Prepress is the term to describe all of the processes that occur before printing and finishing. Since many publications nowadays are published both in print and electronically, many refer to the shared processes as premedia services instead.
The prepress processes that are listed below may take place at one single location, such as a large publishing and printing company, or at a variety of places. Usually some tasks happen at a publisher while others take place at a printer or a dedicated prepress company (which are sometimes referred to as service bureaus or trade shops).
- Design: Since the advent of desktop publishing, many people in the printing industry no longer consider design to be a prepress task. The design process includes:
- Preparing data, which includes copyediting and product photography, such as for a mail order catalog.
- Creating the layout is done using one of the leading design application such as Adobe InDesign or QuarkXPress. People outside the graphic arts community may use tools like Microsoft Office or Publisher. There is also a wide range of specialized applications for tasks like database publishing.
- The correction cycle includes processes such as proof reading and image retouching, for which Adobe Photoshop is the leading application.
- Preflighting: Before finished pages go through the remaining processes, a validation is done to check if all the data meet the necessary production requirements.
- Proofing: During the design phase there are already page proofs being created. Proofs are usually also made by the company that is responsible for the printing. This can be done for internal checks of the impositioning (imposition proofs) as well as for their customer who needs to sign off the proofs for approval. More and more such proofs are softproofs that are evaluated on a monitor. Hardcopy proofing remains popular when there is sufficient time for it and for color critical or expensive jobs.
- Imposition: Depending on the final output device a number of pages will be combined into signatures.
- Output to the final output device such as a digital press, filmsetter or CtP device. To output data, pages or complete flats have to be ripped or rendered. This process usually also includes:
- transparency flattening: transparency effects such as drop shadows behind text need to be resolved.
- color separation
- color management
Some people prefer to delay the above destination specific conversions to the very last moment. This is commonly referred to as late binding. Once a job is printed, its data usually go into an archive.
Many of the above steps are nowadays heavily automated, by either stand-alone applications or prepress workflow systems. The automation also allows for more elaborate communication processes:
- Exchanging data such as the final layout may still happen using a physical carrier such as a DVD. In the past people usually submitted the native data, meaning the original layout file(s) and all associated images, fonts and other data. Nowadays PDF files are often used instead.
- Increasingly the internet is used for submitting jobs. This is referred to as web-to-print.
- When the data exchange focuses purely on page content, solutions range from using an FTP server or e-mail system to using file sharing tools such as DropBox or YouSendIt. A more sophisticated web portal can add functions such as preflighting and page approval.
- A digital storefront enables a printer to not just capture page content but also order related information. Such a system can also facilitate reorders and allow print buyers to customize documents on-line.
- Job related data such as the job ID or run length are exchanged between systems such as an MIS (Management Information System), a prepress workflow, press control system and finishing equipment. Protocols such as JDF allow systems from different vendors to exchange the necessary data.
- Many projects nowadays are published using other media besides print as well. The content of a magazine may also be published on the web while the content of a book is repurposed for e-books . There are special tools and protocols such as XML to facilitate cross media publishing.
Working in prepress
Over the past 20 years employment in prepress has declined rapidly due to the increased use of computers and software automation. This trend is unlikely to stop – in the US job market employment in prepress is expected to drop 16 percent from 2006 to 2016, going from 119,000 workers down to 100,000.
The history of prepress
This site contains an extensive description of the history of prepress. You can read either the summary or a more detailed year-by-year story, which starts in 1950. There are also separate pages on the history of printing, fonts, PostScript and PDF.
Other sources of information
Prepress has evolved a lot during the past 20 years. Many processes got automated, jobs disappeared and the terminology changed. The description of prepress on sites like Wikipedia doesn’t seem to have been adapted to this rapid evolution. Be aware that much of the stuff that is available on the web about prepress is simply outdated. If you know of any interesting sites, please add a comment to this page.