Job Definition Format
Encyclopedia
Job Definition Format is a technical standard being developed by the graphic arts
Graphic arts
A type of fine art, graphic art covers a broad range of art forms. Graphic art is typically two-dimensional and includes calligraphy, photography, drawing, painting, printmaking, lithography, typography, serigraphy , and bindery. Graphic art also consists of drawn plans and layouts for interior...

 industry to facilitate cross-vendor workflow
Workflow
A workflow consists of a sequence of connected steps. It is a depiction of a sequence of operations, declared as work of a person, a group of persons, an organization of staff, or one or more simple or complex mechanisms. Workflow may be seen as any abstraction of real work...

 implementations of the application domain
Application domain
In Microsoft's Common Language Runtime , an application domain is a mechanism used to isolate executed software applications from one another so that they do not affect each other...

. It is an XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....

 format about job ticket
Job ticket
Job tickets are monthly or annual season tickets, purchased en block from a regional transport association by public or private organisations for use by their staff....

, message description, and message interchange. JDF is presently managed by CIP4, the International Cooperation for the Integration of Processes in Prepress, Press and Postpress Organization. JDF was initiated by Adobe Systems
Adobe Systems
Adobe Systems Incorporated is an American computer software company founded in 1982 and headquartered in San Jose, California, United States...

, Agfa, Heidelberg
Heidelberger Druckmaschinen
Heidelberger Druckmaschinen AG is a German precision mechanical engineering company with head offices in Heidelberg . It is a manufacturer of offset printing presses sold globally. The company has a worldwide market share of more than 47% in this area and is the largest global manufacturer of...

 and MAN Roland
MAN Roland
manroland AG manufactures newspaper web offset presses, commercial web offset presses, and sheetfed offset presses for commercial, publications and packaging printing.The company has production facilities in Offenbach am Main and Augsburg...

 in 1999 but handed over to CIP3 at Drupa
Drupa
Drupa is the largest printing equipment exhibition in the world, held every four years at Messe Düsseldorf GmbH, City of Düsseldorf, Germany....

 2000. CIP3 then renamed itself to CIP4.

The initial focus was on sheetfed offset and digital print workflow, but has been expanded to web(roll)-fed systems, newspaper workflows and packaging and label workflows.

It is promulgated by the prepress industry association CIP4, and is generally regarded as the successor to CIP3's Print Production Format (PPF) and Adobe Systems
Adobe Systems
Adobe Systems Incorporated is an American computer software company founded in 1982 and headquartered in San Jose, California, United States...

’ Portable Job Ticket Format (PJTF).

The JDF standard is currently at revision 1.4a. The process of defining and promulgating JDF began circa 1999. The standard is in a fairly mature state; and a number of vendors have implemented or are in the process of implementing it. JDF PARC, a multivendor JDF interoperability demonstration, was a major event at the 2004 Drupa
Drupa
Drupa is the largest printing equipment exhibition in the world, held every four years at Messe Düsseldorf GmbH, City of Düsseldorf, Germany....

 print industry show, and featured 21 vendors demonstrating, or attempting to demonstrate interoperability between a total of about forty pairs of products.

JDF is an extensible format. It defines both JDF files and JMF, a job messaging format
Job messaging format
The Job Messaging Format is the language used to communicate between JDF agents and controllers. JMF is part of the JDF specification. JMF also is built in XML and is part of the JDF schema...

 based on XML over HTTP. In practice, JDF-enabled products can communicate with each other either by exchanging JDF files, typically via "hot folders," or the net or by exchanging JMF messages over the net.

Acrobat 7 includes a menu item to create a JDF file linked to a PDF
Portable Document Format
Portable Document Format is an open standard for document exchange. This file format, created by Adobe Systems in 1993, is used for representing documents in a manner independent of application software, hardware, and operating systems....

 file. This starts with the 'intent' for the job. More JDF detail is added later in various steps of the production workflow.

As is typical of workflow
Workflow
A workflow consists of a sequence of connected steps. It is a depiction of a sequence of operations, declared as work of a person, a group of persons, an organization of staff, or one or more simple or complex mechanisms. Workflow may be seen as any abstraction of real work...

 systems, the JDF message contains information that enables each "node" to determine what files it needs as input and where they are found, and what processes it should perform. It then modifies the JDF job ticket to describe what it has done, and examines the JDF ticket to determine where the message and accompanying files should be sent next.

The goal of CIP4 and the JDF format is to encompass the whole life cycle of a print and cross-media job, including device automation, management data collection and job-floor mechanical production process, including even such things as bindery, assembly of finished products on pallets.

Before JDF can be completely realized, more vendors need to accept the standard. Therefore few users have been able to completely utilize the benefits of the JDF system. In finishing and binding, and printing there is a tradition of automation and few large enough dominating companies that can steer the development of JDF system. But it is still necessary for the manufacturers of business systems to fully support JDF. The same progress has not been made here probably because many of these companies are small specialty companies who haven't the resource to manage such development and who don't specialize on graphic production.

Introduction to Proofing

Before describing the implementation of proofing in JDF, it’s better to know a little about the terminology
that will be used.
  1. Proofing: the process of producing a printed output on a device (proofer) that emulates the best it can the supposed printed output on press (the final production device that can be a conventional press, a digital press…) where the final printed product will be produced. Prepress proofing (or off-press proofing) provide a visual copy without creating a press proof (the process is cheaper).
  2. Soft proofing: the same as proofing, but the proofer is actually a screen.
  3. Approval: the process of approving or rejecting the proofing (or the soft proofing). Comments and annotations may be added to describe the reasons of the decision and to give instructions on what changes to do.


The original input files have to be processed to be printed on the final press (interpreting, rendering, screening, color management....) and the same to be printed on the proofer (different characteristics). The decision on which of the processing steps will be executed once (common both for printing on the proofer and on the press) and which not will depend on many parameters (characteristics of the proofer device, user requirements, workflow requirements…). The proofing has to take in account the consistency between the press and the proofer.

Proofing in JDF

In JDF 1.1, proofing and soft proofing were defined as an atomic process on which the input were all the parameters required for a successful process. This has some drawbacks:
  1. Lack of flexibility: the semantics is specific for one workflow therefore limited to the definition of the processes and the resources that it can take as input.
  2. Lack of control: it is difficult to define the input resources with all the information required for control.
  3. Duplication: similar information has to be used to define both proofing and printing. If different resources are used, this will result in duplication.


From JDF 1.2 proofing and soft proofing were deprecated in behalf of a combined process to specify the proofing workflow. The job ticket explicitly defines the processing and provides the flexibility to implement them in different workflows. In order to do that, the atomic processes were made capable of keeping all the information necessary to specify different configurations/options.

Combined Processes for Proofing

It is impossible to describe proofing by a unique combination of processes which in turn will depend on the capabilities of the RIPs (Raster image processor
Raster image processor
A raster image processor is a component used in a printing system which produces a raster image also known as a bitmap. The bitmap is then sent to a printing device for output. The input may be a page description in a high-level page description language such as PostScript, Portable Document...

), the devices used for proofing and the proofing production workflow. It is still possible to define a generic combined process for the proofing. This will allow it to describe its step in a workflow. The generic combined proofing process combines the following JDF processes:
  • ColorSpaceConversion (1): converts the contents of the input RunList from the input color spaces to the color model of the press.
  • Interpreting: interprets the input RunList file(s) and converts them to an internal display list in order to go through the Rendering.
  • Rendering: renders the raster data.
  • ColorSpaceConversion (2): converts the data from the press color model to the proofer device color model.
  • Screening: screens the raster data.
  • Imposition: if imposition proofing is done, combines the pages and marks on the imposed sheets.
  • ImageSetting: specifies the actual printing of the proof. Depending on the characteristics of the proofing device DigitalPrinting can be used as well.


The ordering is not completely strict (same result may be achieved with different order combination of steps), but there are some precedence rules: the first color space conversion must be done before the second one, rendering must be done after interpreting, screening in turn must be done after rendering and the second color conversion, ImageSetting/DigitalPrinting must be done after screening.

Combined Processes for Soft Proofing

Compared to proofing, since no printed proof is produced, no ImageSetting/DigitalProofing processes are required. Moreover the rendered data is sent directly to the Approval process that must implement a user interface to show those data on the display and allow him/her to approve/reject the proof and eventually annotate it using digital signature. All the ordering consideration are still valid.

ColorSpaceConversion

In a production workflow with proofing, there must be both the conversion of the input asset color spaces to the press color space and the one of press color space to the proofer color space. So in JDF two different ColorSpaceConversion processes are required and depending on the exact workflow and on the capabilities of the devices, they can be included in the same combined process.

Interpreting and Rendering

Input data to the proofing combined process usually required both interpreting (with the exception of JDF ByteMap) and rendering. In these cases they will be included in the combined process describing the proofing step.

Screening

Two possibilities:
  • Proofer can emulate the screening of the press: Screening should be performed once at the ripping combined process and the halftoned data should be sent directly to the proofing combined process.
  • Proofer is a "contone proofer": one Screening process for the press and one for the proofer.

ImageSetting/Digital Printing

For printing the proof ImageSetting/DigitalPrinting process has to be specified at the end of the proofing combined process in order to define how the proof is actually printed.

HP Example: Cutting of Proofing Time

HP currently incorporates JDF into its proofing products. Even if it’s only one step in the total process JDF cuts time from the printing process making printers more efficient because proofing traditional generation and delivery of proofs can take days.

HP sends PDF files to a remote proofing. JDF file enables the inclusion of job information (color profiles, job ticket details…) that is sent to the client. In the future marking up the proof and digital signatures for approval will be implemented.

See also

  • PPML
    PPML
    PPML is an XML-based industry standard printer language for variable data printing defined by PODi. The industry-wide consortium of 13 companies was initially formed to create PPML, and now has more than 400 member companies.-Overview:PPML is an open, inter-operable, device-independent standard...

     (Personalized Print Markup Language)
  • Print Production Format
  • Portable Job Ticket Format
  • Printing Industry Markup Language
  • Internet Printing Protocol
    Internet Printing Protocol
    In computing, the Internet Printing Protocol provides a standard network protocol for remote printing as well as for managing print jobs, media size, resolution, and so forth....

  • CUPS
  • Workflow management

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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