The importance of PDF/A for long-term digital archiving

PDF/A is a special type of PDF designed specifically for long-term digital archiving and preservation of electronic documents. In today's digital world, where paper documents are being replaced by digital files, it is crucial to have a method that ensures easy retrieval and display of documents over an extended period of time. In Europe, PDF/A is recommended or even legislated for long-term archiving in various organizations and governments, while in the US, recommendations exist in the fields of jurisdiction and libraries. The main goal of PDF/A is to limit and define technologies in a way that enables the files to be displayed accurately in the distant future, even when using different software.

PDF/A exists in different variants. Each of them is has different PDF/A standards and conformance levels. The PDF/A standards define the features and image compression technologies which help preserving the content of a file. At the same time the PDF/A standard supports different conformance levels. Through these levels, the accessibility requirements that impact the understanding of the content are being controlled. By knowing the different options for PDF/A, you can improve the value of your documents for your viewing, printing, sharing and archiving purposes.

PDF/A-1: This is the original PDF/A standard and comes with some restrictions regarding the use of fonts, color, annotations, and some other elements. It comes in level b (basic) and level a (accessible).
PDF/A-1b focuses mainly on the preservation of the visual appearance of a document while
PDF/A-1a adds features that improve the file's accessibility for physically impaired users. Its requirements include reliable text semantics and structure information to preserve the document’s natural reading order and logical structure.

PDF/A-2: This standard has several additions like a JPEG 2000 compression and optional content layers, as well as PDF packages. It also allows file attachments, as long as the attached documents themselves conform to PDF/A-1 or PDF/A-2. While PDF/A-2 also comes with level b and level a conformance, a new conformance - level u (unicode) - was introduced. It guarantees that the text can be reliably searched and copied.

PDF/A-3: Part three of the standard is almost identical to PDF/A-2. The only difference is that it allows arbitrary file formats to be embedded into PDF/A conforming files. These arbitrary file formats are CSV, CAD, XML, spreadsheet documents, word-processing documents and more.

Important to note: None of the different ISO standards replace their predecessor, and future developments to the PDF/A standard won't make current PDF/A versions obsolete. There is always a requirement for backward compatibility of PDF viewing applications, ensuring that older versions of PDF/A will still be displayed correctly.

PDF/A is a standard for archiving electronic documents in PDF format, specifically designed for long-term preservation of documents without loss of information.

PDF/A ensures that documents can be preserved and retrieved in their original format, regardless of changes in technology or software, making it suitable for long-term archiving of electronic documents.

PDF/A has specific requirements that are designed to ensure document preservation, such as embedding of fonts, prohibiting encryption, and requiring metadata standards. Regular PDFs may not meet these requirements and are not optimized for long-term preservation.

PDF/A documents can be created using specialized software or by converting existing PDF documents to PDF/A format using PDF conversion software. It's important to ensure that the resulting PDF/A document meets the requirements of the desired PDF/A version.