PDF/X, PDF/A, PDF/E: What is the difference, and why are there so many formats?

2023-11-01

PDF is an all-purpose file format that allows users to present and share documents regardless of software, hardware, or operating system. Over the years, several PDF subtypes have been created to meet the different needs of various industries. Let's look at some of the most popular formats: PDF/X, PDF/A, and PDF/E.

1. PDF/X

PDF/X is a professional standard for graphics interchange optimized for consistent and predictable printing. Unlike regular PDFs, which can include any content, like interactive elements and media files, PDF/X is limited to certain data types, making it especially suitable for sharing print-ready files.

Main characteristics of PDF/X:

Color model. All colors in a document must be defined in pre-known color spaces, typically CMYK or spot colors. It eliminates the uncertainties associated with color interpretation in printing.
Built-in resources. All necessary resources, such as fonts and images, must be embedded in the file. It ensures that the document will look the same on any hardware.
No interactive elements. There are no interactive elements such as comments, form fields, videos, and JavaScript.
The specified output format. The document must contain information about how it will appear when printed, which implies certain requirements for the placement and layout of pages.

PDF/X subtypes:

PDF/X-1a:

Based on the PDF 1.3 standard.
Colors are defined as CMYK or spot colors only.
Does not support ICC profiles.

PDF/X-3:

Supports CMYK, spot colors, and ICC profiles.
Allows you to use different color spaces in one document.

PDF/X-4:

Supports layers, transparency, and other new features available in PDF 1.6 and higher.
Supports multiple color spaces.

2. PDF/A

PDF/A is a subset of the PDF format designed to meet the needs for long-term storage of electronic documents. Unlike PDF standard, PDF/A prohibits components that can cause problems with a document's appearance over long periods of time, making it ideal for archiving.

Main characteristics of PDF/A:

Built-in resources. All resources for the correct display of the document (for example, fonts, and images) must be embedded in the file.
Lack of interactivity. Interactive elements such as JavaScript, audio, video, and executable files are prohibited.
Color stability. The document must use a stable color model to ensure long-term display consistency.
Prohibition of external dependencies. You may not refer to external resources that may change or disappear over time.

PDF/A subtypes:

PDF/A-1:

Based on the PDF 1.4 standard.
It is divided into two parts: PDF/A-1a for full compliance, including structure tags for accessibility, and PDF/A-1b for basic visual compliance.

PDF/A-2:

Based on the PDF 1.7 standard.
Includes improved support for embedded annotations, layers, transparency, and compression.
It is also divided into compliance levels: PDF/A-2a, PDF/A-2b, PDF/A-2u.

PDF/A-3:

Extends PDF/A-2 allowing to build in embedded files of any format (including, for example, XML, CSV, or CAD files).
It is also divided into compliance levels: PDF/A-3a, PDF/A-3b, PDF/A-3u.

3. PDF/E

PDF/E is a subset of the PDF format designed specifically for engineering, architecture, and construction professionals. This standard addresses the need for sharing, viewing, and printing dynamic technical documents, including diagrams, drawings, and 3D graphics.

Main characteristics of PDF/E:

Support for complex graphics. Including layers, transparency, 3D models, and interactive elements.
Metadata. Enhanced metadata for improved search and management of document content.
Precise geometry. For accurate reproduction of geometric objects such as lines, curves, and surfaces.
Embedded files. Ability to include related or source files such as specifications or CAD data.

Why so many formats?

Various industries have different needs. The creation of specialized PDF subsets allows us to meet these needs without creating an entirely new standard. These profiles ensure standardization, predictability, and reliability for specific applications.

Are these formats available in FastReport .NET?

FastReport .NET has most export formats, only PDF/E is missing. These formats can be used both in the designer and the application code. To select the desired format in the designer, click "Save" and "PDF format." Then go to the "Settings" tab and select the needed format.

At the end, we will receive the required file in the desired format.

To export to a specific format, we need to create an application, connect the FastReport package, and write the required code. Below is an example of how to save a PDF as PDF/A.

 Report report = new Report();
 report.Load("PathToYourReport.frx");
 // Setting up PDF export
 PDFExport pdfExport = new PDFExport();
 // For export to PDF/A format
 pdfExport.PdfCompliance=PDFExport.PdfStandard.PdfA_2a; 
 // You can select the desired compliance level
 report.Prepare();
 report.Export(pdfExport, "OutputPath.pdf");

Conclusion

Although there are many PDF subtypes, each was developed with a specific purpose and to meet the needs of a specific industry. The choice is entirely yours, which format and for what purposes you need it.

November 20, 2024