storing processing step data in pdf - ghent workgroup · 2016. 5. 13. · iso standard iso 19593-1...

Storing Processing Step Data in PDF

Authors Lieven Plettinck Esko [email protected] Date 12 May 2016 Status GWG version

[email protected] www.gwg.org

Processing Steps Data in PDF

Table of Contents 1 Introduction ................................................................................................. 3 1.1 Types of Processing Step Data ........................................................................ 4 1.2 Why are Processing Step Data embedded in PDF? ............................................. 7 2 How to store Processing Step Data in PDF? ...................................................... 9 2.1 Processing Step OCGs.................................................................................... 9 2.2 Coloring and Positioning of Processing Step Objects ......................................... 13 3 Example ..................................................................................................... 14


1 Introduction It is common practice in the packaging and other segments of the printing industry industry to add additional objects and metadata in a PDF that will not be used for printing the final product e.g. cut lines. This data corresponds to additional processing steps (e.g. die cutting). At this point in time, the method used to store these objects in the PDF is not standardized. As a consequence multiple methods are used depending on the application used to generate the PDF and the preferences of the user. For example, in 1 PDF the cut line can be stored in a layer called “CAD” using a contour with a stroke in spot color “coupe”, while in another PDF the cut line is stored in the same layer as the graphics and is represented as a contour with a stroke in spot color “cut”. This lack of standardization leads to problems of interoperability between companies and systems. Suppose, for example, a converter (the packaging equivalent of a printer) has configured its RIPs to ignore “cut” inks in incoming PDF files. If he the converter now receives a PDF with an ink “coupe”, he risks wasting an extra plate. This document describes a standardized method for storing data (objects and metadata) corresponding to additional processing steps in a PDF. Warning: This specification has been submitted to ISO for standardization. At the time of writing, the ISO standardization process is not finalized. As a consequence the final ISO standard ISO 19593-1 may deviate from this document. Implementers are strongly advised to base their work on the ISO documents.


1.1 Types of Processing Step Data Below is a non-exhaustive list of processing steps PDF objects.

1.1.1 Structural Data (CAD) A collection of contours in the PDF document that describe how the label or package will be finished (cut, folded, glued, embossed…) to produce the 3D end product from the flat substrate. These lines correspond to operations performed on finishing devices like die cutters, folder-gluers, etc…

1.1.2 Braille Braille text is applied to packaging after printing. Usually this is done by a die cutter (for a complete sheet of printed boxes), a folder/gluer (for single boxes) or inkjet device.


1.1.3 Legend Informational panels containing job data e.g. design identification, customer info, technical details…etc. positioned outside the die line.


1.1.4 Dimensions A collection of indications (arrows, numbers and units) of sizes of items in the design.

1.1.5 Positions Indications of intended or allowed positions for text, barcodes, holograms, etc.

1.1.6 White

Processing step data indicating application of white backing ink, such as might be used on transparent or metallic substrates.


1.1.7 Varnish Varnish processing step data is a collection of PDF objects indicating application of varnish after printing.

1.2 Why are Processing Step Data embedded in PDF? A PDF can serve as a container for all production data, printing and non-printing, of a package or label. The PDF is enriched with structural data, data for special finishing and extra information for QC and approval.

1.2.1 Correct placement of graphics in relation to structural data of the 1-up The primary purpose of having structural data in the PDF is to give the graphic designer (creative designer or production artist) a context for correct placement of graphic elements.

1.2.2 QC Quality Control (QC) and approval • Structural data

o Structural data are embedded in PDFs to enable verification that the correct die shape was used and graphic elements were correctly placed relative to the structural contours.

o QC applications like Adobe Acrobat allow showing/hiding the structural contours. o Structural data contours are usually printed on hard copy proofs made for QC and

approval purposes. • Braille is included in the PDF using an artificial spot color to make it visible for non-

visually impaired QC people. • Legends and dimensions are added to give extra context and information to the QC and

approval people.


1.2.3 Layout and tool manufacturing • The structural data embedded in the 1-up PDF is used by automated layout applications

to fill a sheet or web with correctly placed 1-ups. • This can be a layout of graphics on a sheet or web to correspond with an analog die

(e.g. folding carton and labels). This can also be an optimized nesting algorithm to minimize material waste for digital finishing (e.g. cutting table or laser cut device).

• From the layout of the graphics on the sheet or web the position of the braille elements is derived to manufacture the braille dies.

• From the layout of the graphics on the sheet or web the position and shape of varnished or coated elements can be derived. Using this data ,a varnish printing plate can be made or a coating blanket can be cut.

• Idem for foils.

1.2.4 Digital finishing The structural data in the PDF can be used to drive digital finishing machines. Braille data can be extracted from the PDF to drive inkjet braille machines.


2 How to store Processing Step Data in PDF

2.1 Processing Step OCGs

2.1.1 Use of layers (OCGs) • Optional Content Groups (OCGs) are used to collect all objects belonging to the same

processing step. • A processing step OCG is an OCG with an additional GTS_Metadata key in the OCG

dictionary. The value of this key is a dictionary containing standardized identifying information.

• A processing step OCG only contains objects that belong to the processing step OCG. No other objects (printing objects or objects belonging to another OCG) are allowed.

• The name of a processing step OCG is not standardized. E.g. the name can be localized to the language of the intended users of the PDF.

2.1.2 GTS_Metadata dictionary

Key Type Value

GTS_Metadata GTS_Metadata dictionary GTS_Metadata dictionary containing keys defined below

Additional GTS_Metadata entry in an optional content group dictionary


Key Type Value

GTS_ProcStepsGroup name Group of the processing step OCG. The value of this key has to be one of the values defined in the section “Values for GTS_ProcStepsGroup” whenever there is a matching value. If there is no applicable value, a conforming writer may use a custom value. All custom values for this key shall be second class names as described in ISO 32000-1 annex E.

GTS_ProcStepsType name Type of the processing step OCG The value of this key has to be one of the values defined in the section “Values for GTS_ProcStepsType” whenever there is a matching value. If there is no applicable value, a conforming writer may use a custom value. All custom values for this key shall be second class names as described in ISO 32000-1 annex E.

Entries in a GTS_Metadata dictionary

2.1.3 Values for GTS_ProcStepsGroup GTS_ProcStepsGroup Description Structural Processing step group containing a set of

processing step objects describing finishing steps that will be applied after printing e.g. on a die cutting device, a folder-gluer etc…

Dimensions Processing step group containing a set of dimension lines and indications of size.

Braille Processing step group containing braille text. Legend Processing step group containing administrative

and technical information. Positions Processing step group containing positioning

information for various graphical and non graphical elements


White Processing step group containing a set of processing step objects describing a white backing applied on transparent foils, metallic surfaces, etc…

Varnish Processing step group containing a set of processing step objects describing printed varnish

If the list above does not contain an applicable value, a conforming writer may use a custom value. All custom values for this key shall be second class names as described in ISO 32000-1 annex E.

2.1.4 Values for GTS_ProcStepsType Processing Step Group: Structural The table below specified the defined values for the key GTS_ProcStepsType when the GTS_ProcStepsGroup key has the value /Structural. GTS_ProcStepsType Description Cutting Processing step objects indicating how the printed

artwork will be cut from the printed sheet e.g. with a guillotine cutter or die cutting device.

PartialCutting Processing step objects indicating where the substrate will be cut partially: i.e. not entirely through the material

ReversePartialCutting Processing step objects indicating where the substrate will be cut partially; i.e. not entirely through the material on the opposite side of the substrate

Creasing Processing step objects indicating where the substrate will be creased to guide subsequent folding.

ReverseCreasing Processing step objects indicating where the substrate will be creased on the opposite side of the substrate

CuttingCreasing Alternating cutting and creasing ReverseCuttingCreasing Alternating cutting and creasing on the opposite

side of the substrate PartialCuttingCreasing Alternating partial cutting and creasing Reverse PartialCuttingCreasing

Alternating partial cutting and creasing on the opposite side of the substrate

Drilling Processing step objects indicating locations where the substrate will be drilled.

Gluing Processing step objects enclosing a glue area are. Usually no ink or varnish may be applied to these areas.

FoilStamping Processing step objects enclosing an area where foil will be applied through hot foil stamping.

ColdFoilStamping Processing step objects enclosing an area where foil will be applied though cold foil stamping (i.e. using glue)

Embossing Processing step objects enclosing an area where embossing will be applied.

Debossing Processing step objects enclosing an area where debossing will be applied.


Perforating Processing step objects indicating where the substrate will be perforated.

Bleed Processing step objects indicating the intended bleed for print.

VarnishFree Processing step objects enclosing an area where no varnish should be applied.

InkFree Processing step objects enclosing an area where no printing ink should be applied.

InkVarnishFree Processing step objects enclosing an area where no printing ink and no varnish should be applied.

Folding Processing step objects indicating where the substrate will be folded without prior creasing

Punching Processing steps objects indicating the locations at which the substrate will be punched and the size and shape of the resulting holes.

Stapling Processing steps objects indicating the locations at which the substrate will be stapled or stitched, and the size of the staples or stitches to be used.

If the list above does not contain an applicable value, a conforming writer may use a custom value. All custom values for this key shall be second class names as described in ISO 32000-1 annex E. Processing Step Group: Positions The table below specified the defined values for the key GTS_ProcStepsType when the GTS_ProcStepsGroup key has the value /Positions. GTS_ProcStepsType Description Hologram Functional group containing processing step objects

that indicate the position of holograms. Barcode Functional group containing processing step objects

that indicate the position of barcodes ContentArea Functional group containing processing step objects

that indicate areas where text and other graphical elements may be placed.

CodingMarking Processing step objects specific to packaging that indicates areas where additional information not contained in the PDF will be printed on the packaging at the post-press stage, such as on filling lines where final products are being packed. Some examples of information that might be included as CodingMarking include but are not limited to best before dates, lot numbers, production dates, and tracking codes.

Imprinting Processing step objects that indicates areas where additional information (i.e. variable data) will be printed on pre-printed shells which contain the bulk of the graphical content, as a secondary print stage prior to finishing.

If the list above does not contain an applicable value, a conforming writer may use a custom value. All custom values for this key shall be second class names as described in ISO 32000-1 annex E


2.2 Coloring and Positioning of Processing Step Objects

2.2.1 Coloring and positioning of processing step objects in the Structural, Braille, Dimensions, Positions, White and Varnish processing step group • Objects in these OCGs can overlap geometrically with objects used for printing. (The

outline of the processing steps object can overlap with the outer cut shape of the package or label).

• Processing step objects are colored with a spot color (sometimes referred to as technical separations) to visualize them in viewing or proofing applications.

• Names of spot colors used to color processing step objects are not standardized. It is recommended to use the same value as the corresponding GTS_ProcStepsGroup or GTS_ProcStepsType value.

• The spot colors used to color processing step objects can’t be used to color normal printing graphical objects.

• Processing step Objects should not interact with the printing separations: that is, the presence of the processing step objects in the PDF should have no influence on the printing separations (no knock-out, no transparency blending effects, etc.).

2.2.2 Coloring and positioning of processing step objects in the Legend processing step group • There are no limitations for coloring objects in the legend functional OCG. • Objects in the legend functional OCG have to to be in an “off-bleed” area i.e. they do not

intersect the outer cut or bleed contour.


3 Example Example below illustrates the use of entries based on the GTS_ProcStepsGroup and GTS_ProcStepsType keys as defined in this document 40 0 obj << /Type /OCG /Name (Some sample layer) /GTS_Metadata << /GTS_ProcStepsGroup /Structural /GTS_ProcStepsType /ReversePartialCutting >> >> endobj

storing processing step data in pdf - ghent workgroup · 2016. 5. 13. · iso standard iso 19593-1...

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