The history of Adobe's PDF

The history of Adobe's PDF acrobat format file documents IPS
The history of PDF
     The paperless office. Remember that buzz word that never seems to vanish completely even though history has proven that the use of computers has lead to an increase in the use of paper?
     PDF started off on the dream of a paperless office, as the pet project of one of Adobe's founders, John Warnock. Initially it was an internal project at Adobe to create a file format so documents could be spread throughout the company and displayed on any computer using any operating system.
     Adobe already had two more-or-less fitting technologies: PostScript as a device and platform independent technology to describe documents and Adobe Illustrator as an example of an application that ran on several platforms (OK, actually on 2: Windows and Mac but that is 99 percent of all computers) and could open and visualize fairly simple PostScript files, even if they were created using other applications. The engineers at Adobe enhanced these two technologies and created both a new file format (PDF, which is really a kind of optimized PostScript) and a set of applications to create and visualize these files.

PDF 1.0
     The first time Adobe actually talked about this technology was at a Seybold conference in San Jose in 1991. At that time, it was referred to as "IPS" which stood for "Interchange PostScript". Version 1.0 of PDF was announced at Comdex Fall in 1992 where the technology won a 'best of Comdex' award. The tools to create and view PDF-files, Acrobat, were released in mid 1993. This first version was of no use for the prepress community. It already featured internal links and bookmarks and fonts could be embedded but the only colour space supported was RGB.
     The original code name for what later became the Acrobat software was 'Carousel'. That is why the file type of a PDF file on Macintosh was 'CARO'.
     Adobe asked a steep price for the tools to create PDF files and you even had to pay 50 dollar for Acrobat Reader. This approach didn't exactly turn PDF into a popular format overnight. Later on, Adobe dropped the price of Acrobat and launched the free version of Acrobat Reader.

PDF 1.1

Acrobat 2 became available in September 1994. It supported the new PDF 1.1 file format which added support for:
  • external links
  • article threads
  • security features
  • device independent colour notes
     Acrobat 2.0 itself also got some nice enhancements, including a new architecture of Acrobat Exchange to support plug-ins in and the possibility to search PDF files.
     Adobe themselves were one of the first big users of PDF. They distributed all documents for developers as PDF files. Another early adoptor of PDF were the US tax authorities who distributed forms as PDF files.
     Acrobat 2.1 added multimedia support with the possibility of adding audio or video data to a PDF document.
     In those days, PDF was not the only attempt at creating a portable device and operating system independent file format. Its biggest competitor was a product called Common Ground.
     In 1995, Adobe began shipping Acrobat Capture for a rather steep 4000 US dollar. At the same time, Adobe also started adding PDF support to many of its own applications, including FrameMaker 5.0 and PageMaker 6.

PDF 1.2: the prepress world wakes up      In 1996, Adobe launched Acrobat 3.0 (code name: Amber) and the matching PDF 1.2 specifications. PDF 1.2 was the first version of PDF that was really usable in a prepress environment. Besides forms, the following prepress related options were included:
  • support for OPI 1.3 specifications
  • support for the CMYK colour space
  • spot colours could be maintained in a PDF
  • halftone functions could be included as well as overprint instructions.
     The release of a plug-in to view PDF files in the Netscape browser increased the popularity of PDF file on the booming internet. Adobe also added the possibility to link PDF files to HTML pages and vice versa. PDF also slowly began to get accepted by the graphic arts industry. Initially the black-and-white digital printing market began using PDF for output on fast Xerox digital presses.
     In Acrobat 3, the open architecture of Acrobat Exchange finally began to pay of and a lot of interesting prepress xtensions appeared in '97 and '98, including several essential prepress tools. Among them were PitStop and CheckUp from Enfocus software and CrackerJack from Lantanarips. Agfa was the first major company that promoted the use of PDF for full colour commercial printing with their Apogee system, launched in 1998. Other manufacturers followed soon after.
     Although vendors pushed hard to get PDF of the ground, the market was a bit slow to react. This was mainly due to the fact that the use of PDF required additional tools as well as some know-how on the file format, its limitations and curiosities. People also got disappointed of PDF when they discovered that it is a very open standard. Although the PDF standard was usable in a prepress environment, there were simply to many ways in which a perfectly valid but non-usable PDF-file could be created.

PDF/X-1: a (very) slowly emerging standard
     To solve the above issue, a consortium of prepress companies got together and released the PDF/X-1 standard in 1998. PDF/X-1 is based on the PDF 1.2 file specifications but it is a very well defined description on what a PDF file should look like to allow for blind transfers. A PDF/X-1 file is a file in which you are sure that all fonts are included, all highres images are embedded and so on.
     Although PDF/X-1 is based on PDF 1.2, a number of extra operators were added. They are described in Adobe technote 5188 and include:
  • the possibility to embed extra data like copydot files
  • support for ICC based colours
  • the definition of a bleed, trim and art-box
  • a key that documents whether the file has already been trapped.
You can find more information on PDF/X on this page.

PDF 1.3: listening to prepress needs
     Acrobat 4, launched in April 1999, brought us PDF 1.3. The new PDF specs included support for:
  • 2-byte CID fonts
  • OPI 2.0 specifications
  • a new colour space called DeviceN to improve support for spot colours
  • smooth shading, atechnology that allows for efficient and very smooth blends (transitions from one colour or tint to another).
  • annotations

Acrobat itself also included its fair share of novelties including:
  • support for page sizes up to 5080 x 5080 mm, up from 1143 x 1143 mm
  • Webcapture
  • a series of pre-set configurations in Acrobat Distiller, making it easier to create valid PDF-files.
  • a very confusion change of names: the former Acrobat Exchange was renamed to Acrobat, which also happens to be the name of the entire software suite.
  • easy integration in Microsoft Office.
     The initial version of Acrobat 4, aptly numbered 4.0, contained quite a lot of bugs that limited the usefulness of the software for prepress purposes. Users got quite upset when Adobe tried to charge for the bugfix, Acrobat 4.05. Luckily Adobe listened to its users and send a free copy to registered users (We did have to wait 4 months or so for it in Europe).
     Although there were still some issues that need fixing in the prepress support of PDF, it can hardly be disputed that PDF has become a standard on the market. There were more than 100 million copies of Acrobat Reader downloaded from the web.

Illustrator 9 and PDF 1.4: Acrobat will have to wait
     Mid 2000, Adobe did something weird: they released Illustrator 9. Although launching a new version of a drawing application is not that bizarre, Illustrator 9 did have one amazing feature: it was the first application to support PDF 1.4 and its transparency feature. This was the first time Adobe did not accompany a new version of PDF with a new version of Acrobat. They also did not release the full specs of PDF 1.4, although technote 5407 documented the transparency support in PDF 1.4.
Acrobat 5
     In May 2001 Acrobat 5 did finally show up and PDF 1.4 became a reality. The file format itself has not changed that much. For prepress, the things that are worth mentioning are:
  • the addition of transparency support, which allows an object like text or an image to see through.
  • improved security, including 128-bit encryption and the option of setting the quality of printing (you can define that a PDF can be printed but only in low resolution)
For non-prepress users, Adobe also added some goodies to the PDF 1.4 file format:
  • There is improved support for JavaScript, including JavaScript 1.5 and better integration with databases.
  • "Tagged PDFs" are PDF files that also contain structural information about the data that are representated by the PDF document. This means that meta-information like defining titles, blocks of text,... can now be part of a PDF-document.
    • This makes it easier to create PDF-files that can adapt themselves to the device they will be used upon. This new feature is mainly meant for the emerging market of ebooks, since it allows PDF files to be repurposd so they can be used on a wider variety of systems. Adobe has started shipping a version of Acrobat Reader that runs on PalmOS PDA's.
    • It will also make it easier to repurpose content
     Most users will be far more pleased with all of the new features that Acrobat itself offers. Prepress users enjoy the following enhancements:
  • Acrobat itself can now correctly display overprints. So if a user puts a yellow box in overprint on a cyan background, Acrobat 5 can now display the resulting green box. Please note that this option is switched off by default.
  • Acrobat 5 can also perform batch operations which can be used, among others, to export folders full of PDF files to EPS-es.
  • Distiller can now compress images that use DeviceN colours. This means that PDF files containing multitones will now be a lot smaller.
  • Acrobat and Distiller also use an improved colour management engine, known as 'ACE', which provides finer control.
  • Annotating PDF-files is now more flexible and can also happen across the internet.
Acrobat 5 is a more significant upgrade for non-prepress users:
  • The forms-functionality was enhanced a lot.
  • The user interface of Acrobat now resembles Microsoft Office applications a lot more. The integration of Acrobat within Office has also improved.
  • You can now start Distiller or Catalog from within Acrobat.
  • Thumbnails are created automatically when a PDF file is opened in Acrobat.
  • There are more and improved export-filters in Acrobat, including an option to export data from a PDF to the RTF file format. This makes it easier to maintain the appearance of files when exporting them to word processors.
  • Interestingly enough, Acrobat 5 is also a downgrade for some users: Adobe has replaced the 'Paper capture' plug-in that can OCR scanned pages to create a true text-based PDF by a fairly limited Web service.

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The history of Adobe's PDF acrobat format file documents IPS