PDF/A is a type of PDF file format that is similar to the normal PDF file formats you know but with a different set of standards and conformance. This file format is meant to allow interoperability across different platforms, systems, and computers with the aim of making PDF/A files accessible even in future. This file format looks to make PDF/A documents not vulnerable to time restrictions that other file formats undergo when standards change and new technologies are introduced in the market. PDF/A file format comes with a lot of standards and conformance levels of its own and in this article, I am going to take a look at them.
There are several variants of PDF/A, which are made by combining different PDF/A conformance levels and standards. Each standard provides a definition of available features and technologies for compressing images that are used to help in preserving contents of a file. Each standard supports different conformance levels. What conformance levels do is that they control accessibility, impacting how contents of a file are understood by people and machines.
PDF/A file can also be converted to other file formats such as word. As a result, you can use a PDF to word converter to make the switch easily.
PDF/A-1: (ISO 19005-1:2005)
PDF/A-1 refers to the original PDF/A standard and is the most commonly used standard at the moment. However, it is also the most restrictive. This standard is based on an even older version of PDF standard, PDF 1.4 which was first published in the year 2001. As a result, this standard is not able to support JPEG 2000 attachments and layers. Even though PDF 1.4 supports transparency, it was not included in PDF/A-1 because it was thought at the time be a very new idea. Conformance levels for this PDF format are a and b.
PDF/A-2: (ISO 19005-2:2011)
PDF/A-2 was introduced in the year 2008 and it is based on PDF 1.7. There are several features introduced in this variant of PDF that were not available in PDF 1.4. Some of the additions included are enhanced image compression capability, layers, and attachments. However, the attachments in the document have to be in PDF/A format. The introduction of PDF/A-2 doesn’t render PDF/A-1 obsolete, but rather is intended to be forward compatible.
This file format uses conformance level u, which allows it to be reliably searched and copied.
PDF/A-3 (ISO 19005-3:2012) and PDF/A-4 (ISO 19005-4:2019)
The level of similarity between PDF/A-3 and PDF/A-2 is very high. Even the typos that are found in PDF/A-2 still exist in PDF/A-3. The main difference between these two file formats is that PDF/A-3 works with all types of attachments. The conformance levels for this file format are a, b, and u and it is based on PDF 1.7.
PDF/A-4 was introduced in 2019 and is simply an iteration of PDF/A-1. This PDF file format is based on PDF 2.0 and comes with two new levels of conformance, that is, e and f. It introduces TBD as a new feature.