How to Remove Duplicate Photos? Misreading EXIF Timestamps Prevention

As a Mac user, you can often meet the need to delete duplicates to free up storage on your device. It’s particularly common to delete unnecessary duplicate photos with special scanning tools. Such software offers much faster deletion compared to checking your folders and removing images manually.

Can originals be automatically deleted instead of duplicates? Unfortunately, the answer is yes. Such accidental photo erasure is often linked to the software misreading EXIF timestamps. Learn how to remove duplicate photos without risking the original images.

How Do Duplicate Photo Scanners Work?

To delete a duplicate photo, the software must identify the given file as such. The criteria used include size, resolution, or date. They also often flag the image with the highest resolution as original.

Main decision criteria include:

• Resolution
• File size
• EXIF date
• Folder path
• Name pattern

Though the criteria used may vary by app, they all follow a similar algorithm. First, they group files by content hash or similarity. Then they autoselect duplicate files or use the “keep one per group” rule. 

What is EXIF?

Exchangeable Image File Format (EXIF) is a standard for embedding metadata in digital image files (JPEG and TIFF). It tracks technical details from capture. Duplicate scanners often rely on EXIF dates to identify identical files.

EXIF embeds:

• TimeStamps: DateTimeOriginal, CreateDate, ModifyDate.
• Location: GPS coordinates.
• Image-specific data: Resolution, color space, thumbnail, file size.

How Does EXIF Misreading Happen?

Let’s dive into the possible scenarios of EXIF misreading. The duplicate scanner can occasionally rely on incorrect metadata. Thus, instead of using content analysis, it detects identical DateTimeOriginal, mistakenly flagging unique files as duplicates.

Typical scenarios for EXIF misreading:

• Camera clock errors (incorrect timestamps)
• Lack of proper EXIF in scanned images
• Exporting photos from social media
• Software conflicts (edits of DateTimeOriginal)

4 Tips to Prevent EXIF Misreading

The key to preventing EXIF misreading is proactive metadata verification. It ensures the duplicate scanner won’t flag the files as false duplicates.

1. Verify Exif metadata

Before you launch the duplicate scanner, inspect EXIF. You can use a special tool, like ExifTool by Phill Harvey, to reveal metadata. Use the command“exiftool-Time:All -G1 -r /path/to/photos” to identify any metadata discrepancies and detect EXIF anomalies.

2. Correct metadata

Use ExifTool to edit EXIF to prevent accidental deletion of originals. Here’s a brief summary of useful commands.

ExifTool Command	Function
exiftool -DateTimeOriginal=”YYYY:MM:DD HH:MM:SS” -overwrite_original DIR	to embed accurate shoot dates
exiftool ‘-FileName<DateTimeOriginal’ -d “%Y%m%d_%H%M%S%%-c.%%e” DIR	to sync data names

3. Configure scanners

Choose duplicate scanning tools that support perceptual hashing. Popular options are dupeGuru and PhotoSweeper. Instead of using EXIF or date sorting, modify their settings to rely on resolution, size, or earlier path. Enable “Preview Mode” if the scanner allows it to do so, and review the file group manually before deletion.

4. Adjust your workflow

The following workflow practices represent the most effective methods to stop users from accidentally deleting their original files.

• You need to verify that your camera clock and time zone settings match the correct values.
• Users should maintain EXIF data during the process of downloading social media photos.
• Don’t rely on metadata alone, and rename photos.

How to Remove Duplicate Photos Safely

You can minimize your chances of accidentally removing unique original files if you stick to the proper algorithm of scanning and deleting duplicates.

1. Back up your data

Before you scan and delete duplicates, ensure critical files are backed up properly. macOS users can opt for Time Machine as a safe and reliable backup tool. Other options are iCloud or third-party backup solutions.

2. Use reliable duplicate scanners

Choose software that prioritizes perceptual hashing over EXIF. The preview option for grouped duplicates is another practical feature. DupeGuru or Duplicate Cleaner enables users to set “keep highest resolution” or “earliest path” and reduce the likelihood of accidental deletion of original photos.

3. Monitor scanning and deletion

Don’t rely on automatic deletion only. When the scan is over, review the file groups, manually select deletion, and choose to delete files by size or file path rather than EXIF data. Perform another scan of cleaned folders, spot-check EXIF with ExifTool. It will help you confirm no unique files were lost.

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Wrap Up

Many duplicate scanners use EXIF to identify identical files and remove unneeded duplicates. This can result in accidental deletion of original photos that occur when metadata is faulty. To prevent such cases of data loss, opt for duplicate scanners that prioritize content-related analysis (size, resolution) over EXIF.