The Adobe PDF Print Engine – APPE – is a printing and rendering platform from Adobe that specialises in the processing of PDF files and replaces the widely used Postscript Level 3 printing language and the CPSI (Configurable PostScript Interpreter). The Adobe PDF Print Engine produces the final print data for platesetters or proofing systems from PDF files.
The current version of the Adobe PDF Print Engine is version 6, which was released in 2022. This version brings numerous advanced features that improve colour accuracy and efficiency in modern print workflows. In addition, APPE version 6 now also supports new hardware platforms, such as the Apple M1 chip and AMD Ryzen, to ensure optimal performance on current systems, and there have also been permanent improvements in the past, such as version 3 of the Adobe PDF Print Engine, which has been enhanced by the Mercury RIP architecture. This allows PDF files to be processed even better in parallel. For example, four instances of APPE can process the same PDF file simultaneously on a modern computer, resulting in a much faster editing process. In large RIP environments, four computers, each with four processor cores, can also work on a PDF file simultaneously.
According to Adobe, APPE is the fastest RIP technology available. However, based on PDF/X-4 customer data, proof.de sometimes had very long calculation times (3.75 hours for one page with APPE 2.5 in two parallel instances), which was described as ‘normal’ when asked by Adobe due to the complexity of the file. Transparency flattening in particular can sometimes require very long APPE calculation times.
Difference between the Adobe PDF Print Engine and Postscript Level 3
In contrast to Postscript Level 3, the APPE does not understand Postscript. A Postscript file must therefore first be converted into a PDF file before it can be processed. The difference between the Adobe PDF Print Engine (APPE) and PostScript Level 3 lies mainly in their underlying technology and their respective areas of application. Both were developed by Adobe, but they serve different printing requirements and workflows.
Adobe PDF Print Engine (APPE):
- The PDF Print Engine is based entirely on the PDF format. PDF is a device-independent page description language format that is optimised for the digital workflow. The APPE processes PDF files natively without converting them to another format (such as PostScript). This allows more precise handling of modern graphics and printing requirements, such as transparencies, colour management and vector graphics. Modern graphic effects such as drop shadows, overlays and semi-transparent objects are printed correctly and efficiently. There is no need for flattening, where transparencies are converted into simple objects before printing.
- The PDF Print Engine uses advanced colour management that supports ICC profiles and modern colour standards such as Adobe RGB and sRGB directly in the PDF. This leads to more precise and consistent colour results, especially when interacting with different printing systems.
- The PDF Print Engine is the more modern approach and was developed specifically for the requirements of today’s digital and high-resolution printing. It is future-proof and integrates better into digital workflows that rely on PDF as the standard format.
Postscript Level 3:
- PostScript is a classic page description language and has been the standard in the printing industry for many years. PostScript Level 3 is the third and latest version of PostScript, which offers numerous improvements over previous versions, such as support for larger image formats, better compression and extended transparency functions. Nevertheless, PostScript is based on older technology concepts and processes data differently to PDF.
- PostScript was originally developed before transparencies were a common requirement. PostScript Level 3 can only process transparencies after a flat calculation. This process converts all transparent areas into simple, opaque (and often tiled) image data, which can lead to unexpected printing problems such as colour shifts or unclean edges.
- Although PostScript Level 3 offers colour management functions, they are less flexible and less comprehensive than those of the PDF Print Engine. As PostScript was primarily designed as a page description language and not as a colour management platform, the options are more limited.
- PostScript, although still widely used, is an older technology that is being replaced by PDF in many areas. PostScript-based workflows are still in use, but they are increasingly reaching their limits, especially with modern layouts and effects such as transparencies, shadows and more.