What is PDF/A? Why It Matters & How To Use It

Portable Document Format Archive (PDF/A) is an ISO-standardized file format designed for the long-term preservation of electronic documents. Unlike standard PDFs, PDF/A files are self-contained, embedding all fonts, color profiles, and metadata, so a document’s visual appearance remains consistent over time, even as software and hardware evolve. 

People frequently switch devices, update applications, and adopt new tools. Without proper preservation, PDFs can lose formatting, fonts, or metadata, creating accessibility and compliance issues. 

By creating PDF/A documents now, you can future-proof your files, ensure consistent rendering, and save time on corrections later.

This guide answers the most common questions about PDF/A, from its purpose to practical usage tips.

1. What is PDF/A and how does it work?
2. Why should I convert my documents to PDF/A?
3. How are PDF/A files used?
4. What are the different types of PDF/A?

1. What is PDF/A?

Portable Document Format Archive (PDF/A) is a specialized PDF format designed to preserve the exact appearance of your documents over the long term.

By requiring all fonts, color profiles, and metadata to be embedded, PDF/A ensures your documents

2. Why should I convert my documents to PDF/A?

Converting documents like contracts, technical manuals, or research reports to PDF/A offers significant long-term accessibility benefits, including:

• Consistency: Your documents will appear the same way they were created, regardless of software or hardware changes over time. 
• Searchability: PDF/A documents can be indexed and searched, enhancing their accessibility for future retrieval and reference. 
• Legal compliance: Many industries require the use of PDF/A for archiving to ensure legal compliance and document authenticity. 
• Accessibility: PDF/A standards include accessibility features, making documents inclusive for individuals with disabilities. 
• Reduced risk: By archiving documents in PDF/A format, organizations can reduce the risk of data loss, ensuring business continuity and compliance.

3. How are PDF/A files used?

PDF/A files are used wherever document longevity, consistency, and compliance are required.

Common use cases for PDF/A include:

4. Are there different types of PDF/A?

PDF/A has evolved through several standards (PDF/A-1, 2, 3, 4), mixing different conformance levels to accommodate advancements in technology, compression, and embedded file types.

PDF/A-1

This is the most used and original PDF/A standard which ensures the visual appearance of the document is preserved over time. It is also the most restrictive as it doesn’t support JPEG 2000, layers or attachments.

Missing features: JPEG2000, transparency, layers, and attachments

Conformance levels:

1. PDF/A-1a (Accessible) allows assisted technologies to improve accessibility of a PDF by providing text and other elements in an accessible format. This allows all users to access information. An example of how PDF/A-1a can be used is through a screen reader for the visually impaired. 
2. PDF/A-1b (Basic) is used to create archival versions of documents so they can be rendered the same as when they were saved. It is a stricter subset of the ISO PDF specification. 

Learn how to convert PDF to PDF/A in our user guide.

PDF/A-2

PDF/A-2 builds on PDF/A-1 by providing additional support for color spaces, JPEG2000 compression and embedded files and introducing transparency. PDF/A-2 doesn’t make PDF/A 1 obsolete which means a valid PDF/A-1b file can pass verification on software set to validate PDF/A2b or PDF/A-3b.

New features: JPEG2000, transparency, layers, and attachments (only other PDF/A files)

Conformance levels:

1. PDF/A-2a (Accessible) builds on the structure that was formed by PDF/A-2u tags, making searching and reusing contents of a PDF document easier. Similar to PDF/A-1, it makes documents accessible to those with visual impairments.
2. PDF/A-2b (Basic) is the minimal compliance needed to ensure a PDF document can be visually rendered the same as when it was created.
3. PDF/A-2u (Unicode) includes all of Level B conformance with an additional requirement that all text in the document have Unicode equivalents, ensuring that all text can be indexed and displayed. 

Learn how to convert PDF to PDF/A-2a, 2b & 2u in our user guide.

PDF/A-3

PDF/A-3 introduces embedding within a PDF/A file, or files in any other format (not just other PDF/A files as permitted in PDF/A-2), making it suitable for documents that need to include non-PDF attachments.

New features: Attachments (any filetype).

Conformance levels:

1. PDF/A-3a improves accessibility, similar to PDF/A 2a and PDF/A-1a. 
2. It has high visual integrity and ensures the identical display of a PDF document to when it was created. 
3. PDF/A-3u allows the searchability of texts and the copying of Unicode text for digitally created PDF documents and those scanned using optical character recognition (OCR). 

PDF/A-4

PDF/A-4 supports archiving of fillable forms by allowing non-static content in PDF documents in the form of JavaScript. This means that information about the values or logic of an interactive form can be stored and archived. It also simplifies the handling of digital signatures.

New features: 3d models, rich media and 3D annotations.

Conformance levels: 

1. PDF/A-4e (Engineering) supports 3D models, rich media and 3D annotations as well as embedded files.
2. PDF/A-4f allows the embedding of arbitrary files. 

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