1998: PostScript 3

For some obscure reason, Adobe preferred to call the latest update PostScript 3 instead of PostScript level 3. Compared to level 2, PostScript 3 seems like an insignificant upgrade. In some ways this can be understood since a lot of applications are still struggling to support level 2 properly.

The main advantages of PostScript 3 are:

• Support for more than 256 graylevels per colour. Adobe has included 12-bit screening in their PostScript code. This allows for up to 4096 graylevels per colour. In the past, the limitation of 256 graylevels was sometimes visible as banding, especially in blends.
• Support for PDF. PostScript 3 RIPs support both PostScript level 2 and PDF-files.
• Improved support for in-rip separation: PostScript level 2 RIPs are already capable of performing a colour separation in the RIP itself, but some types of images like duotones or hexachrome images could not be handled in such a workflow. PostScript 3 contains an extra colour space called DeviceN. If a non-CMYK colour image is encoded in this colour space, a PostScript 3 RIP is capable of performing a correct colour separation of that image.
• Web-ready printing. In these days of internet hype, Adobe couldn’t stay behind and added some internet functionality to PostScript. Funnily enough none of Adobe’s OEM-customers seem to have bothered implementing it.

2006: The beginning of the end?

In 2006 Adobe announced the Adobe PDF Print Engine (APPE). This is a complete rewrite of their RIP architecture. Instead of relying on PostScript as its core page description language, APPE uses PDF. Designers can now export PDF files from a layout application such as InDesign. These pages are sent to a printer who uses a PDF based workflow system to check, trap and impose thoses pages. The PDF Print Engine is then used to create plate-ready data. In the entire chain, PostScript is no longer used.

Although some vendors have started shipping products based on APPE, it will still take years before the entire industry has made the switch to a fully PDF based data flow.

When asked if Adobe would ever introduce PostScript 4, an update that would include all of the new features made available in PDF, Dov Isaacs from Adobe had the following to say in a thread on the Printplanet forums:
“Absolutely isn’t going to happen. PostScript is a programming language, not really a page description language. By its very nature, it does not provide for really reliable end-to-end workflows since by definition, content can change on the fly. Fun for hackers, disaster for people who need to earn a living.
No, there is not a PostScript Language Level 4 sitting on disk somewhere waiting for marketing to give a signal. Beginning with PDF 1.4, all additions to the Adobe imaging model went into PDF and not PostScript.
To be very clear, Adobe will continue to license PostScript technology through our OEM partners as long as there is a demand for it from their customers. We will also continue support a gateway from PostScript to PDF via our Distiller technology in Acrobat. Adobe will continue to support EPS as a legacy graphics format for import of non-color managed, opaque graphical data into Adobe applications (such as InDesign and Illustrator). Although we certain do not recommend that new graphical content be stored in EPS format (except to satisfy the need to import data into page layout programs that aren’t quite PDF-centric — no need to mention names here!), our user base should feel comfortable that there is no need to worry about a need to convert their very sizable libraries of EPS-based graphic assets.”

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