What resolution should you scan old photos at?
Scan resolution decides how much detail you keep. Here are the figures commonly recommended, by print size and by what you want to do with the photo, without bloating your files for nothing.
What resolution should you scan an old photo at?
As a common rule of thumb, 300 dpi is enough for a print you will reprint at the same size, and 600 dpi is recommended for archiving or enlarging. These are customary figures, not a hard rule.
The right setting depends mainly on two things: how big the original is, and how big you want to show or print it afterwards. The smaller the photo, the higher you need to scan to keep enough pixels.
What settings suit each type of photo?
The table below gives the values generally recommended for a flatbed scanner. The arithmetic is simple: a 6×4 inch (10×15 cm) print scanned at 300 dpi gives about 1,800 × 1,200 pixels, and twice that at 600 dpi.
For a phone shot, dpi does not really apply: just fill the screen with the print, as explained in scanning photos with your phone.
| Original | Usual resolution | Why |
|---|---|---|
| 6×4 in (10×15 cm) print or larger | 300 to 600 dpi | enough for a same-size print |
| Small photo (passport, locket) | 600 to 1200 dpi | it will be enlarged |
| Printed postcard | 600 dpi | the printing dot pattern is very fine |
| Large framed portrait | 300 dpi | the size already provides the pixels |
Should you scan at the highest setting available?
No: past a certain point you gain file size, not detail. An old print only holds so much fine detail, and the scanner ends up recording the paper texture rather than the picture.
Very high resolutions make sense for small formats and slides, with a suitable scanner. For an ordinary family print, 600 dpi usually covers every use.
What resolution does online restoration need?
On Souvenotte, a photo of about 1,600 pixels on the long side is enough: larger images are first reduced to that size, then enlarged twice, up to 3,200 pixels at most. A 300 dpi scan of a 6×4 inch print already covers that.
Scanning higher is still worthwhile for your own archive. Uploads accept JPG, PNG or WebP files up to 25 MB; for a small photo, scan high enough that it reaches those dimensions before uploading.
Which file format should you scan to?
For archiving, a lossless format (TIFF or PNG) is the usual choice; for uploading and sharing, a good-quality JPG is fine. Avoid re-saving the same JPG over and over: each save loses a little detail.
Keep the master file untouched and work on copies. Give it a clear name (rough year, place, people) and store it using the method in backing up family photos.
Which scanner settings should you avoid?
Turn off auto-sharpening, heavy descreening and any ‘smart’ colour correction your software switches on by default. They alter the image before restoration and can wipe out detail.
Scan in colour even when the photo is black and white: the file keeps the tone of the paper, and restoration then decides whether to colourise it or not. Clean the scanner glass and lay the print straight.
Frequently asked questions
Is 300 dpi enough for printing?
For a same-size reprint, usually yes. To enlarge, scan at 600 dpi. The Souvenotte Studio warns you when a photo is too small for the chosen size (a guide of about 200 dpi on the short side).
Should a black-and-white photo be scanned in colour?
That is the most common advice: a colour scan keeps the paper's shades (sepia, yellowing). You can always keep it black and white afterwards.
What about a very large photo?
300 dpi is usually enough, since the original's size already gives plenty of pixels. If it does not fit on the scanner glass, photograph it with your phone.