How to Scan Old Photos Properly: DPI, Cleaning Prints Safely and File Formats

Every restoration and every backup starts with a scan. A good one captures all the detail the original holds and gives you a faithful master to work from for decades. A rushed one, at low resolution, saved as a compressed JPEG with the scanner’s auto-fixes turned on, puts a ceiling on everything you do afterwards.

Here’s how to scan old photos properly, from cleaning to settings to file naming.

What you need

• A flatbed scanner for prints. Most consumer flatbeds from the last decade scan prints at 600 DPI or more with real optical resolution, which is all you need.
• A film scanner or a flatbed with a transparency adapter for negatives and slides. Prints are reflective; film needs light shining through it.
• A soft microfiber cloth, a rubber hand blower and a soft brush (an anti-static brush or a clean, soft makeup or lens brush).
• Nitrile or lint-free cotton gloves, optional but helpful.

Phone apps that photograph prints, such as Google PhotoScan, are a reasonable option for quick shareable copies, especially for prints stuck in albums. For an archival master, a flatbed scanner gives more consistent and detailed results.

Step 1: Clean the scanner, not just the photos

Dust on the glass shows up on every single scan. Before a session:

1. Spray a little glass cleaner onto the microfiber cloth, never directly onto the glass, where liquid can seep under the edges.
2. Wipe the glass, then buff it dry with a clean section of cloth.
3. Check for streaks by looking at the glass at an angle against a light.
4. Wipe the white underside of the lid too.

Recheck the glass every twenty or so scans. Fibers from prints and sleeves build up quickly.

Step 2: Clean prints gently and dry

Old prints are fragile. The image sits in a thin layer of gelatin emulsion that scratches, absorbs moisture and reacts to chemicals.

Do:

• Hold prints by the edges.
• Remove loose dust with a hand blower or a soft brush, brushing gently in one direction.
• Use a lightly dry microfiber cloth only on prints that are clearly sturdy and not flaking.

Don’t:

• Use water, alcohol, glass cleaner or any solvent on the print surface.
• Rub at stuck-on dirt or stains. Scan them as they are and fix them digitally.
• Use compressed air from a can, which can spray propellant onto the print.
• Try to flatten curled or brittle prints by force. Scan curled prints gently weighted by the lid, or photograph them instead.

Prints stuck in old “magnetic” self-adhesive albums are a special case. If they don’t lift easily, scan the whole album page rather than peeling them, and consult a conservator for anything important.

Step 3: Choose the right resolution

DPI (dots per inch, strictly PPI for scanners) determines how much detail you capture. Higher isn’t always better: past the detail the original actually holds, you only get bigger files.

Original	Recommended	Use higher if…
Prints 4×6 in (10×15 cm) and larger	600 DPI	You’ll make big enlargements
Small prints, wallet sizes, contact prints	1200 DPI	The print is tiny and very detailed
Large prints (8×10 in and up)	300–400 DPI	Rarely needed
35 mm negatives and slides	2400–4000 DPI	Your scanner’s true optical resolution allows it
Medium format negatives	1600–2400 DPI	You want maximum detail

A simple way to think about it: multiply the print’s size in inches by the DPI to get pixel dimensions. A 6×4 inch print at 600 DPI becomes 3600×2400 pixels, around 8.6 megapixels. That’s enough to reprint it at the same size or a little larger without loss.

Always use the scanner’s optical resolution. “Interpolated” or “enhanced” resolutions just upscale the image in software.

Step 4: Set color and bit depth

• Color mode: scan black-and-white prints in color, not grayscale. Old monochrome prints have warm or cool tones, and the color channels give you more data for removing stains later. You can convert to grayscale afterwards.
• Bit depth: if your software offers 48-bit color (16 bits per channel), use it for your masters, especially for faded or high-contrast originals. It gives much more room for correcting tones without banding.
• Auto corrections: turn off auto color, auto exposure, sharpening, descreen (unless scanning printed magazine images), and grain reduction. You want a neutral, faithful master.
• Dust removal: infrared-based dust removal (such as Digital ICE) is useful for color film and slides, but it doesn’t work properly with traditional silver-based black-and-white film. Keep a version without it if you’re unsure.

Step 5: Pick a file format

Format	Compression	Use for
TIFF	Lossless (none, LZW or ZIP)	Archival masters, editing
PNG	Lossless	Masters if TIFF isn’t available (8- or 16-bit)
JPEG	Lossy	Sharing, email, web, quick prints
HEIC	Lossy	Phone storage; avoid for masters

Save the master as TIFF with LZW or ZIP compression. These are lossless and reduce file size without discarding any information. Export JPEGs from the master when you need to share. Re-saving a JPEG repeatedly degrades it each time; re-saving a TIFF doesn’t.

Step 6: Scan in batches without cutting corners

Scanning several prints at once and letting the software split them saves time. Leave a gap of at least a centimeter between prints and from the glass edges so auto-crop can detect them. Check each split file, because auto-crop sometimes trims borders or merges two prints.

Scan the back of a print if it has handwriting, a date, a studio stamp or a processing lab mark. Those details are often the only record of who, where and when. Name the back scan to match the front:

1958-07_wedding_rosa-and-tom_001.tif
1958-07_wedding_rosa-and-tom_001_back.tif

Starting file names with the year (and month if known) sorts your archive chronologically in any file browser.

Step 7: Record what you know

While a relative is around to identify faces and places, write it down. You can:

• add captions, people and locations to the file’s metadata (IPTC/XMP fields) in apps like Adobe Bridge, Lightroom, digiKam or many photo managers;
• keep a simple spreadsheet or text file next to the scans, keyed by file name.

Metadata stored inside the file travels with it; a sidecar file is easier to edit. Doing both is ideal.

Step 8: Then clean up and back up

Once you have clean masters, you can work on copies: removing dust, repairing scratches and fixing faded colors, as covered in our guide to restoring old damaged photos. Tools like DirtAI aim to make the dust and scratch stage fast: brush over the damage, and the AI fills it in naturally, leaving your master scan untouched.

Before doing anything else, though, back the masters up. A day of careful scanning shouldn’t depend on a single drive. Our 3-2-1 backup guide for family photo archives explains a simple routine.

Quick checklist

• Clean the scanner glass with a cloth, not a spray.
• Blow and brush prints dry; no liquids on the surface.
• 600 DPI for prints, 1200 for small ones, 2400+ for film.
• Color mode, 48-bit if available, auto-fixes off.
• Save TIFF masters; export JPEGs to share.
• Scan the backs, name files by date, record who and where.
• Back up before you edit.