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Digital Preservation Challenges: Why METS and ALTO Are Essential for Large-Scale Archival Projects

Published: 11 Jul 2025

Imagine discovering a centuries-old manuscript, brittle and broken at the edges. Now imagine being tasked to digitize and add it to your library’s collection—not just as a scanned image but as a fully searchable and preserved digital asset. That’s the kind of challenge libraries and archives worldwide face as they move from print to pixels.

These digital preservation initiatives are sometimes large scale, running into several years because it isn’t simply scanning. Without proper structuring, metadata, and text encoding, digital collections risk becoming unsearchable, unusable, or even obsolete. That’s where METS (Metadata Encoding & Transmission Standard) and ALTO (Analyzed Layout and Text Object) come in.

The Scale of the Challenge: Libraries as Data Giants
Major libraries and archives house millions—sometimes hundreds of millions—of items, with ongoing digitization efforts processing thousands of pages daily. Large-scale projects require more than high-resolution scans—they need interoperability, structured metadata, and full-text accuracy for users to meaningfully engage with the content.

Here’s the problem:

A simple image-based digital archive lacks context. A TIFF scan of a rare book is just a picture unless it’s properly indexed.
Poor OCR (Optical Character Recognition) results mean users can’t search the text accurately—especially in historical or non-Latin scripts.
If metadata isn’t standardized, collections become data silos, limiting interoperability across institutions.

METS: Bringing Structure to Digital Archives

METS is like a blueprint for digital objects. Instead of just storing a document, METS binds together multiple components—images, OCR text, metadata, and structural relationships—ensuring that a digitized book or newspaper is more than just a stack of files.

Why METS Matters:
Structural Mapping – Defines the order of pages, chapters, or multi-volume works.
Preservation Metadata – Ensures long-term digital viability by tracking technical details and provenance.
Interoperability – Enables seamless exchange across repositories (Europeana, HathiTrust, DPLA, ProQuest, JSTOR).

Think of METS as a librarian’s guide for the digital world—a way to organize and ensure long-term usability of complex digitized collections.

Why ALTO is the Unsung Hero of Searchability

OCR alone isn’t enough. Standard OCR might extract text, but it loses layout details—crucial for newspapers, tables, and manuscripts. ALTO fixes that.

What ALTO Does Differently:

Retains Text Layout – Captures columns, footnotes, and even marginalia, making digitized newspapers or periodicals look like their physical counterparts.
Improves Search Accuracy – Maps text positions to original layouts, reducing OCR errors.
Supports Multilingual & Historical Texts – Handles complex scripts, Fraktur fonts, and even handwritten materials.

Example: As the Exclusive Partner for ProQuest’s Historical Newspapers Program (HNP) since 2001, we have digitized iconic publications like The New York Times, The Wall Street Journal, and many more. Using METS/ALTO, we have structured 28 million pages across 55 newspaper titles—some dating back to 1764—ensuring that every article, photograph, and advertisement is fully searchable and meticulously preserved. Our solutions not only safeguard history but also create revenue opportunities through content distribution and digital accessibility across tablets, smartphones, and emerging platforms.

Fun Fact: Digital Archives Are at Risk—Even Digital Ones!

Did you know that NASA lost the original high-resolution recordings of the 1969 moon landing? The tapes were overwritten due to poor archival practices. Digital doesn’t always mean permanent—without proper structuring (like METS/ALTO), even digital archives can disappear over time.

Future-Proofing Archives with METS & ALTO

In an era where digital libraries are growing exponentially, METS and ALTO are non-negotiable. They make sure that today’s digitization efforts remain accessible and meaningful for decades—even centuries—to come.

For libraries, archives, and cultural institutions, the choice is clear: Digitize, but do it right.

Ninestars: Bringing Structure to Digital Archives

At Ninestars, we go beyond digitization—we ensure archives are structured, searchable, and future-proof. Our solutions include AOTM OCR, indexing, and metadata enrichment to enhance content discoverability.

With METS, ALTO, MARC, and Dublin Core-compliant workflows, we’ve digitized 1.2 billion pages to date, making vast collections accessible across libraries, enterprises, and institutions. Our expertise spans subject- and keyword-based indexing, AI-powered OCR for handwritten texts, and contextual OCR in 71 languages for unmatched accuracy.

From national archives to rare manuscripts, we help organizations preserve history while unlocking new revenue and digital opportunities. Let’s talk.