Film to PhotosWhat DPI should I scan 35 mm film at? (1800 vs 3600)
The right resolution for scanning 35 mm negatives: 3600 dpi for archiving and big prints, 1800 dpi for sharing. Print sizes, file sizes and why 7200 dpi is rarely worth it.
Scan 35 mm negatives at 3600 dpi if you want to keep them forever or print bigger than 8×10 inches, and at 1800 dpi if you just want to share them on screens or make small prints. 3600 dpi gives about 17 megapixels — similar to a good modern camera — and captures essentially all the detail a home film scanner can see.
Quick guide
| Scan setting | Pixels (35 mm frame) | Megapixels | Good for |
|---|---|---|---|
| 1200 dpi | 1700 × 1130 | 2 MP | Phone screens, 4×6 prints |
| 1800 dpi | 2550 × 1700 | 4 MP | Sharing, slideshows, prints up to 8×10 in |
| 3600 dpi | 5100 × 3400 | 17 MP | Archiving, cropping, prints up to about 12×18 in |
| 7200 dpi | 10200 × 6800 | 69 MP | Rarely useful: bigger files, not more detail |
A 35 mm frame is about 36 × 24 mm (1.42 × 0.94 inches). Multiply those inches by the dpi and you get the pixel size.
What we recommend
- Family archive: 3600 dpi. You only want to handle old negatives once.
- Quick look at a box of old negatives: 1800 dpi, then rescan the keepers at 3600.
- Huge enlargements: 3600 dpi is still the right setting on a home scanner; for poster sizes, scan carefully and use upscaling software later rather than 7200 dpi.
In Film to Photos these are simply Archive (3600 dpi) and Quick (1800 dpi).
Why 7200 dpi doesn't add detail
Plustek OpticFilm scanners advertise 7200 dpi, but independent reviews (for example on filmscanner.info) measure roughly 3,500–4,000 dpi of real detail. Above that you're mostly magnifying the blur of the scanner's lens and the film's grain. Most snapshot cameras and consumer films didn't record much more than that either. The cost is real: a 7200 dpi scan takes several times longer and the file is four times bigger.
How big can I print?
Photo labs print sharp at about 300 pixels per inch; 200 is still good for big prints viewed from a step back.
| Scan setting | Sharp print (300 ppi) | Good print (200 ppi) |
|---|---|---|
| 1800 dpi | 5.7 × 8.5 in | 8.5 × 12.7 in |
| 3600 dpi | 11.3 × 17 in | 17 × 25 in |
More detail, including 4×6, 5×7, 8×10 and poster sizes, in What DPI to scan negatives for prints.
File size matters too
| Scan setting | 16-bit TIFF | High-quality JPEG |
|---|---|---|
| 1800 dpi | about 26 MB | about 1–3 MB |
| 3600 dpi | about 100 MB | about 5–10 MB |
A 36-exposure roll at 3600 dpi as 16-bit TIFF is about 3.6 GB. Save JPEG copies for sharing and keep TIFFs or the original scans for archiving; see TIFF or JPEG?
What about other film sizes?
Bigger film needs fewer dpi for the same print. A 6×6 cm medium format (120) negative at 2400 dpi already gives about 5300 × 5300 pixels. Plustek OpticFilm scanners only take 35 mm film; see what kind of film do I have?
Quick answers
What is the best DPI for scanning 35 mm negatives?
3600 dpi for archiving and large prints (about 17 megapixels); 1800 dpi for sharing and prints up to about 8×10 inches (about 4 megapixels).
Is 7200 dpi worth it on a Plustek scanner?
Rarely. Independent tests of Plustek OpticFilm scanners measure roughly 3,500–4,000 dpi of real detail even at the 7200 setting, so 7200 dpi mostly gives four times bigger files and much slower scans.
How big is a 3600 dpi scan of 35 mm film?
About 5100 × 3400 pixels (17 megapixels). As a 16-bit TIFF that's roughly 100 MB per frame; as a high-quality JPEG about 5–10 MB.
What DPI do I need to print a 4×6 from a negative?
About 1200 dpi gives a good 4×6 (around 280 pixels per inch). Scan at 1800 dpi if you might crop, and 3600 dpi if you might ever print bigger.
Is DPI the same as PPI?
For scanning, people use them interchangeably: both mean how many pixels the scanner records per inch of film.