The history of PostScript

1991: PostScript level 2

Around 1991, Adobe released the next revision of PostScript called level 2. It was a pretty significant upgrade that had been awaited eagerly by the prepress community.

The most important features are:

• Improved speed and reliability: Limitcheck and VMerror PostScript errors got really ugly right before level 2 popped up. Adobe fixed all of this by improving the memory management of its code and by optimizing the code. This also gave us better performance, especially with rotated scans.
• Support for in-rip separation: Level 2 RIPs are capable of receiving a composite PostScript file and performing the colour separation themselves. This is not a mandatory feature and there are certainly functional differences between level 2 RIPs from different manufacturers.
• Image decompression on the RIP: Level 2 RIPs can decompress JPEG and CCITT group 4 compressed images.
• Support for composite fonts: This is important for Asian countries which use bigger character sets than we do in Europe. Apple was supposed to support composite fonts through QuickDraw GX. This can nowadays be found in an Apple closet somewhere, next to other breakthroughs like OpenDoc and the Newton.
• Font and pattern caching: With level 2, boring things like font cache deletes disappeared. Pattern caching got picked up years later by some imposition applications like PressWise and Preps.
• Improved drivers: essentially LaserWriter 8 on Macintosh and the Adobe PostScript driver 2.X for Windows 3.1, together with the appropriate PPD-drivers.
• Improved screening algorithms: For a lot of RIP manufacturers, this was old news by the time level 2 arrived. Agfa for instance, had already been shipping its Balanced Screening technology a year earlier, offering high quality moiré free screens for offset use. The Adobe version is called Accurate Screening.

The slow adoption of level 2

Adobe made a big mistake by first publishing the level 2 specs and then starting work on the actual implementation. Much to their embarrassment, competitors came up with level 2 emulators faster than Adobe thought possible.
Although PostScript level 2 offered immediate advantages, it took ages before applications actually started using the new functionality. A feature like in-rip separation still wasn’t supported properly by XPress 5, 11 years after the release of level 2.

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