Is 300 or 600 dpi better for scanning old photos?

It depends on output and useful detail. A full 4 × 6-inch image captured at 300 dpi produces about 1,200 × 1,800 pixels; at 600 dpi it produces 2,400 × 3,600. Compare pilot scans and choose a supported optical setting for the enlargement and crop you need.

Does scanning at 1,200 dpi always capture more detail?

No. It creates more output pixels, but the original, scanner optics, focus, and software can limit resolved detail. Inspect the saved images at a comparable output size before selecting a very high setting for a large batch.

Why does the calculator show 500 dpi for an 8 × 10 fit?

A full 4 × 6 image fits inside 8 × 10 paper as approximately 6.667 × 10 inches, with side borders. That enlargement needs a calculated 500 ppi capture for a 300 ppi output. Crop to fill needs a different calculation. Select an available optical preset that meets the estimate.

Does the RGB data estimate equal the TIFF file size?

No. It estimates captured pixels multiplied by three bytes for 8-bit RGB. Actual files also depend on bit depth, compression, metadata, previews, and format structure.

Photo Scanning Resolution: DPI and Enlargement Calculator

Updated November 1, 2026 6 min read

Choose photo scanning resolution by the size of the original, the crop you plan to keep, and the size of the new print. For an uncropped 4 × 6-inch paper photo, 300 dpi captures about 1,200 × 1,800 pixels; 600 dpi captures 2,400 × 3,600. At an output target of 300 pixels per inch, the second file has enough pixels for 8 × 12 inches.

That is pixel planning, not a guarantee of visible detail. A blurry original, scanner optics, focus, surface texture, and software interpolation can limit the result. Start with a useful pilot scan and compare saved files before committing the entire collection to a very high setting.

Calculate the photo scanning resolution for your output

Measure the image area you will scan. If you are including a white border that you will later remove, use the retained image area for this planning calculation. Match the original and output orientation, then choose a crop-to-fill or whole-image fit.

Scanner software commonly calls capture density “dpi.” Select an available optical setting that meets the estimate; confirm the device's capabilities rather than assuming any typed value is captured optically. Changing the units selector changes how your entries are interpreted; it does not convert the existing numbers.

The memory figure is calculated as captured width × height × three one-byte RGB channels. It is a planning estimate for uncompressed pixel data in decimal megabytes. TIFF compression, bit depth, metadata, previews, and other file structures change the saved file size.

What 300, 600, and 1,200 dpi produce

Calculated from a full, uncropped 4 × 6-inch image area. Output sizes are pixel-count equivalents at 300 ppi.
Capture setting	Captured pixels	Megapixels	Output size	8-bit RGB pixel data
300 dpi	1,200 × 1,800	2.16 MP	4 × 6 inches	6.48 MB
600 dpi	2,400 × 3,600	8.64 MP	8 × 12 inches	25.92 MB
1,200 dpi	4,800 × 7,200	34.56 MP	16 × 24 inches	103.68 MB

Doubling the capture density doubles each dimension, so pixel count and uncompressed RGB data grow by a factor of four. That is why “always scan at maximum” can create much more data without a matching increase in useful detail.

Epson's scanning guidance gives the same general relationship between enlargement and capture resolution. Software that also asks for a target output size may apply that relationship for you. Check the saved pixel dimensions so you do not unknowingly request the enlargement twice.

Leave room for a different crop

A full 4 × 6 original and an 8 × 10 output have different shapes. To fill the 8 × 10 sheet at 300 ppi, the calculator asks for 600 ppi capture. It captures 2,400 × 3,600 pixels, then the crop uses 2,400 × 3,000 of them. About 16.7% of the full original image area is outside that crop.

If you preserve the whole 4 × 6 composition on the same 8 × 10 paper, a 500 ppi capture gives a 6.667 × 10-inch image at 300 ppi, with centered side borders of about 0.667 inch each. Those are geometry examples. Use the print size and crop guide to inspect the shape change before discarding an important edge.

Check optical resolution and the actual saved file

Optical capture and interpolation are different stages. Interpolation creates additional output pixels from the captured image; it does not establish that the scanner resolved additional fine detail. Epson's explanation of native and interpolated resolution illustrates the distinction. Its historical device figures should not be used as specifications for a current scanner.

When comparing flatbed photo scanners, check the current manual for optical specifications, supported originals, capture modes, and limits in the software you will use. A high resolution in a marketing headline is not enough to choose a working setting.

After scanning, open the file's image properties. Confirm its pixel width and height, color mode, bit depth, and format. A “300 dpi” tag on a 600 × 900-pixel file still contains only 600 × 900 pixels; changing the tag alone does not turn it into a detailed 4 × 6-inch scan.

Run a useful two-setting pilot

Pick an undamaged print with fine detail such as hair, foliage, or lettering. Use the digitizing guide for safe preparation and handling.
Make two captures, for example 300 and 600 dpi, with the same original area and other settings. Record any automatic sharpening or restoration.
Check the saved files at the same intended output size. Comparing only at 100% on screen shows different physical scales when the files have different pixel counts.
Inspect whether the higher setting reveals useful detail, mostly enlarges grain or paper texture, or introduces processing artifacts.
Keep the setting, file dimensions, and observation with the batch record. Repeat the pilot if the original type or scanner changes.

Keep the capture useful after scanning

Keep an untouched master and make separate editing or sharing copies. The Library of Congress scanning guide describes using a TIFF master and JPEG working copies. If a scanner only provides a suitable JPEG, preserve that original capture rather than repeatedly resaving it. A different container cannot recreate detail already lost.

Digitizing a paper print and scanning a film negative are different tasks. A tiny negative intended for a large output requires a different capture and equipment calculation. Do not apply this paper-print workflow to an unknown film type without its handling and scanning guidance.

Finish the batch by checking filenames, useful reverse-side notes, and the number of captured items. Then verify independent backup copies and return the originals to suitable storage.

Sources

The calculator uses proportional enlargement, 1 inch = 2.54 cm, and a chosen output ppi. RGB data estimates use three bytes per pixel.

Frequently Asked Questions

: It depends on output and useful detail. A full 4 × 6-inch image captured at 300 dpi produces about 1,200 × 1,800 pixels; at 600 dpi it produces 2,400 × 3,600. Compare pilot scans and choose a supported optical setting for the enlargement and crop you need.
: No. It creates more output pixels, but the original, scanner optics, focus, and software can limit resolved detail. Inspect the saved images at a comparable output size before selecting a very high setting for a large batch.
: A full 4 × 6 image fits inside 8 × 10 paper as approximately 6.667 × 10 inches, with side borders. That enlargement needs a calculated 500 ppi capture for a 300 ppi output. Crop to fill needs a different calculation. Select an available optical preset that meets the estimate.
: No. It estimates captured pixels multiplied by three bytes for 8-bit RGB. Actual files also depend on bit depth, compression, metadata, previews, and format structure.