ISO 17972-4:2015
(Main)Graphic technology — Colour data exchange format (CxF/X) — Part 4: Spot colour characterisation data (CxF/X-4)
Graphic technology — Colour data exchange format (CxF/X) — Part 4: Spot colour characterisation data (CxF/X-4)
ISO 17972-4:2015 defines an exchange format for spectral measurement data of inks to provide a means to characterise spot colour inks to allow reliable printing and proofing of products that have been designed using these inks. Only isotropic (paper-like) substrates are within the scope of this part of ISO 17972 which is limited to application areas where the same ink and paper combination that has been characterised is used when printing. ISO 17972-4:2015 describes the use of a CustomResource element within the CxF framework to define a minimum and recommended set of data for exchange.
Technologie graphique — Échange des données de couleur en utilisant CxF — Partie 4: Données de caractérisation des points de couleur
General Information
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 17972-4
First edition
2015-06-15
Graphic technology — Colour data
exchange format (CxF/X) —
Part 4:
Spot colour characterisation data
(CxF/X-4)
Technologie graphique — Échange des données de couleur en
utilisant CxF —
Partie 4: Données de caractérisation des points de couleur
Reference number
ISO 17972-4:2015(E)
©
ISO 2015
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ISO 17972-4:2015(E)
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ISO 17972-4:2015(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Terms and definitions . 1
3 Symbols and abbreviated terms . 2
4 Requirements . 2
4.1 Conformance levels . 2
4.2 Characterisation chart preparation . 3
4.2.1 General. 3
4.2.2 Printed patches . 3
4.2.3 Substrate and ink identification . 4
4.2.4 Preparation of black region . 4
4.2.5 Measurements . 4
4.3 Measurement communication . 4
4.3.1 General. 4
4.3.2 Structure . 4
4.3.3 FileInformation element . 5
4.3.4 Core Resources . 5
4.3.5 CustomResources . 7
Annex A (normative) XML schema for CxF/X-4 CustomResource . 9
Annex B (informative) Examples of CxF/X-4 documents .10
Annex C (informative) CxF Core schema .11
Bibliography .12
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ISO 17972-4:2015(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 130, Graphic technology.
ISO 17972 consists of the following parts, under the general title Graphic technology — Colour data
exchange format (CxF/X):
— Part 1: Relationship to CxF3 (CxF/X)
— Part 4: Spot colour characterisation data (CxF/X-4)
The following parts are under preparation:
— Part 2: Scanner target data (CxF/X-2)
— Part 3: Output target data (CxF/X-3)
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ISO 17972-4:2015(E)
Introduction
ISO 17972 (all parts) defines methods for the exchange of measurement data and associated metadata
within the graphic arts industry and for the exchange of files between graphic arts users. It is a multi-
part document where each part is intended to respond to different workflow requirements. The goal
throughout the various parts of ISO 17972 has been to maintain the degree of flexibility required while
minimizing the uncertainty of the data exchanged.
ISO 17972-1 defines the use of the publicly available Color Exchange Format, version 3 (CxF3), for
prepress data exchange and verification.
ISO 17972-2 defines the use of a CustomResource for the creation of scanner target data.
ISO 17972-3 defines the use of a CustomResource when exchanging data from ISO 12642-1 and
ISO 12642-2, Prepress digital data exchange — Colour targets — Input data for characterization of
4-colour process printing.
Communication of printing characteristics of inks is essential in order to ensure that a printed product
has the appearance desired by a print buyer or brand manager. Traditionally, inks are thought of as
being either process inks or spot inks. The term “process inks” is used to describe a set of inks that are
frequently used in combination on a printing press (often cyan, magenta, yellow and black). Process inks
are generally characterised in combination and the measurement data for combinations of inks is the
subject of ISO 17972-3.
This part of ISO 17972 covers the use of CxF when exchanging spot colour characterisation data. There
are many proprietary formats for this communication and it is hoped that this part of ISO 17972 will
provide a more reliable means for the communication of spot colour characterisation data. It is usually
impractical to print and measure combinations of spot colour inks, and instead, each ink is characterised
in conjunction with a print substrate by means of its spectral characteristics and ink opacity.
In some cases, multiple impressions of single or multiple spot inks can be used and the details of the inks
used and the production method are not provided in this part of ISO 17972. Similarly, the way in which
an ink is produced is also outside of the scope. Information of this kind can be included using standard
CxF extension mechanisms.
The measurement data for metallic and fluorescent colours as described in this part of ISO 17972 might
not be sufficient to fully characterise these types of ink.
X-Rite Inc., the original creator of the CxF file format, claims no intellectual property rights to the
materials used in this part of ISO 17972.
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INTERNATIONAL STANDARD ISO 17972-4:2015(E)
Graphic technology — Colour data exchange format
(CxF/X) —
Part 4:
Spot colour characterisation data (CxF/X-4)
1 Scope
This part of ISO 17972 defines an exchange format for spectral measurement data of inks to provide
a means to characterise spot colour inks to allow reliable printing and proofing of products that have
been designed using these inks. Only isotropic (paper-like) substrates are within the scope of this part
of ISO 17972 which is limited to application areas where the same ink and paper combination that has
been characterised is used when printing.
This part of ISO 17972 describes the use of a CustomResource element within the CxF framework to
define a minimum and recommended set of data for exchange.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
ColorSpecification
information about the ColorValue (2.2) including its source (measurement specifications),
illuminant/observer calculation method (tristimulus specifications), and physical attributes of the
objects (2.5) (size, quantity, finish, etc.)
[SOURCE: ISO 17972-1, 3.1.1]
2.2
ColorValue
one of a number of defined colour space types that can hold values and associated information related
to that specific type of device independent colour space
[SOURCE: ISO 17972-1, 3.1.2]
2.3
CustomResources
“extensible” part of CxF3; additional information not included in the CxF3 Core about colour objects and the
file itself that is considered application specific in nature and not generally of use to all other applications
[SOURCE: ISO 17972-1, 3.1.3]
2.4
element content
XML text between the start-tag and end-tag of an element
[SOURCE: ISO 16684-1:2012, 3.2]
2.5
object
used to identify each specific “colour item” that is being described
[SOURCE: ISO 17972-1, 3.1.5]
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ISO 17972-4:2015(E)
2.6
resources
information about each colour object that is of interest to all readers of the CxF file
Note 1 to entry: This is also referred to as the “CxF3 Core”. It is defined by the CxF3-Core namespace schema.
[SOURCE: ISO 17972-1, 3.2.4]
2.7
schema
XML document conforming to the specifications established by the World Wide Web Consortium, that
defines the structure of a class of XML documents
[SOURCE: ISO 17972-1, 3.2.5]
2.8
spot colour
non-process colour that is used in addition to, or in place of, a process colour and is normally applied
with a single impression
2.9
tint value
value usually in the range 0 to 1 that indicates how much of a marking substance (e.g. ink, toner) should
be applied to a printed region
Note 1 to entry: This is often referred to as tone value.
2.10
XML
eXtensible Markup Language
set of rules for encoding documents electronically
[SOURCE: ISO 17972-1:2015, 3.2.6 modified]
3 Symbols and abbreviated terms
The following documentation conventions are used.
— Names of XML elements are shown in bold type, for example, Resources.
— Names of XML attributes are shown in italics, for example, SpotColorName.
— XML XPaths are used to identify XML elements. For example, container/contained refers to an
element (contained) that is a child of another element (container).
— Similarly, XML XPaths are used to refer to XML attributes, for example, element1/@Name refers to
an attribute (Name) of an element (element1).
4 Requirements
4.1 Conformance levels
This specification defines three conformance levels identified as CxF/X-4, CxF/X-4a and CxF/X-4b. These
conformance levels allow different methods of spot colour communication in common use to be described.
a) CxF/X-4 Full Characterisation. The data provided by CxF/X-4 allows the colour and opacity of the
ink to be specified. This is particularly important in situations where an accurate proof of the spot
ink printed on top of other content is to be made.
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ISO 17972-4:2015(E)
b) CxF/X-4a Single Background Characterisation. There are situations where it is useful to be able
to communicate characterisation data for an ink where the ink will only be printed on a single
background and so can be characterised using a single set of spectral measurements.
c) CxF/X-4b Single Patch Characterisation. There are situations where it is useful to be able to
communicate characterisation data for an ink where the ink will always be printed as a solid and so
can be characterised using a single spectral measurement.
4.2 Characterisation chart preparation
4.2.1 General
Measurement data in a conforming CxF/X-4 file should be taken from a spot ink characterisation chart
as shown in Figure 1. This measurement data provides the characteristic colour response for the
combination of ink and substrate.
12
h
2
w
3
Key
1 solid
2 substrate
3 region printed with black
Figure 1 — Example characterisation chart
4.2.2 Printed patches
For all conformance levels, patches of 0 % and 100 % shall be printed on the unmarked substrate.
The printing system to be characterised shall be suitably configured and calibrated to match normal
operating conditions before the characterisation chart is printed.
Tint levels recorded in the CxF data shall be those requested by the characterisation chart, which is not
guaranteed to match the percentage area covered on the print because of tone value increase or other factors.
Tint levels recorded in the CxF data shall be as percentage values in the range of 0 to 100, where 0 m
...
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