The practical DPI guide
- 300 DPI: good for viewing, sharing, and printing at roughly the original physical size.
- 600 DPI: the best default for old family prints that may need restoration, cropping, or a moderate enlargement.
- 1200 DPI: worth testing for wallet photos, contact prints, small studio portraits, and genuinely fine surface detail.
- 2400 DPI and above: usually a film or specialist-capture setting, not a useful default for ordinary paper prints.
DPI, pixels, and print size
DPI describes how many samples the scanner takes across each inch of the physical print. A 6×4-inch photo scanned at 600 DPI becomes about 3600×2400 pixels, or 8.6 megapixels. The same print at 1200 DPI becomes 7200×4800 pixels and four times the pixel count.
Use the free photo scan DPI calculator to calculate dimensions and an approximate uncompressed file size before you scan a whole album.
Settings for a restoration-ready master
- Scan the complete print, including borders, rather than cropping in the scanner.
- Use colour mode even for a black-and-white print so paper tone, stains, and annotations remain available.
- Choose the scanner's true optical resolution; interpolated settings only manufacture extra pixels.
- Turn off automatic sharpening, dust removal, colour restoration, and aggressive contrast for the master.
- Save a lossless TIFF or PNG master, then make separate JPEG and restored copies.
When more DPI does not add detail
A higher number cannot overcome the limits of the original lens, film, paper, focus, or scanner optics. It may record paper texture and dust more precisely without revealing another eyelash or letter.
Scan a meaningful crop at 600 and 1200 DPI, view both at the same physical size, and compare real edges such as hair, fabric weave, and printed lettering. If 1200 DPI adds only noise and file size, use 600.
Common scanning mistakes
- Scanning a black-and-white photograph in one-bit document mode
- Saving the only copy as a heavily compressed JPEG
- Using an automatic feeder for fragile, bent, or valuable prints
- Closing a scanner lid onto an object that does not fit flat
- Deleting the original scan after an edited version looks better
FAQs
Is 600 DPI enough for old photos?
For most 4×6, 5×7, and 8×10 family prints, 600 DPI gives ample pixels for restoration and moderate enlargement.
When should I scan at 1200 DPI?
Use 1200 DPI for very small prints, contact prints, or a source with genuinely fine detail. Run a small test because file size rises quickly and the print may not contain additional detail.
Should black-and-white photos be scanned in colour?
Yes. Colour mode preserves paper tone, stains, annotations, and subtle channel differences that can help later restoration.
Sources
Preservation and technical guidance reviewed for this article.
- U.S. National Archives: Digitizing Family Papers and Photographs
- U.S. National Archives: Digital Photographic Records
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