Keeping Scanned Documents Readable for Decades: File Formats and Habits

How to make sure the documents you scan today can still be opened in ten or twenty years, through sensible formats, backups and periodic checks.

Paper can last a century in a drawer. A digital file can be lost in seconds, or become unreadable when technology changes. If you're scanning documents that matter for the long term, a few habits protect them.

Choose widely supported formats

PDF is the most widely supported format for documents, and is likely to remain readable for a very long time.
JPEG is universal for photographs.
PNG and TIFF are lossless formats sometimes used for archives.

Avoid obscure or proprietary formats for anything you want to keep long-term.

Archival PDF

There's a specialised version of PDF, called PDF/A (ISO 19005), designed for long-term archiving. It embeds everything needed to display the file, and forbids features that might stop working. Libraries and government archives use it. For home use, a normal PDF is usually sufficient, but PDF/A is worth knowing about if you have a very large collection or professional needs.

Keep a high-quality master

Scan important documents at good quality, and keep an unaltered master. Make compressed copies for sharing, but keep the master untouched.

Back up in more than one place

The 3-2-1 rule is a good guide:

3 copies of the file,
on 2 different kinds of storage, such as a phone and a hard drive,
with 1 copy off-site, such as cloud storage or a relative's house.

Check your backups

Backups that have never been opened are backups you can't trust. Once or twice a year, open a few files from your backup to check they work.

Refresh storage

Hard drives and memory cards don't last forever. Consider copying your archive to new storage every few years, especially if the old device begins to show problems.

Keep names and folders clear

Files with clear names and a logical folder structure will still make sense to you, or to family members, in twenty years. Include a short "readme" note in the main folder explaining how things are organised.

Protect against accidental change

Once a document is finished, such as a signed contract, avoid editing the master. Keep a "final" folder for files that shouldn't change.

Passwords and encryption

Password-protected files are safe, but you must not forget the password. Store passwords in a secure password manager, and let a trusted person know how to find them in an emergency.

Keep paper originals when required

For some documents, such as birth certificates, property deeds and wills, the original paper may be legally required. A scan is a backup and a convenience, not always a replacement.

Digital estate

Consider how your family could reach your important documents if something happened to you: where they're stored, and how to open them.

Checklist

PDF for documents, JPEG for photos.
High-quality master saved.
Three copies, two media, one off-site.
Backups tested regularly.
Storage refreshed every few years.
Originals kept where required.

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