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What are the Different Versions of PDF/A?

PDF/A has become the source of reserving important PDF documents for future use. With the advancement in technology, it seems a fairer task to take hold of essential PDF documents so that at any time in the future, you can access them irrespective of the software you are accessing.

This article will discuss various PDF/A versions and how they can help secure essential PDF documents for the future.

Part 1. What is PDF/A?

PDF/A is one of the branches of PDF file format that saves all of the information of a PDF document, such as the font and other elements. This feature of PDF/A makes it an ideal solution to secure and preserve essential PDF documents so that they can be traced back quickly in the same manner.

The PDF/A files offer lifetime access to the data stored on them and ensure the same quality of data, such as the color, fonts, vector graphics, text, and alignment. Besides this, PDF/A files can be accessed on any device, software, and operating system.

Part 2. What’s the Distinction between PDF and PDF/A?

There is a notable difference between the PDF and PDF/A file formats. The PDF/A file format doesn't support graphical elements such as audio and video files. On the other hand, PDF documents allow users to store audio and video files.

Secondly, users can not add any password or restriction in a PDF/A format. However, on the other hand, PDF files can be password protected. Besides, external links, URLs, and external references are not supported by PDF/A documents as it creates chances of the corruption of a PDF/A document while opening it. On the other hand, the PDF format doesn't restrict users from adding external or third-party links.

Part 3. What are the PDF/A Standards and Conformance Levels?

PDF/A offers different standards as technology is always enhancing and working towards providing the best, most reliable, and most secure file archiving method. With different standards available, everyone offers different features to its users along with contrasting conformance levels. Discussed below are 4 different standards and conformance levels different PDF/A version offers:

1. PDF/A-1: (ISO 19005-1:2005)

PDF/A-1 is based on the original PDF/A standard based on PDF 1.4, which was published in 2005. It is one of the standards which offers extensive restrictions, yet it is mainly used standard of PDF/A format. Being one of the oldest PDF/A standards, it provides some restrictions to the users, such as JPEG 2000 is not supported by it. Besides this, attachments and layers in a document were also not recognized by PDF/A-1. PDF/A-1 offers the conformance level of “a” and “b."

2. PDF/A-2: (ISO 19005-2:2011)

PDF/A-2 was based on PDF 1.7 and was published in 2011. This standard of PDF/A offers a better feature than the last one as users were now allowed to add layers and attachments as well. It also provided a better file compression feature than JPEG 2000 and JBIG2, which are helpful for scanned documents. However, the publication of a new standard doesn't outdate the latter.

To switch to upcoming standards of a PDF/A format, users were required to validate their files from the software as a standard PDF/A-1 format. Another conformance level was also unlocked with the PDF/A-2 called “u," which allows users to search and extract the text. It also offers to reproduce the same copy of the pages of a PDF/A-2 document.

3. PDF/A-3 (ISO 19005-3:2012)

2012 comes with another standard of PDF/A format being published named PDF/A-3 based on PDF 1.7. PDF/A-3 allows users to attach arbitrary files in a PDF/A-3 as an attachment. PDF/A-3 supports the conformance level of the prior PDF/A standards such as "a," "b," and "u."

PDF/A-3 offered an improved version in which embedded formats could be read easily using machine-reading XML data to further enhance the capabilities of an attachment than mere extraction of data. This standard was highly appreciated by Factur-X as assistance in their invoice system.

4. PDF/A-4 (ISO 19005-4:2019)

PDF/A-4 comes next in the line of PDF/A standards published in 2020 and based on PDF 2.0. The conformance levels of other PDF/A standards were confusing as every standard uses mixed conformance levels are users were confused about finding a perfect match based on their requirements. However, PDF/A-4 comes with its conformance levels "e" and "f."

PDF/A-4 also allows users to embed rich media files and 3D content, which are highly helpful for the engineering sectors such as construction and other workflow related to the field.

Part 4. What are the Differences between these PDF/A Conformance Levels?

A different version of a PDF/A format supports different features, which are categorized under different levels called conformance levels.

Level b (Basic)

PDF/A-1b, PDF/A-2b, PDF/A-3b

Level b (as in basic) conformance ensures that the document offers users to view files effortlessly and the visual element of the documents are saved securely for a longer period.

Level a (Accessible)

PDF/A-1a, PDF/A-2a, PDF/A-3a

Level a (as inaccessible) is a subset of conformance b and stores the information with regard to structure and semantic code in a PDF/A format. Besides ensuring the visual quality of data, level a makes it easier to understand, search and copy the elements on a PDF/A file, especially for impaired viewers.  

Level u (Unicode)

PDF/A-2u, PDF/A-3u

Level u (as in Unicode) is just like level "a"; the character mapping of Unicode is also essential. However, specific requirements, such as tags in a PDF/A file, are not necessary for this conformance. Level u allows viewers to search and copy elements from a PDF/A document readily with no reading order guaranteed.

Part 5. How to Convert PDF to PDF/A?

UPDF offers a most effortless and seamless PDF editing experience to its users. Its simple and modern user interface makes it easier for users to explore and apply different features to their PDF documents. UPDF offers a complete solution, from editing a PDF document to converting a document into other formats. Besides this, it allows users to annotate their notes and organize PDF documents on the go with dedicated features.

Following the conversion feature, users can also convert a PDF document into PDF/A format to secure the file's content for future use. You can download UPDF to learn the following steps step by step.

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Steps to Convert PDF to PDF/A with UPDF

Follow the steps mentioned below to convert a PDF document into a PDF/A format with the help of the conversion feature on UPDF:

Step 1: Open PDF in UPDF

Firstly, download a UPDF on your computer. Launch UPDF and import a PDF document by clicking "Open File." You can also import a PDF document using the drag and drop option.

Step 2: Click on PDF/A Conversion

Navigate to the right panel and click on the PDF/A conversion tool. To initiate the process, click on "Save as PDF/A."

Step 3: Save the Changes

After converting your PDF document to PDF/A, rename the document, select the destination, and click on save.


PDF/A documents help you save and secure essential data for archiving purposes so that you can easily retrieve data in the future. However, it is highly important to use software that offers a reliable and secure conversion, such as UPDF, which converts a PDF document into PDF/A format in three simple steps. Next time you are required to convert your PDF document, try the effortless experience of conversion offered by UPDF.

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