ghent pdf output overview and practice · ghent pdf output suite 4.0: overview and practice 2.2 why...

White Paper

Ghent PDF Output Suite 4.0: Overview and Practice Author Jason Lisi

Education Member, Ghent Workgroup [email protected] Date 27 March 2013 Status Final

[email protected] www.gwg.org

Ghent PDF Output Suite 4.0: Overview and Practice

Table of Contents 1 Introduction ................................................................................................... 3 1.1 About the Ghent Workgroup .......................................................................... 3 1.2 About the Ghent PDF Output Suite 4.0 ............................................................ 4 1.3 About This Document .................................................................................... 4 1.4 More Information ......................................................................................... 4 2 The Ghent PDF Output Suite 4.0 ....................................................................... 5 2.1 What is the Ghent PDF Output Suite 4.0? ........................................................ 5 2.2 Why a New Output Suite? .............................................................................. 6 2.3 Comparison with the Ghent Output Suite 3.0 ................................................... 6 3 Using the Ghent PDF Output Suite 4.0 ............................................................... 7 3.1 How Can You Use the Ghent PDF Output Suite 4.0? .......................................... 7 3.2 Which Patches Test What? ............................................................................. 8 4 Conclusion and Further Information .................................................................. 9 4.1 Conclusion .................................................................................................. 9 4.2 Further Information ...................................................................................... 9 5 Case Study: Using the Ghent PDF Output Suite 4.0 to conform to a National Standard for Digital Magazine Ad Submission .................................................................. 10 5.1 About Magazines Canada .............................................................................. 10 5.2 The Challenge ............................................................................................. 10 5.3 The Process ................................................................................................ 11 5.4 The Outcome .............................................................................................. 12 6 12


1 Introduction The purpose of this white paper is to provide an overview of the Ghent PDF Output Suite 4.0, and offer examples of ways that this suite can assist companies with developing and maintaining workflows that process and utilize PDF/X files in correct and consistent manner.

1.1 About the Ghent Workgroup The Ghent Workgroup (GWG) is a worldwide assembly of graphic arts stakeholders (user associations, vendors, consultants, educational institutions, service providers, and end users) founded in 2001. It was formed in response to increased needs for standardization of the different processes in graphic arts workflows, especially in an increasingly globalized service provider landscape. The rules of the group have been carefully conceived to ensure that the group remains practically oriented, and the priority is focused on the needs of the end users. The GWG focuses on developing best practice guidelines and specifications for graphic arts workflows. While initially focusing mainly on quality control and preflight for PDF workflows in commercial print, that focus has broadened to also include metadata specifications, workflow test suites and increased support for market segments such as packaging. All material created by the GWG is disseminated free of charge through the website of the GWG (www.gwg.org) and through the vendors and user associations partaking in the work of the group. Development happens through quarterly face to face meetings and intermediary online discussions. The mission statement of the Ghent Workgroup states that the group will “establish and disseminate process specifications for best practices in graphic arts workflows”. In practice this means that the group:

• Develops and maintains process specifications and associated documentation for best practices in graphic arts workflows.

• Develops and maintains reference implementations to ensure the specifications it develops are usable in the real world.

• Actively promotes adoption of its work in both the graphic arts user and vendor communities.

• Streamlines and coordinates the decision process between its members. While the group started its work developing guidelines for PDF quality control, it has expanded its scope. The group is now involved in magazine, office, and packaging specific specifications, the development of metadata specifications for delivering PDF files (job tickets) or proofing them, and in developing test suites to ensure workflows and applications are configured and used correctly. Most of the work of the group is done through discussions on email based forums and using virtual meetings. Four times a year, the members come together for a two-day face-to-face discussion. To streamline the work and decision process, subcommittees have been organized around specific topics do the actual work. To learn more about the different subcommittees, or to find out how you can contribute to this effort, visit the Ghent Workgroup website (www.gwg.org).


1.2 About the Ghent PDF Output Suite 4.0 In today’s complex digital prepress environments, application settings and RIP settings can have a significant effect on the end results for printed materials. The Ghent PDF Output Suite was created for users who process PDF files in the graphic arts industry, as an aid to determine whether their workflows are behaving conforming the PDF/X standards. The suite consists of a series of PDF patches that can be used by end users of graphic arts equipment as well as developers of applications that handle PDF files. Each patch tests a specific property of a PDF/X file. The patches can be used on their own, but the intention of the suite is that the patches are grouped together (as PDF pages would normally be grouped together within a workflow). All the issues tested by these patches are real world issues that can be found in a production environment; however, these patches do not reflect normal production files and the results may in some cases appear extreme. The patches have been carefully constructed to allow effects that are normally subtle to be seen clearly and unambiguously and this should be taken into account when evaluating the results of any tests based on these patches. On a technical note, all the patches found within the Ghent PDF Output Suite 4.0 conform to either the PDF/X-1a, PDF/X-3 or PDF/X-4 ISO standard, but they do not always conform to the Ghent Workgroup PDF/X-Plus specifications. It is likely that this suite will be updated, new patches will be added, and existing patches will be revised. For this reason the documentation for each individual patch is distributed along with the patch. It is advised to check regularly for updates to the suite on the Ghent Workgroup website at http://www.gwg.org.

1.3 About This Document The purpose of this whitepaper is to provide a summative overview of the Ghent PDF Output Suite 4.0, providing explanations of the patches, and to suggest ways in which these patches might be used. This document also contains a case study of how one organization used this suite to standardize RIP and application settings across several file creators and printers to create a national standard for digital ad submissions for magazine publishing..

1.4 More Information The GWG website contains a wealth of information regarding the GWG, its specifications, suites and other deliverables. There is information and tools that and cater to vendors, associations and end-users alike. It also features a user forum where you can interact with your peers and ask questions.


2 The Ghent PDF Output Suite 4.0 2.1 What is the Ghent PDF Output Suite 4.0?

The Ghent PDF Output Suite consists of several carefully designed PDF patches that can be used as an aid to determine whether print production workflows are behaving and conforming to PDF/X standards. The PDF patches can be used on their own but the intention of the suite is that the patches are grouped together. The Ghent PDF Output Suite 4.0 currently contains 35 individual PDF patches that test the behavior of 15 different properties of PDF/X files to determine whether application and RIP settings produce the desired outcome on the final printed product. The properties tested by these PDF patches are:

1. CMYK overprint 2. Spot overprint 3. Gray and black overprints 4. White overprint 5. Font Substitution 6. Shading 7. DeviceN Support 8. Font support 9. White overprint and knockout 10. Optional content (layers) 11. Soft masks 12. Basic transparency 13. File compression 14. 16-bit images 15. DeviceN overprint In addition, the output suite also contains a PDF file that organizes and combines 32 of the individual patches into 4 A4 pages for simplified testing of PDF/X-4 compliancy. It is likely that the Ghent PDF Output Suite will be updated over time, with additional PDF patches added, and existing patches revised. While this document provides a summative overview of the suite at the time of release, it is recommended that users always refer to the website (gwg.org) for the latest release of the suite, and refer to the documentation provided with each patch to note and additions and/or changes. Currently the Ghent Workgroup only supports CMYK workflows; therefore, this version of the Ghent PDF Output Suite does not contain any patches for testing device-independent workflows with ICC-based colours. The Ghent Workgroup is currently investigating best practices for device independent workflows, and there are plans to release patches to address device independent workflows in the future.


2.2 Why a New Output Suite? The Ghent PDF Output Suite 4.0 was released to provide updated support for new standards and properties supported by those standards. In particular, version 4 of the output suite provides patches that can be used to test PDF/X-4 conformity. This coincides with the recent release of GWG 2012 CMYK specifications that are based on the PDF/X-4 standard.

2.3 Comparison with the Ghent Output Suite 3.0 The Ghent PDF Output Suite 4.0 has seen a significant enhancement of version 3.0 to enable the suite to test properties that are specific to the PDF/X-4 standard. In addition to most of the existing patches from version 3.0, additional patches have been added to test typical properties introduced with PDF/X-4 (ISO 15930-7) like transparency, 16bit images, JPEG2000 compression, OpenType, etc.

2.3.1 Patch withdrawals The following 9 patches of the Ghent PDF Output Suite V3.0 have been removed:

• GWG 7.0 – 7.2 (Output Intents) • GWG 11.0 (Use of Default CMYK colour space) • GWG 10.1 + 10.2 (Spot to CMYK conversions) • GWG 13.0 – 13.2 (Color Management) These patches will become part of the planned Ghent PDF Colour Test Suite V1.0.

2.3.2 Patch updates The following 6 patches have been updated:

• GWG 3.0 (Gray Overprint): prevent ghosting effect • GWG 3.1 (Gray Image Overprint): ICC variant removed • GWG 5.1 + 5.2 (Font subset and substitution): wrong registration color fixed • GWG 8.1 (DeviceN Support (5C)): spot color inconsistency with other patches fixed • GWG 12.0 (White Overprint/Knockout): prevent ghosting effect

2.3.3 New Patches 18 new patches have been added to the Ghent PDF Output Suite in version 4.0 in order to allow checking for PDF/X-4 compliancy and DeviceN overprinting.


3 Using the Ghent PDF Output Suite 4.0 3.1 How Can You Use the Ghent PDF Output Suite 4.0?

As mentioned earlier, the Ghent PDF Output Suite 4.0 was released to provide updated support for new standards and properties supported by those standards. In particular, version 4 of the output suite provides patches that can be used to test PDF/X-4 conformity. Whether you are a file producer, printer, or prepress specialist, you can use the Ghent PDF Output Suite 4.0 to test to obtain and maintain predictable and consistent output when PDF/X-4 files are used for production. Whether you are a veteran is using Ghent Output Suites, or you are a first time user, this output suite provides you with tools to ensure your job will be output correctly. The output suite contains 35 individual PDF patches. Each patch has been developed in such a way as to test specific properties of PDF/X files, and to provide easily identifiable outcomes. In the example below we see patch GWG 3.0 that is used to test black and grey Overprint. When the patch is rendered correctly, none of the patches contains an “X”. When the file is rendered with the incorrect overprint rules applied, the affected patches will contain a clearly visible “X”.

The patches in the test suite can be used individually to test for specific issues, however the intent of the suite is such that multiple patches are grouped together and used at the same time. The output suite can be helpful to ensure that application settings are correct. For example, if you open the PDF patch above in Adobe Acrobat Pro and you see the grey “X” in the boxes as above, there is a strong likelihood that Acrobat’s “Simulate Overprinting” function is not active. If you are viewing PDF files in Acrobat without simulating overprint, there is a chance that what you are seeing on screen is not representative of what will print. On the workflow side, if the same patch shown above is RIPped and the output shows incorrect rendering, there can be several issues. It may be that you are not RIPping the file using a native PDF interpreter, or the prepress workflow is set to flatten the PDF file. Maybe the overprint settings (e.g. overprint threshold) may have to be adjusted. By using the Ghent PDF Output Suite 4.0 to test the parameters and settings in applications and RIPs you can verify or adjust settings to produce optimal results when running PDF/X files.

Patch GWG 3.0 Correctly Rendered Patch GWG 3.0 Incorrectly Rendered


3.2 Which Patches Test What? The table below demonstrates which patches should be used to test various properties. As mentioned previously, the output suite also includes a 4-page A4 sized document that includes 32 of the most relevant patches grouped together for easy testing.

Test Properties and Correlating Ghent PDF Output Suite 4.0 Patches

Property to be Tested Patches to Include

Overprinting and Knockouts

Patch 1.0 — CMYK Overprint Test Patch 1.1 — CMYK Overprint Mode Patch 2.0 — Spot to CMYK Overprint Patch 3.0 — Gray Overprint Patch Patch 3.1 — Gray Image Overprint (CMYK over Spot) Patch 4.0.1 — White Overprint Patch Patch 4.1 — White Overprint Mode Patch 12.0 — White Overprint/Knockout Patch 19.0 – DeviceN Overprint (Black) Patch 19.1 – DeviceN Overprint (Yellow) Patch 19.2 – DeviceN Overprint (White)

Fonts

Patch 5.0 — Font Substitution Patch 5.1 — Font Subset and Substitution (1) Patch 5.2 — Font Subset and Substitution (2) Patch 9.0 — Font Support Patch 9.1 — OpenType Font Support

Shading/Drop Shadows Patch 6.0 — Use of Shadings (1) Patch 6.1 — Use of Shadings (2)

DeviceN Support

Patch 8.01 — DeviceN Support (6 colors) Patch 8.1— DeviceN Support (5 colors) Patch 8.2 — DeviceN Support (4 colors) Patch 19.0 – DeviceN Overprint (Black) Patch 19.1 – DeviceN Overprint (Yellow) Patch 19.2 – DeviceN Overprint (White)

Transparency/Soft Masks

Patch 16.6 – Image Softmasks (DeviceCMYK) Patch 16.8 – Vector Softmasks (Part 1) Patch 16.9 – Image Softmasks (Part 2) Patch 16.10 – Text Softmasks (Part 1) Patch 16.11 – Text Softmasks (Part 2) Patch 16.0 – Transparency Basic Blend Modes (DeviceCMYK, Non-Knockout) Patch 16.1 – Transparency Basic Blend Modes (DeviceCMYK, Knockout) Patch 16.2 – Transparency Basic Blend Modes (DeviceCMYK, Isolated)

Optional Content (Layers)

Patch 15.0 – Optional Content (OCCD) Patch 15.1 – Optional Content (RBGroup) Patch 15.2 – Optional Content (OCMD)

16-bit Images Patch 18.1 – 16Bit Image (DeviceCMYK)

Compression Patch 17.0 – JPEG2000 compression (DeviceCMYK) Patch 17.3 – JBIG2 compression

For more information regarding the Ghent PDF Output Suite 4.0 patches, please refer to the ReadMe files included with each individual PDF patch (www.gwg.org).


4 Conclusion and Further Information 4.1 Conclusion

The Ghent PDF Output Suite 4.0 is a major revision to the Ghent PDF Output Suite 3.0. The patches contained within this latest version address and test properties of PDF/X files, including PDF/X-4. This suite should be of interest to anyone producing PDF/X files, as well as anyone that processes PDF/X files in preparation for print. Currently the test suite only focuses on DeviceCMYK; however, the GWG is currently investigating best practices around device independent workflows and it is plausible that patches will be added in the future that address ICC-based device independent workflows.

4.2 Further Information You can find more information on the work of the Ghent Workgroup and on using the PDF Output Suite 4.0 to test PDF/X conformance on the Ghent Workgroup website: www.gwg.org. You can also get in touch with someone at the Ghent Workgroup via the online form found under the contact area of the website. Here you can ask specific questions and get feedback. Further information on PDF/X standards can be found on the ISO website (http://www.iso.org). For best results, search the keyword: PDF/X.


5 Case Study: Using the Ghent PDF Output Suite 4.0 to conform to a National Standard for Digital Magazine Ad Submission The following case study explains how Magazines Canada used the Ghent PDF Output Suite 4.0 as part of there testing and conformance validation process when deciding whether or not to endorse PDF/X-4 as their preferred format for digital ad submissions For all Canadian Magazines.

5.1 About Magazines Canada Magazines Canada is the national trade association representing Canadian-owned, Canadian-content consumer, cultural, specialty, professional and business media magazines. French and English member titles offer a wide range of topics including business, professional, news, politics, sports, arts and culture, leisure, lifestyle, women

and youth, made available on multiple platforms. The association focuses on government affairs, services to the advertising trade, circulation marketing and the development of career skills for and the recognition of excellence among the people who work in Canada's magazine media (http://www.magazinescanada.ca/resources/about_us).

5.2 The Challenge Magazines Canada produces and maintains the digital Magazine Advertising Canadian Specifications (dMACS), a set of requirements that govern how digital ads are supplied to Canadian magazine publishers (dMACS Specifications). The dMACS has supported PDF/X as trusted and reliable file format for submission of digitally supplied ad materials for Canadian Magazines for several years; however dMACS required that only PDF/X-1a files be used for this purpose. While this format proved very effective; it can also be problematic when files that contain native transparency must be flattened to conform to the PDF/X-1a standard. The Manufacturing and Technical Standards Advisory Group (MTS) is a sub-component of Magazines Canada. The Manufacturing and Technical Standards Advisory Group’s mandate is to explore leading edge, business-based manufacturing and technology issues, opportunities, specifications and industry standards which help to increase internal and external production-based efficiencies. In 2013, the MTS agreed that it was time to explore alternatives to PDF/X-1a as the required file format for digital ad submission. The MTS mandated the formation of the PDF/X-4 Pilot Workgroup to determine whether or not Magazines Canada should endorse PDF/X-4 as the required format for Digital ad submission for ad materials being submitted to Canadian magazine publishers.


5.3 The Process The members of the PDF/X-4 Pilot Workgroup were carefully selected to ensure that there was representation from different facets of the industry: Content (ad) creators, magazine publishers, printers, and education. The group decided that in order for it to endorse PDF/X-4 as the new standard for digital ad submission, it would have to be confident that complex PDF/X-4 files could be processed with the same (or better) consistency and reliability across multiple printer/publisher sites as the current PDF/X-1a standard. The Workgroup discussed some of the most common problems they faced with regards to transparency and flattening issues using PDF/X-1a files. Then, with the assistance from students at Ryerson University, they developed a test page that represented a culmination of all these problems into one file. The students called the result “project Chrysalid”. The file produced by the students proved to be technically complex. It combined the following elements into one InDesign file:

• A CMYK Photoshop file with two spot channels • An Adobe Illustrator file with linked grayscale TIFF image, complex vector objects and dfont text objects placed in a separate layer as a Smart Object with layer blending mode set to multiply • A layered grayscale Photoshop file placed in a separate layer as a Smart Object with layer blending mode set to multiply • A box with a stroke set to 55K, opacity 29%, blending mode set to multiply • Spot colour text set using an OpenType font • Outline type with a gradient fill that starts as a spot colour and ends as CMYK, with its opacity set to 82%, placed over a CMYK box, set to 56% opacity

The file was saved out of InDesign CS6 using the PDF/X-4:2008 (which is really PDF/X-4:2010 standard). This file, along with an actual magazine page, and the 4-page, 32 patch Ghent PDF Output Suite 4.0 file were distributed to members of the workgroup. The goal was to run all six pages through each member’s perspective workflows to see if the pages rendered correctly on output. The Ghent PDF Output Suite 4.0 played an extremely important role in this test, as it would be used to troubleshoot any potential output problems.


In total, the files were run through four different workflows: two different Kodak Prinergy installations, one installation of Esko Automation Engine, and one installation of Agfa Apogee. The results of the first run were very interesting. In 3 of the 4 workflows, the pages did not output as intended using the standard workflows used in those environments. Specifically, there were issues when transparent spot colour objects were converted in-rip to CMYK, as well as significant overprint challenges. By examining the 4 output suite pages, it became apparent that the problems were not exactly the same for each test. The Workgroup decided to start changing one setting at a time in each of the perspective workflows in an attempt to determine the issues. The nature of the output suite patches made it relatively easy to pinpoint the issues, and make corrections. In the end, slight modifications to existing workflow settings produced the desired result in a repeatable fashion. Not only did the Ghent PDF Output Suite test patches render correctly, but the complex files created by the Ryerson students also rendered successfully. Further, archived job files that had been problematic when flattening to PDF/X-1a were testing using the new RIP settings and rendered without issue.

5.4 The Outcome With the assistance of the Ghent PDF Output suite 4.0 patches, the PDF/X-4 Pilot Workgroup mandated by the Manufacturing and Technical Standards Advisory Group of Magazines Canada was able to achieve desired, consistent and repeatable results using complex PDF/X-4 files rendered through four independent workflows. The Ghent PDF patches made troubleshooting rendering issues efficient, and made it possible to achieve desired results quickly. Based on the results of this testing, the PDF/X-4 Pilot Workgroup recommended that the Manufacturing and Technical Standards Advisory Group endorse PDF/X-4 as the required format for digital ad submission for Canadian magazines, and revise the dMACS to reflect this change.

5.5 Case Study Conclusion When implemented, this migration from PDF/X-1a to PDF/X-4 is anticipated to reduce the number of rendering issues for digital ads by reducing the potential for problems that stem from the need to flatten transparencies in files with complex transparency applied. As part of the implantation, the Manufacturing and Technical Standards Advisory Group will provide resources for publishers and printers that will make the transition as easy as possible. The group will also recommend the use of the Ghent PDF output Suite 4.0 as a tool to ensure proper and consistent output of PDF/X-4 files.

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