PDF/X, like PDF/A, is a subset of PDF. The purpose of PDF/X is to provide designers, drafters, engineers, and graphic artists with an electronic file format that can be printed correctly by any service provider. This format is ideal for the transfer of print-ready files by most network companies; here, the sender and receiver of print-ready information are not strongly correlated. In addition to providing a solid delivery format for print jobs, PDF/X has other benefits, including a file viewer, better compression (smaller file size), and support for spot color printing colors that recognize printing conditions ( such as which file is ready), and more. However, like PDF/A, the benefits of PDF/X come with some compromises. Features such as transparency, encryption, and JBIG2 compression are prohibited in PDF/X.
The PDF/X standards are divided into three categories:
PDF/X-1a: This standard is ideal for file senders who want to maintain the most control over their printing jobs. It supports blind send exchange of information and conforms to the general requirements used in many parts of the world. This type of document itself contains all the elements that need to be printed. Color data can only be in CMYK mode and spot colors, all images, and fonts must be built into the file, and transparent layers are prohibited. Is a subset of the PDF/X-3 standard.
PDF/X-3: This allows the use of device-independent color forms, as well as device-dependent data that is not flagged. The most important difference between PDF/X-3 and PDF/X-1a is the fact that PDF/X-3 files contain color-managed data. This means that any tool that can read PDF/X-3 files can also read PDF/X-1a files. PDF/X-3 is a subset of PDF/X-2.
PDF/X-2: Unlike the previous two formats designed to support blind-feed exchanges, PDF/X-2 is protected for exchanging information; it is more of a dialogue between the sender and the receiver of the information. PDF/X-2 is very similar to PDF/X-3, but PDF/X-2 allows the use of externally referenced data.
3. PDF/E (suitable for multimedia file processing)
PDF/E is mainly aimed at the engineering technology industry and is used for interactive engineering file exchange, especially for some of the latest features used by the engineering technology community of PDF technology, including object-level metadata and 3D models.