A PDF Association Presentation · © 2016 by PDF Association · www.pdfa.org
www.pdfa.org
2016-06-15
Stephan Jaeggi, PrePress-Consulting Switzerland
2
PDF Days Europe 2016
RGB Workflow with PDF/X-4
Stephan Jaeggi PrePress-Consulting Switzerland [email protected] www.pdf-aktuell.ch
2
RGB Workflow with PDF/X-4
n Why RGB workflow? n Color transformation where? n CMYK workflow (Early Binding/Classic) n Color gamut differences n Different requirements n RGB workflow (Late Binding) n Intermediate Binding n Potential problems of ICC transformations n Problems with transparency n Transparency definition in PDF 1.4 / PDF 2.0 n GWG2015 CMYK+RGB n Guidelines
About Stephan Jaeggi
n Degree in Printing and Packaging Engineering FH/ESIG-COMEM n Manager of typesetting system, Graphische Betriebe Coop, Basel n Manager Technical IT at Swiss Printers Association, Zurich n Owner PrePress-Consulting in Binningen/Basel since 1992 n Co-author of Whitepaper «PDF for Prepress» (1998) n Technical Expert of ISO TC130/TF2/WG2 since 1998
n Definition of ISO standards 15930-1 ... 15930-8 (PDF/X) n Co-author of ISO standard 15930-3 (PDF/X-3:2002) n Certification officer of PDFX-ready Switzerland since 2005
n Recepices, settings and guidelines for the easy use of PDF/X n Preflight profiles (based on GWG specifications) n Creator, Output and Expert certifications (for users)
n Technical officer of Ghent PDF Workgroup (GWG) 2006 – 2014 n Definition of PDF/X-Plus specifications n Certification of PDF/X software (vendors) n Test files
n PDF expert (part time) at Novartis Pharma Strategic Packaging Group/Artwork Operations 2010 – 2015
Why RGB workflow?
n New printing standards n 2015: PSO Coated V3, PSO Uncoated V3 n 2017: Web offset profiles V3
n Early commitment for a printing condition can be problematic n Short term: change of paper (coated –> uncoated) n Long term: new standards, new printing techn. (Inkjet)
n Often an image shall be used for multiple medias n Multiple printing technologies
(sheetfed offset, web offset, newspaper, digital printing) n Digital publications (Internet, tablets)
The decision for the „right“ color space becomes more difficult.
Color transformation where?
Creator Printshop
§ plate making § press § paper
§ ink
CMYK workflow (Early Binding/Classic)
Creator Printshop
Color transformation
Color transformation happens without knowing the printing cond.
Color gamut differences
n Newspaper vs. digital printing
© [email protected] For each printing condition adapted images are required!
Different requirements
n Dot gain: 10% (sheetfed offset) ... 26% (newspaper) n Total ink coverage: 240% (Newspaper) ... 350% (ISO Coated)
n Statistics of dutch newspaper publishers n 40,7% of 36'600 ads had a TAC > 240%
Source: Dutch New
© [email protected] spaper Association (Cebuco)
RGB workflow (Late Binding)
Creator Printshop
Color transformation Shift of the responsability for the color transformation!
Intermediate Binding
Creator PrintshopColor transformation
© [email protected] Medianeutral RGB workflow for the creator
Potential problems of ICC transform.
n New (different) black composition in CMYK images
CMY
K
PCS
CMY
K
Potential problems of ICC transform.
n Grayscales get converted to 4C
CMY
K
PCS
CMY
K
Potential problems of ICC transform.
n
Illustration
Pure Black appears in all four process colors (screening!)
,,,,0% C ....0% M ....0% Y 100% K
..45% C
..34% M
..33% Y
..87% K PCS
of pure
PCS
n Contamination
0 / 100 / 100 / 0
: Florian Süssl, Metadesign
colors (screening!)
1 / 98 / 85 / 5 1 / 98 / 85 / 5
Problem with transparency flattening
n For transparency flattening the colors must be converted into the same color (blend) space.
n Medianeutral colors are lost!!! n Conclusion: transparency must be maintained until
the final output color space is known. n Therefore for medianeutral files with transparency
PDF/X-4 is a must!
50%
CMYK
ICC-RGB
CMYK
Deviating results
n Transparency Blend Modes
Without output preview
Ghent PDF Output Suite 4.0
With output preview
Unclear situation
n Isolated transparency groups with ICCbased colors (RGB and/or CMYK) are rendered differently!
n Reason: unclear definition in the Adobe PDF
specifications: «When necessary, backdrop and source colours shall be converted to the blending colour space before the compositing computation.»
Conclusion
n Until the new PDF 2.0 and PDF/X-6 specifications are are published and supported in the applications and output workflows, we should avoid creating PDFs with unclearly defined transparent objects.
n That means: preflight error for transparency groups with ICCbased transparency blend spaces.
n In other words: RGB images with ICC profiles are not a problem.
GWG2015 CMYK+RGB
n Based on PDF/X-4:2010 n Allowed colors
n DeviceCMYK, DeviceGray, Spot for text, vectors and images
n ICCbased RGB, Lab for images
n Not allowed n ICCbased colors
for text and vectors n ICCbased transparency
blend color spaces n …
Preflight PDF/X-4 CMYK+RGB
n Callas pdfToolbox 8.2 n EnfocusPitStop Pro 13U2
GWG 2015 preflight profiles not
© [email protected] yet available in Acrobat DC
GWG2015 PDF/X Workflow Guideline
n GWG2015 Workflow overview n The Ghent Workgroup example page n Processing PDF: Today, tomorrow and future...
n PDF and PDF/X n PDF limitations, necessary for prepress data
creation n Which GWG specification to use? n Process-specific (classic) image editing n Media-neutral image editing n Process-specific (classic) vector illustrations n Configuring layout apps: new documents
n Configuring layout appss: Existing documents n Live preflight in InDesign n Design & layout n Layout optimization using transparency n Color management:
Early, Intermediate & Late Binding n PDF/X creation n InDesign: export as PDF/X-4 CMYK n QuarkXPress: export as PDF/X-4 CMYK
n InDesign: export as PDF/X-4 CMYK + RGB
PDFX-ready Leitfaden 2016 (german) n PDFX-ready-Workflow-Überblick n Die PDFX-ready-Beispielseite n PDF-Verarbeitung – gestern, heute und morgen
n PDF und PDF/X n PDF-Varianten in der Druckvorstufe n Welchen PDFX-ready-Standard verwenden? n Bilder verfahrensangepasst aufbereiten n Bilder medienneutral aufbereiten n Grafiken verfahrensangepasst aufbereiten
n Layoutprogramm konfigurieren n Preflight im Layoutprogramm n Layout aufbauen n Transparente Layouts optimieren n Farbmanagement n PDF/X-Erzeugung: InDesign und Xpress
n PDF Preflight n Warum PDFX-ready V2? n Der PDFX-ready-Qualitätsstandard n Umgang mit dem PDF/X-Output-Intent n Farben im PDF anpassen: warum und wie? n PDFX-ready V2-Verarbeitung n PDFX-ready V2-Anpassungworkflows
Use case: Endress+Hauser
n Product literature created by Marketing with InDesign n Images of products in AdobeRGB in high quality n Other images in multiple CMYK color spaces
n Two PDF/X workflows n PDF/X-4 CMYK+RGB for contracted printshops n PDF/X-1a CMYK for local printshops
n Preflight profiles based on PDFX-ready
Two workflows
Customer Printshop
Contracted printshops
PDF/X-1a
PDF/X-4
© [email protected] Combination of advantages of both workflows. Local printshops
Summary
n Advantages of medianeutral data exchange n Independent of output (printing condition, new media) n Flexibility (change of printing condition on short notice) n No unnecessary loss of information (color gamut) n Consistent color conversion for all images in a print job
n Medianeutral data definition requires PDF/X-4 n Medianeutral color definition with ICCbased RGB is
only useful for images at the moment n Text and vectors should still be defined in CMYK n CMYK image should be placed as DeviceCMYK to
avoid unnecessary color transformations
Medianeutral is not suitable for all print jobs.
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