Interpress

Interpress is a special set of instructions used to tell printers exactly how a document should look. It was created at Xerox PARC and is based on the Forth programming language and an earlier graphics language named JaM. Even though Xerox couldn’t sell it widely, the people who made it, Chuck Geschke and John Warnock, started a new company called Adobe Systems in 1982 and created PostScript from it.

Some Xerox printers, like the DocuTech Network Production Publisher, still use Interpress today. It is also supported in software called Xerox Ventura Publisher. Interpress works with PARC’s InterScript, a program for creating rich text documents.

Interpress describes exactly how a finished document should appear, making all choices about lines, spacing, and image positions before the printing starts. This helps it work well on many different printers while keeping the original look of the document.

Functional Sets

Interpress has many features, so some printer makers might only use part of it. This helps them save time and money or make printers work faster. To keep things consistent, Interpress defines three standard groups of features.

The Commercial Set is for basic printing like text and simple images, useful in places that mainly handle text or scanned pictures.

The Publication Set includes everything in the Commercial Set, plus extra features like curved lines, filled shapes, and color options.

The Professional Graphics Set has all the basic imaging tools, full color, and special printing instructions.

Printing Instructions

This feature set lets you tell the printer what kind of paper to use, like its size, type, and color, how many copies to make, and which sides of the paper to print on. You can also add finishing actions such as stapling the pages together. These instructions are optional and depend on what the printer can do.

A more complex setup can include Nested Blocks and CONTENTINSTRUCTIONS, a special token that helps separate content instructions from the main document. Generally, content instructions are more important than the document instructions. Nested Blocks {BEGIN..END} help build big documents from smaller pieces.

Fonts

These are special rules about letters and shapes that are used at the beginning of documents because they help describe how the whole document should look.