preferences, or the gear icon before scanning.
- Choose 150 to 200 DPI for simple text you only need to read or email.
- Choose 300 DPI for most documents, forms, and general scanning.
- Choose 600 DPI for small print or documents you may zoom into.
- Choose 600 to 1200 DPI for photos, especially small originals you may reprint or enlarge.
- Start the scan and avoid going higher than necessary.
Change DPI in Windows Scan
The built-in Windows app has the same setting in a simpler interface.
- Open the Windows Scan app.
- Select the scanner if more than one is installed.
- Click Show more.
- Change Resolution (DPI) using the same guidance above.
- Use Preview before the final scan when possible.
Change DPI on Mac
Preview and Image Capture both include resolution controls.
- In Preview, choose File > Import from [scanner] and click Show Details.
- Set the Resolution dropdown.
- Or open Image Capture, select the scanner, and change the Resolution field near the bottom.
- Scan after the DPI is set.
More control
DPI grows file size quickly
Doubling DPI roughly quadruples file size because detail increases in both width and height. A 1200 DPI color page can become very large.
Color mode matters
Black-and-white or grayscale creates much smaller files for plain text. Use color only when color carries information or for photos.
OCR works well around 300 DPI
For searchable or editable text, 300 DPI is usually the best balance. Much higher settings rarely improve OCR enough to justify the file size.
Sources
- Microsoft Support – Scan a Document or Picture in Windows (2025)
- Apple Support – Import Images Using Preview on Mac (2025)
- Epson Support – Scan Resolution and Image Type Settings (2025)