What dpi should you scan photos, negatives and slides at?
The right scan resolution depends on how big the original is and how big you want to print it. A 35mm negative is only 36 × 24 mm, so it must be scanned at a much higher dpi than a 6 × 4 in print. Choose your original, the print size you want and your scanner in the guide below, and it shows the dpi to scan at, the size of the resulting file and whether your scanner can really deliver that detail. The table shows the scan resolution needed for a sharp 300 ppi print. If you would rather have it done for you, see my photo, slide and negative scanning and photo printing services.
| Original | 10 × 8 in print | A4 print | A3 print | A2 print |
|---|---|---|---|---|
| 35mm film (36 × 24 mm) | 2540 dpi | 2630 dpi | 3710 dpi | 5250 dpi |
| 120 film 6 × 4.5 (56 × 41.5 mm) | 1470 dpi | 1590 dpi | 2250 dpi | 3180 dpi |
| 120 film 6 × 6 (56 × 56 mm) | 1360 dpi | 1590 dpi | 2250 dpi | 3180 dpi |
| 120 film 6 × 7 (56 × 70 mm) | 1090 dpi | 1270 dpi | 1800 dpi | 2550 dpi |
| Sheet film 4 × 5 in | 600 dpi | 700 dpi | 990 dpi | 1400 dpi |
| 6 × 4 in print | 600 dpi | 620 dpi | 880 dpi | 1240 dpi |
Scanning questions
What dpi should I scan 35mm negatives at?
For a sharp A4 print at 300 ppi, scan 35mm film at about 2,600 dpi. For A3 you need about 3,700 dpi. For a 6 × 4 in print about 1,300 dpi is enough.
What dpi should I scan old prints at?
To make a copy at the same size scan at 300 dpi. To enlarge a 6 × 4 in print to A4 scan at about 620 dpi. Scanning prints above 1,200 dpi rarely adds detail, because the detail in the paper and the print itself is the limit.
Does a higher dpi always give a better scan?
No. Every scanner has a real limit to the detail it can resolve, which is often much lower than the number on the box. A flatbed scanner such as the Epson V600 is usually reported to resolve roughly 2,400 dpi of real detail on 35mm film, so scanning at 6,400 dpi mainly makes bigger files. Dust, film flatness and focus often matter more than the dpi setting.
How big will the scan files be?
A 35mm negative scanned at 3,200 dpi is about 4,500 × 3,000 pixels, around 14 megapixels. As an uncompressed 16-bit TIFF that is roughly 82 MB per frame, and a JPEG is much smaller.