Warnock worked with Geschke at Xerox's Palo Alto Research Center. Unable to convince Xerox management of the approach to commercialize the InterPress graphics language for controlling printing, he, together with Geschke and Putman, left Xerox to start Adobe in 1982. There, they developed an equivalent technology, PostScript, from scratch and brought it to market for Apple's LaserWriter in 1985.

In the spring of 1991, Warnock outlined a system called "Camelot", that evolved into the Portable Document Format (PDF) file-format.
— Rlanman,et al (2023) "John Warnock" en.wikipedia.org [1]
While at Xerox PARC, Warnock worked on improving the typographic quality of computer grayscale displays. In 1982, Drs. John E. Warnock and Charles M. Geschke formed Adobe Systems to develop software that integraters text and graphics, and is also output device independent. Their effort resulted in PostScript, Adobe System's first product.

PostScript started in the Evans and Sutherland days when we were doing a harbor simulator for the Maritime Academy. We had to build a digital model of New York harbor, with 1,500 buildings and tank farms, and all the bridges and buoys and everything, all the landscape. The simulator was going to project the view of the harbor as seen from the bridge of the ship. We needed to write a huge, three-dimensional database and a lot of real-time software to make the simulator work.

We decided the most stupid thing we could do was to design this database in a form that would be used directly by the simulator. So we started building this huge database in text form. In digitizing the database and in building this big 3D model, it became very obvious that rather than having a static data structure in the text file, it was much more reasonable to have a language. So that's where the basic ideas of PostScript got started, in developing a language for this 3-D graphic database.
—Susan Lammers (1986) Programmers at Work

We have software called Postscript. It does image generation for the text, line graphics, as well as photographs on the printer pages. The way that we would work with printer manufacturers is that we would help them design the controller boards for those printers. They would manufacture the whole thing, and we would put the software in it, so the software was built in as part of the printers. We were paid a royalty by the printer manufacturers for our software and technology.
— Roger Chen, Zhan Li (2006) "An interview with Chuck Geschke and John Warnock, founders and chairmen of Adobe systems" Journal of Asia Business Studies (Vol. 1, Issue 1) [2]

This project's goal is to solve a fundamental problem that confronts today's companies. The problem is concerned with our ability to communicate visual material between different computer applications and systems.

Most programs print to a wide range of printers, but there is no universal way to communicate and view this information electronically. What industries badly need is a universal way to communicate documents across a wide variety of machine configurations, operating system and communication networks. These documents should be viewable on any display and should be printable on any modern printers. If this problem can be solved, then the fundamental way people work will change.

The invention of the PostScript language has gone a long way to solving this problem. PostScript is a device independent page description language. Adobe's PostScript interpreter has been implemented on over 100 commercially available printer products. Over 4000 applications output their printed material to PostScript machines. This support for PostScript as a standard make the PostScript solution a candidate for this electronic document interchange.

There are at least two technical approaches to the Camelot project. Both solutions depend on the PostScript technology. One approach is to try to make Display PostScript and PostScript implementations smaller and faster so that they can run on the vast majority of today's machines. This approach has been tried and is extremely difficult. A second approach is to divide the problem into smaller problems. An approach to the Camelot project will now be described that will divide the problem into smaller pieces.

One obvious application for this is in its use in electronic mail systems. Imagine being able to send full text graphics and documents (newspapers, magazine articles, technical manuals, etc) over electronic mail distribution networks. These documents could be viewed on any machine and any selected document could be printed locally. This capability would truly change the way information is managed.
— John Warnock "The Camelot Project"