Graphic technology — Exchange format for colour and process control data using XML or ASCII text

This document defines an exchange format for colour and process control data (and the associated metadata necessary for its proper interpretation) in electronic form using either XML or ASCII formatted data files. This exchange format maintains human readability of the data as well as enabling machine readability. It includes a series of predefined tags and keywords, and provides extensibility through provision for the dynamic definition of additional tags and keywords as necessary. It is focused primarily on spectral measurement data, colorimetric data, and densitometric data. This document is intended to be used in conjunction with other standards that will define the required data, and tags or keywords for specific data exchange applications.

Technologie graphique — Format d'échange pour les données de couleur et de contrôle de procédé en utilisant du texte XML ou ASCII

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Published
Publication Date
07-Sep-2022
Current Stage
6060 - International Standard published
Due Date
08-Dec-2023
Completion Date
08-Sep-2022
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INTERNATIONAL ISO
STANDARD 28178
Second edition
2022-09
Graphic technology — Exchange
format for colour and process control
data using XML or ASCII text
Technologie graphique — Format d'échange pour les données de
couleur et de contrôle de procédé en utilisant du texte XML ou ASCII
Reference number
ISO 28178:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 28178:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 28178:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Requirements .......................................................................................................................................................................................................... 2

4.1 General description of a conforming file ......................................................................................................................... 2

4.1.1 XML format .............................................................................................................................................................................. 2

4.1.2 ASCII format ........................................................................................................................................................................... 2

4.2 Tags and keywords ............................................................................................................................................................................. 3

4.2.1 General ........................................................................................................................................................................................ 3

4.2.2 Required preamble tags and keywords ......................................................................................................... 4

4.2.3 Optional tags and keywords .................................................................................................................................... 6

4.2.4 User-defined tags and keywords ...................................................................................................................... 11

4.2.5 Data format identifier .................................................................................................................................................12

4.3 Data tables ............................................................................................................................................................................................... 12

4.3.1 General .....................................................................................................................................................................................12

4.3.2 Table descriptor ...............................................................................................................................................................12

4.3.3 Table name ............................................................................................................................................................................ 12

4.3.4 Data format identifiers............................................................................................................................................... 13

4.3.5 Table data ............................................................................................................................................................................... 16

Annex A (informative) Advantages of an XML data reporting format ..........................................................................17

Annex B (informative) Tag and keyword examples .........................................................................................................................19

Annex C (informative) Sample files ....................................................................................................................................................................24

Annex D (informative) Example of use of user-defined keywords ...................................................................................30

Bibliography .............................................................................................................................................................................................................................37

iii
© ISO 2022 – All rights reserved
---------------------- Page: 3 ----------------------
ISO 28178:2022(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

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

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 of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 130, Graphic technology.

This second edition cancels and replaces the first edition (ISO 28178:2009), which has been technically

revised.
The main changes are as follows:

— in 4.2.3.21, an additional tag to remove ambiguity with respect to the printing sequence and the

sequence of tabulating data in particular to ease the data exchange for multi-colour printing has

been added;

— in 4.1.2.1, additional guidance on the use of delimiters, such as point and comma, as well as the

plausibility of the sample ID usage have been provided.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2022 – All rights reserved
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ISO 28178:2022(E)
Introduction

This document is intended to support all existing and future graphic arts standards that require the

exchange of measured, computed, or process control data and the associated metadata necessary for its

proper interpretation.

The following requirements were identified when reviewing the needs of such a format:

— applications based on the existing ASCII formats must not be made obsolete;

— data must be in a form that is both human-readable (once the digital file has been displayed using

standard editors, or file readers) and machine-readable;

— data must be readable by automated programs to extract the necessary information;

— data files must be extensible by end users in such a way as to allow additional information to be

included without breaking automated readers of the file;
— data files must be capable of being created by automated programs;
— the format must allow multiple language representation of data.

The file formats chosen to accomplish this task are a combination of XML and extensions of the existing

ASCII keyword-value file format, coupled with the necessary tools to allow appropriate conversions

to and from XML from ASCII keyword-value files. However, either the XML file format or the ASCII

keyword-value file format can be used independently.

These formats make use of predefined XML tags and ASCII keywords. Values are associated with the

tags and keywords and remain in effect until another instance of the tag or keyword. Provision is

made to allow the use of data tables and to separately define the format within data tables. Multiple

occurrences of such data tables within a single file are also permitted. User-defined tags and keywords

are also allowed.

NOTE During the 2021 review process, it was noted that the XML format is not widely used and that its

specification in this document is insufficiently precise to ensure reliable exchange of data.

© ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 28178:2022(E)
Graphic technology — Exchange format for colour and
process control data using XML or ASCII text
1 Scope

This document defines an exchange format for colour and process control data (and the associated

metadata necessary for its proper interpretation) in electronic form using either XML or ASCII

formatted data files. This exchange format maintains human readability of the data as well as enabling

machine readability. It includes a series of predefined tags and keywords, and provides extensibility

through provision for the dynamic definition of additional tags and keywords as necessary. It is focused

primarily on spectral measurement data, colorimetric data, and densitometric data.

This document is intended to be used in conjunction with other standards that will define the required

data, and tags or keywords for specific data exchange applications.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
data format identifier

predefined set of characters, without intervening spaces, forming a unique word that is used to identify

the presence of a defined item of data in a subsequent data table
3.2
keyword

predefined set of characters, without intervening spaces, forming a unique word that is used to identify

the presence of a defined item of information
3.3
schema

XML document that, following the rules established by the World Wide Web Consortium, defines the

structure of a class of xml documents
3.4
value

information immediately following a keyword (3.2) that represents the data content or "value"

associated with that keyword
© ISO 2022 – All rights reserved
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ISO 28178:2022(E)
4 Requirements
4.1 General description of a conforming file
4.1.1 XML format
[46]

This file format is an XML format that complies with Extensible Markup Language (XML) 1.0. The

format makes use of predefined tags that identify information commonly used to describe graphic arts

samples. In addition, users of this format are allowed to define tags to tailor the format to their specific

needs according to the rules of XML namespace.
The data file is divided into two sections.

The preamble is the first section. This section provides general information and describes the conditions

under which data was collected. The preamble tag is iso28178.preamble. Tags used in the preamble are

listed in 4.2.

The data section is the second section, which is further divided into two parts. The first part of the data

section provides the information that describes the type and location of the table contents; the second

section contains the data values.

The schema associated with the XML format defined in this document is contained in file iso28178_

data.xsd (available at: https:// standards .iso .org/ iso/ 28178/ ed -2/ en/ ), which is an essential normative

part of this document. This document also provides structural XML tags that are needed for the proper

specification of an XML document instance.

NOTE See Annex A for a discussion on the need and application of the XML data reporting format.

4.1.2 ASCII format
4.1.2.1 General

This file format is an ASCII format keyword-value file. It makes use of predefined keywords and data

tables. Values are associated with the keyword that precedes them and remain in effect until another

instance of the keyword-value pair. Data values are delimited by the BEGIN_DATA and END_DATA

keywords.

Keywords and values, as well as fields within data tables, are separated by white space. Valid white

space characters are space (position 2/0 of ISO/IEC 646), carriage return (position 0/13 of ISO/IEC 646),

newline (position 0/10 of ISO/IEC 646), and tab (position 0/9 of ISO/IEC 646). Keywords may be

separated from values using any valid white space character. Only the space and tab may precede a

keyword on a line. Comments are preceded by a single comment character (a single character keyword).

The comment character is the "#" (position 2/3 of ISO/IEC 646) symbol. Comments may begin any place

on a line, and are terminated by a newline or carriage return character.

NOTE The default separator for exporting data from spreadsheet applications in many regions is a comma

and not a white space character. Conforming files can be created by changing this default to a tab character and

by using the full point character as the decimal separator.
4.1.2.2 Exchanged data file structure

A file containing measurement data would normally be structured as shown in Figure 1. This structure

allows multiple tables of data within a single exchange file.
© ISO 2022 – All rights reserved
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ISO 28178:2022(E)
Figure 1 — File structure
4.2 Tags and keywords
4.2.1 General

Most tags and keywords may appear in the file in any order, and may appear multiple times within

the file. Values associated with tags and keywords that appear more than once shall be replaced by

successive instances except for KEYWORD, COMPUTATIONAL_PARAMETER, and WEIGHTING_

FUNCTION. Tags and keywords that describe data tables, however, shall be defined before the data

table. Table 1 lists these tags and keywords. These tags are described in greater detail in this subclause.

Table 1 — XML tags and ASCII keywords that appear in a defined order
Function XML tag ASCII keyword
data table width NUMBER_OF_FIELDS
data format delimiters BEGIN_DATA_FORMAT
END_DATA_FORMAT
data table length NUMBER_OF_SETS
data table delimiters BEGIN_DATA
END_DATA

Data format delimiters shall be preceded by a data table width tag or keyword. Data table delimiters

shall be preceded by a data table length tag or keyword. In the ASCII format, BEGIN_/END_ keywords

begin and end the data format or table data. In the XML format, tags have parameters and/or values and

© ISO 2022 – All rights reserved
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ISO 28178:2022(E)

a standard syntax is used; e.g. data format identifiers . Values for tags

and keywords that describe data tables shall be specified for each data table in the file; i.e. inheritance

of these values is not permitted.

ASCII tags and keywords may be composed of any combination of the following: upper case letters;

digits 0 through 9; and ASCII characters $ (position 2/4 of ISO/IEC 646), % (position 2/5 of ISO/IEC 646),

& (position 2/6 of ISO/IEC 646), - (position 2/13 of ISO/IEC 646), / (position 2/15 of ISO/IEC 646), _

(position 5/15 of ISO/IEC 646). By convention all XML tags are lower case.

In the ASCII format, unless used as part of a data format definition, keywords should not be preceded

on a line by other than white space. Unless otherwise noted, each keyword has a character string value

associated with it. All character string values shall be enclosed in quotes, regardless of whether there is

white space contained within the string. Enclosed in quotes means beginning and ending the character

string with the " symbol (position 2/2 of ISO/IEC 646). The " symbol itself is represented within a string

as "" as in the C language syntax.

NOTE The default behaviour of applications writing '.csv' files results in additional quotation marks being

added to files, for example "FILE_DESCRIPTOR ""12642-3 Target definition""", which means that such files do not

conform with this requirement.

For XML tag/keyword entries the form is value. If attribute names are provided

in the XML section of a definition, the information is represented in the XML-formatted data as XML

attribute using the form .

The value associated with keywords NUMBER_OF_FIELDS and NUMBER_OF_SETS shall be an integer.

These values should not be enclosed in quotes.

Format and table delimiters do not have explicit values associated with them but rather enclose either

the data format definition or table data.

The separation between the integer and the fractional part of a given number should be a "full point"

for all entries.

See Annex B for examples of the use of each tag and keyword shown in 4.2.2 and 4.2.3.

4.2.2 Required preamble tags and keywords
4.2.2.1 General

Certain tags and keywords are required as part of each file, while others are optional depending upon

the data to be included. All keywords shall occur before the BEGIN_DATA_FORMAT keyword and the

sequence order for required tags and keywords shall follow the order shown in 4.2.2.2 through 4.2.2.9.

The STANDARD, ORIGINATOR, FILE_DESCRIPTOR and CREATED tags/keywords may occur only once

within a file.

The first line in the ASCII format should be ISO 28178. The use of this identifier indicates that the data

contained in the file adheres to this document. This information is represented in the XML format with

the tag. See 4.2.2.2.

NOTE Strings are widely used including "ECI2002", "CGATS17", "CGATS.17", "ISO 12642-2". These files often

conform to this document with the exception of this identifier.
4.2.2.2 Standard

The use of this identifier indicates that the data contained in the file adheres to the indicated standard.

Format Tag/Keyword Attribute Data type
XML String
© ISO 2022 – All rights reserved
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ISO 28178:2022(E)

NOTE There is no ASCII keyword for this because in the ASCII format this information is carried in the first

line of the file.
4.2.2.3 Originator

Identifies the specific system, organization or individual that created the data file.

Format Tag/Keyword Attribute Data type
XML String
ASCII ORIGINATOR String
4.2.2.4 File descriptor
Describes the purpose or contents of the data file.
Format Tag/Keyword Attribute Data type
XML String
ASCII FILE_DESCRIPTOR String
4.2.2.5 Created

Indicates the creation date of the data file. The recommended form for this date is CCYY -MM -DDThh:

mm: ss[Z | +/-hh:mm].
Format Tag/Keyword Attribute Data type
XML String
date String
ASCII CREATED String
4.2.2.6 Number of fields

Number of fields (data format identifiers) that are included in the data format definition that follows.

Format Tag/Keyword Attribute Data type
XML Integer
ASCII NUMBER_OF_FIELDS Integer
4.2.2.7 Data format

Marks the beginning and end of a data format definition. END_DATA_FORMAT shall be preceded by

BEGIN_DATA_FORMAT. See 4.3.4 for information on the data that would be included between these

tags/keywords.
Format Tag/Keyword Attribute Data type
XML NA
ASCII BEGIN_DATA_FORMAT
END_DATA_FORMAT
© ISO 2022 – All rights reserved
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ISO 28178:2022(E)
4.2.2.8 Number of sets of data

Number of repetitions or sets of data, i.e. the number of rows in the data table. The associated value is

an integer.
Format Tag/Keyword Attribute Data type
XML Integer
ASCII NUMBER_OF_SETS Integer
4.2.2.9 Data table
Marks the beginning and end of a data table.
Format Tag/Keyword Attribute Data type
XML
NA
ASCII BEGIN_DATA
END_DATA
4.2.3 Optional tags and keywords
4.2.3.1 General

Certain additional general tags and keywords are optional and may be used as needed. The currently

defined optional tags and keywords are defined in 4.2.3.2 to 4.2.3.19. The optional tags and keywords

shall occur after the CREATED tag/keyword and before the NUMBER_OF_FIELDS tag/keyword.

4.2.3.2 Comment

Comments are ignored by automated readers. In the XML syntax, all characters within the

tags are ignored. In the ASCII syntax, all characters between the comment keyword and

the end of line indicator are ignored. End of line is indicated by either carriage return or newline.

Comments indicate to users that the information that follows is of informative interest. Comments need

not be enclosed in quotes. Comments may occur anywhere except within a table.
Format Tag/Keyword Attribute Data type
XML String
ASCII # String
4.2.3.3 Instrumentation

Used to report the specific instrumentation used (e.g. manufacturer, model number and serial number,

etc.) to generate the data reported. This data will often provide more information about the particular

data collected than an extensive list of specific details. This is particularly important for spectral data

or data derived from spectrophotometry.
© ISO 2022 – All rights reserved
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ISO 28178:2022(E)
Format Tag/Keyword Attribute Data type
XML String
manufacturer String
model String
serial_number String
ASCII INSTRUMENTATION String
4.2.3.4 Measurement geometry

The type of measurement, either reflection or transmission, should be indicated along with details

of the geometry and the aperture size and shape. For example, for transmission measurements it is

important to identify 0/diffuse, diffuse/0, opal or integrating sphere, etc. For reflection measurements

it is important to identify 0/45, 45/0, sphere (specular included or excluded), etc.

Format Tag/Keyword Attribute Data type
XML String
ASCII MEASUREMENT_GEOMETRY String
4.2.3.5 Measurement source

Illumination (e.g. incandescent, daylight, colour temperature, etc.) used during spectral measurement.

This data helps provide a guide to the potential for issues of paper fluorescence, etc.

Format Tag/Keyword Attribute Data type
XML String
ASCII MEASUREMENT_SOURCE String
4.2.3.6 Filter

Identifies the use of physical filter(s) during measurement. This is typically used to denote the use of

filters such as none, D65, Red, Green or Blue.
Format Tag/Keyword Attribute Data type
XML String
ASCII FILTER String
4.2.3.7 Polarization

Identifies the use of a physical polarization filter during measurement. Allowed values are "yes”, “none”

or “na”.
Format Tag/Keyword Attribute Data type
XML String
ASCII POLARIZATION String
© ISO 2022 – All rights reserved
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ISO 28178:2022(E)
4.2.3.8 Weighting function

Indicates such functions as: the CIE standard observer functions used in the calculation of various

data parameters (2 degree and 10 degree); CIE standard illuminant functions used in the calculation of

various data parameters (e.g. D50, D65, etc.); density status response; etc. If used, there shall be at least

one name-value pair following the WEIGHTING_ FUNCTION tag/keyword. The first attribute in the set

shall be "name" and shall identify the particular parameter used. The second shall be "value" and shall

provide the value associated with that name. For ASCII data a string containing the Name and Value

attribute pairs shall follow the weighting function keyword. A semi-colon shall be used to separate

attribute pairs from each other, and within the attribute the name and value shall be separated by a

comma.
Format Tag/Keyword Attribute Data type
XML String
name String
value String
ASCII WEIGHTING_FUNCTION String
4.2.3.9 Computational parameter

Parameter that is used in computing a value from measured data. Name is the name of the calculation,

parameter is the name of the parameter used in the calculation, and value is the value of the parameter.

Format Tag/Keyword Attribute Data type
XML NA
name String
parameter String
value String
ASCII COMPUTATIONAL_PARAMETER String
4.2.3.10 Sample backing

Identifies the backing material used behind the sample during measurement. Allowed values are

“black”, “white”, “self” or “na”.
Format Tag/Keyword Attribute Data type
XML String
ASCII SAMPLE_BACKING String
4.2.3.11 Manufacturer
Indicates the manufacturer of the sample from which the data was measured.
Format Tag/Keyword Attribute Data type
XML String
ASCII MANUFACTURER String
© ISO 2022 – All rights reserved
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ISO 28178:2022(E)
4.2.3.12 Material

Identifies the material or substrate on which the target was produced, using a code identifying the

material.
Format Tag/Keyword Attribute Data type
XML String
ASCII MATERIAL String
4.2.3.13 Target type

Identifies the type of target being measured, e.g. IT8.7/1, IT8.7/3, user-defined, etc.

Format Tag/Keyword Attribute Data type
XML String
ASCII TARGET_TYPE String
4.2.3.14 Colorant(s)
Identifies the colorant(s) used in creating the target.
Format Tag/Keyword Attribute Data type
XML String
ASCII COLORANT String
4.2.3.15 Production date
Identifies year and month of production of the target in the form yyyy:mm.
Format Tag/Keyword Attribute Data type
XML String
year String
month String
ASCII PROD_DATE String
4.2.3.16 Print conditions

Used to define the characteristics of the printed sheet being reported. Where standard conditions have

been defined (e.g. SWOP at nominal) named conditions may suffice. Otherwise, detailed information

shall be provided.
Format Tag/Keyword Attribute Data type
XML String
ASCII PRINT_CONDITIONS String
© ISO 2022 – All rights reserved
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ISO 28178:2022(E)
4.2.3.17 Serial number
Uniquely identifies physical samples.
Format Tag/Keyword Attribute Data type
XML String
ASCII SERIAL String
4.2.3.18 Process colour identification

Uniquely identifies colour and sequence of data columns associated with the numerical values assigned

to each process colour set.
Format Tag/Keyword Attribute Data type
XML
colors_in_set Integer
color_number Integer
color String
ASCII PROCESSCOLOR_ID String

Where the data format identifier PCm_n is used, a process colour tag/keyword (,

PROCESSCOLOR_ID) shall be included for each process colour used. The value m represents the number

of colours in the process colour set. The value n is used to identify the individual colour within the

process colour set and is assigned according to the order of columns in the data block.

4.2.3.19 Spot colour identification

Uniquely identifies colour associated with the numerical value assigned to each spot colour (or line

colour).
Format Tag/Keyword Attribute Data type
XML
nu
...

INTERNATIONAL ISO
STANDARD 28178
Second edition
Graphic technology — Exchange
format for colour and process control
data using XML or ASCII text
Technologie graphique — Format d'échange pour les données de
couleur et de contrôle de procédé en utilisant du texte XML ou ASCII
PROOF/ÉPREUVE
Reference number
ISO 28178:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 28178:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE © ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 28178:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Requirements .......................................................................................................................................................................................................... 2

4.1 General description of a conforming file ......................................................................................................................... 2

4.1.1 XML format .............................................................................................................................................................................. 2

4.1.2 ASCII format ........................................................................................................................................................................... 2

4.2 Tags and keywords ............................................................................................................................................................................. 3

4.2.1 General ........................................................................................................................................................................................ 3

4.2.2 Required preamble tags and keywords ......................................................................................................... 4

4.2.3 Optional tags and keywords .................................................................................................................................... 6

4.2.4 User-defined tags and keywords ...................................................................................................................... 11

4.2.5 Data format identifier .................................................................................................................................................12

4.3 Data tables ............................................................................................................................................................................................... 12

4.3.1 General .....................................................................................................................................................................................12

4.3.2 Table descriptor ...............................................................................................................................................................12

4.3.3 Table name ............................................................................................................................................................................ 12

4.3.4 Data format identifiers............................................................................................................................................... 13

4.3.5 Table data ............................................................................................................................................................................... 16

Annex A (informative) Advantages of an XML data reporting format ..........................................................................17

Annex B (informative) Tag and keyword examples .........................................................................................................................19

Annex C (informative) Sample files ....................................................................................................................................................................24

Annex D (informative) Example of use of user-defined keywords ...................................................................................30

Bibliography .............................................................................................................................................................................................................................37

iii
© ISO 2022 – All rights reserved PROOF/ÉPREUVE
---------------------- Page: 3 ----------------------
ISO 28178:2022(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

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

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 of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/

iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 130, Graphic technology.

This second edition cancels and replaces the first edition (ISO 28178:2009), which has been technically

revised.
The main changes are as follows:

— in 4.2.3.21, an additional tag to remove ambiguity with respect to the printing sequence and the

sequence of tabulating data in particular to ease the data exchange for multi-colour printing has

been added;

— in 4.1.2.1, additional guidance on the use of delimiters, such as point and comma, as well as the

plausibility of the sample ID usage have been provided.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
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ISO 28178:2022(E)
Introduction

This document is intended to support all existing and future graphic arts standards that require the

exchange of measured, computed, or process control data and the associated metadata necessary for its

proper interpretation.

The following requirements were identified when reviewing the needs of such a format:

— applications based on the existing ASCII formats must not be made obsolete;

— data must be in a form that is both human-readable (once the digital file has been displayed using

standard editors, or file readers) and machine-readable;

— data must be readable by automated programs to extract the necessary information;

— data files must be extensible by end users in such a way as to allow additional information to be

included without breaking automated readers of the file;
— data files must be capable of being created by automated programs;
— the format must allow multiple language representation of data.

The file formats chosen to accomplish this task are a combination of XML and extensions of the existing

ASCII keyword-value file format, coupled with the necessary tools to allow appropriate conversions

to and from XML from ASCII keyword-value files. However, either the XML file format or the ASCII

keyword-value file format can be used independently.

These formats make use of predefined XML tags and ASCII keywords. Values are associated with the

tags and keywords and remain in effect until another instance of the tag or keyword. Provision is

made to allow the use of data tables and to separately define the format within data tables. Multiple

occurrences of such data tables within a single file are also permitted. User-defined tags and keywords

are also allowed.

NOTE During the 2021 review process, it was noted that the XML format is not widely used and that its

specification in this document is insufficiently precise to ensure reliable exchange of data.

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INTERNATIONAL STANDARD ISO 28178:2022(E)
Graphic technology — Exchange format for colour and
process control data using XML or ASCII text
1 Scope

This document defines an exchange format for colour and process control data (and the associated

metadata necessary for its proper interpretation) in electronic form using either XML or ASCII

formatted data files. This exchange format maintains human readability of the data as well as enabling

machine readability. It includes a series of predefined tags and keywords, and provides extensibility

through provision for the dynamic definition of additional tags and keywords as necessary. It is focused

primarily on spectral measurement data, colorimetric data, and densitometric data.

This document is intended to be used in conjunction with other standards that will define the required

data, and tags or keywords for specific data exchange applications.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
data format identifier

predefined set of characters, without intervening spaces, forming a unique word that is used to identify

the presence of a defined item of data in a subsequent data table
3.2
keyword

predefined set of characters, without intervening spaces, forming a unique word that is used to identify

the presence of a defined item of information
3.3
schema

XML document that, following the rules established by the World Wide Web Consortium, defines the

structure of a class of xml documents
3.4
value

information immediately following a keyword (3.2) that represents the data content or "value"

associated with that keyword
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ISO 28178:2022(E)
4 Requirements
4.1 General description of a conforming file
4.1.1 XML format
[46]

This file format is an XML format that complies with Extensible Markup Language (XML) 1.0. The

format makes use of predefined tags that identify information commonly used to describe graphic arts

samples. In addition, users of this format are allowed to define tags to tailor the format to their specific

needs according to the rules of XML namespace.
The data file is divided into two sections.

The preamble is the first section. This section provides general information and describes the conditions

under which data was collected. The preamble tag is iso28178.preamble. Tags used in the preamble are

listed in 4.2.

The data section is the second section, which is further divided into two parts. The first part of the data

section provides the information that describes the type and location of the table contents; the second

section contains the data values.

The schema associated with the XML format defined in this document is contained in file iso28178_

data.xsd (available at: https:// standards .iso .org/ iso/ 28178/ ed -2/ en/ ), which is an essential normative

part of this document. This document also provides structural XML tags that are needed for the proper

specification of an XML document instance.

NOTE See Annex A for a discussion on the need and application of the XML data reporting format.

4.1.2 ASCII format
4.1.2.1 General

This file format is an ASCII format keyword-value file. It makes use of predefined keywords and data

tables. Values are associated with the keyword that precedes them and remain in effect until another

instance of the keyword-value pair. Data values are delimited by the BEGIN_DATA and END_DATA

keywords.

Keywords and values, as well as fields within data tables, are separated by white space. Valid white

space characters are space (position 2/0 of ISO/IEC 646), carriage return (position 0/13 of ISO/IEC 646),

newline (position 0/10 of ISO/IEC 646), and tab (position 0/9 of ISO/IEC 646). Keywords may be

separated from values using any valid white space character. Only the space and tab may precede a

keyword on a line. Comments are preceded by a single comment character (a single character keyword).

The comment character is the "#" (position 2/3 of ISO/IEC 646) symbol. Comments may begin any place

on a line, and are terminated by a newline or carriage return character.

NOTE The default separator for exporting data from spreadsheet applications in many regions is a comma

and not a white space character. Conforming files can be created by changing this default to a tab character and

by using the full point character as the decimal separator.
4.1.2.2 Exchanged data file structure

A file containing measurement data would normally be structured as shown in Figure 1. This structure

allows multiple tables of data within a single exchange file.
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ISO 28178:2022(E)
Figure 1 — File structure
4.2 Tags and keywords
4.2.1 General

Most tags and keywords may appear in the file in any order, and may appear multiple times within

the file. Values associated with tags and keywords that appear more than once shall be replaced by

successive instances except for KEYWORD, COMPUTATIONAL_PARAMETER, and WEIGHTING_

FUNCTION. Tags and keywords that describe data tables, however, shall be defined before the data

table. Table 1 lists these tags and keywords. These tags are described in greater detail in this subclause.

Table 1 — XML tags and ASCII keywords that appear in a defined order
Function XML tag ASCII keyword
data table width NUMBER_OF_FIELDS
data format delimiters BEGIN_DATA_FORMAT
END_DATA_FORMAT
data table length NUMBER_OF_SETS
data table delimiters BEGIN_DATA
END_DATA

Data format delimiters shall be preceded by a data table width tag or keyword. Data table delimiters

shall be preceded by a data table length tag or keyword. In the ASCII format, BEGIN_/END_ keywords

begin and end the data format or table data. In the XML format, tags have parameters and/or values and

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ISO 28178:2022(E)

a standard syntax is used; e.g. data format identifiers . Values for tags

and keywords that describe data tables shall be specified for each data table in the file; i.e. inheritance

of these values is not permitted.

ASCII tags and keywords may be composed of any combination of the following: upper case letters;

digits 0 through 9; and ASCII characters $ (position 2/4 of ISO/IEC 646), % (position 2/5 of ISO/IEC 646),

& (position 2/6 of ISO/IEC 646), - (position 2/13 of ISO/IEC 646), / (position 2/15 of ISO/IEC 646), _

(position 5/15 of ISO/IEC 646). By convention all XML tags are lower case.

In the ASCII format, unless used as part of a data format definition, keywords should not be preceded

on a line by other than white space. Unless otherwise noted, each keyword has a character string value

associated with it. All character string values shall be enclosed in quotes, regardless of whether there is

white space contained within the string. Enclosed in quotes means beginning and ending the character

string with the " symbol (position 2/2 of ISO/IEC 646). The " symbol itself is represented within a string

as "" as in the C language syntax.

NOTE The default behaviour of applications writing '.csv' files results in additional quotation marks being

added to files, for example "FILE_DESCRIPTOR ""12642-3 Target definition""", which means that such files do not

conform with this requirement.

For XML tag/keyword entries the form is value. If attribute names are provided

in the XML section of a definition, the information is represented in the XML-formatted data as XML

attribute using the form .

The value associated with keywords NUMBER_OF_FIELDS and NUMBER_OF_SETS shall be an integer.

These values should not be enclosed in quotes.

Format and table delimiters do not have explicit values associated with them but rather enclose either

the data format definition or table data.

The separation between the integer and the fractional part of a given number should be a "full point"

for all entries.

See Annex B for examples of the use of each tag and keyword shown in 4.2.2 and 4.2.3.

4.2.2 Required preamble tags and keywords
4.2.2.1 General

Certain tags and keywords are required as part of each file, while others are optional depending upon

the data to be included. All keywords shall occur before the BEGIN_DATA_FORMAT keyword and the

sequence order for required tags and keywords shall follow the order shown in 4.2.2.2 through 4.2.2.9.

The STANDARD, ORIGINATOR, FILE_DESCRIPTOR and CREATED tags/keywords may occur only once

within a file.

The first line in the ASCII format should be ISO 28178. The use of this identifier indicates that the data

contained in the file adheres to this document. This information is represented in the XML format with

the tag. See 4.2.2.2.

NOTE Strings are widely used including "ECI2002", "CGATS17", "CGATS.17", "ISO 12642-2". These files often

conform to this document with the exception of this identifier.
4.2.2.2 Standard

The use of this identifier indicates that the data contained in the file adheres to the indicated standard.

Format Tag/Keyword Attribute Data type
XML String
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ISO 28178:2022(E)

NOTE There is no ASCII keyword for this because in the ASCII format this information is carried in the first

line of the file.
4.2.2.3 Originator

Identifies the specific system, organization or individual that created the data file.

Format Tag/Keyword Attribute Data type
XML String
ASCII ORIGINATOR String
4.2.2.4 File descriptor
Describes the purpose or contents of the data file.
Format Tag/Keyword Attribute Data type
XML String
ASCII FILE_DESCRIPTOR String
4.2.2.5 Created

Indicates the creation date of the data file. The recommended form for this date is CCYY -MM -DDThh:

mm: ss[Z | +/-hh:mm].
Format Tag/Keyword Attribute Data type
XML String
date String
ASCII CREATED String
4.2.2.6 Number of fields

Number of fields (data format identifiers) that are included in the data format definition that follows.

Format Tag/Keyword Attribute Data type
XML Integer
ASCII NUMBER_OF_FIELDS Integer
4.2.2.7 Data format

Marks the beginning and end of a data format definition. END_DATA_FORMAT shall be preceded by

BEGIN_DATA_FORMAT. See 4.3.4 for information on the data that would be included between these

tags/keywords.
Format Tag/Keyword Attribute Data type
XML NA
ASCII BEGIN_DATA_FORMAT
END_DATA_FORMAT
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ISO 28178:2022(E)
4.2.2.8 Number of sets of data

Number of repetitions or sets of data, i.e. the number of rows in the data table. The associated value is

an integer.
Format Tag/Keyword Attribute Data type
XML Integer
ASCII NUMBER_OF_SETS Integer
4.2.2.9 Data table
Marks the beginning and end of a data table.
Format Tag/Keyword Attribute Data type
XML
NA
ASCII BEGIN_DATA
END_DATA
4.2.3 Optional tags and keywords
4.2.3.1 General

Certain additional general tags and keywords are optional and may be used as needed. The currently

defined optional tags and keywords are defined in 4.2.3.2 to 4.2.3.19. The optional tags and keywords

shall occur after the CREATED tag/keyword and before the NUMBER_OF_FIELDS tag/keyword.

4.2.3.2 Comment

Comments are ignored by automated readers. In the XML syntax, all characters within the

tags are ignored. In the ASCII syntax, all characters between the comment keyword and

the end of line indicator are ignored. End of line is indicated by either carriage return or newline.

Comments indicate to users that the information that follows is of informative interest. Comments need

not be enclosed in quotes. Comments may occur anywhere except within a table.
Format Tag/Keyword Attribute Data type
XML String
ASCII # String
4.2.3.3 Instrumentation

Used to report the specific instrumentation used (e.g. manufacturer, model number and serial number,

etc.) to generate the data reported. This data will often provide more information about the particular

data collected than an extensive list of specific details. This is particularly important for spectral data

or data derived from spectrophotometry.
Format Tag/Keyword Attribute Data type
XML String
manufacturer String
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ISO 28178:2022(E)
model String
serial_number String
ASCII INSTRUMENTATION String
4.2.3.4 Measurement geometry

The type of measurement, either reflection or transmission, should be indicated along with details

of the geometry and the aperture size and shape. For example, for transmission measurements it is

important to identify 0/diffuse, diffuse/0, opal or integrating sphere, etc. For reflection measurements

it is important to identify 0/45, 45/0, sphere (specular included or excluded), etc.

Format Tag/Keyword Attribute Data type
XML String
ASCII MEASUREMENT_GEOMETRY String
4.2.3.5 Measurement source

Illumination (e.g. incandescent, daylight, colour temperature, etc.) used during spectral measurement.

This data helps provide a guide to the potential for issues of paper fluorescence, etc.

Format Tag/Keyword Attribute Data type
XML String
ASCII MEASUREMENT_SOURCE String
4.2.3.6 Filter

Identifies the use of physical filter(s) during measurement. This is typically used to denote the use of

filters such as none, D65, Red, Green or Blue.
Format Tag/Keyword Attribute Data type
XML String
ASCII FILTER String
4.2.3.7 Polarization

Identifies the use of a physical polarization filter during measurement. Allowed values are "yes”, “none”

or “na”.
Format Tag/Keyword Attribute Data type
XML String
ASCII POLARIZATION String
4.2.3.8 Weighting function

Indicates such functions as: the CIE standard observer functions used in the calculation of various

data parameters (2 degree and 10 degree); CIE standard illuminant functions used in the calculation of

various data parameters (e.g. D50, D65, etc.); density status response; etc. If used, there shall be at least

one name-value pair following the WEIGHTING_ FUNCTION tag/keyword. The first attribute in the set

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ISO 28178:2022(E)

shall be "name" and shall identify the particular parameter used. The second shall be "value" and shall

provide the value associated with that name. For ASCII data a string containing the Name and Value

attribute pairs shall follow the weighting function keyword. A semi-colon shall be used to separate

attribute pairs from each other, and within the attribute the name and value shall be separated by a

comma.
Format Tag/Keyword Attribute Data type
XML String
name String
value String
ASCII WEIGHTING_FUNCTION String
4.2.3.9 Computational parameter

Parameter that is used in computing a value from measured data. Name is the name of the calculation,

parameter is the name of the parameter used in the calculation, and value is the value of the parameter.

Format Tag/Keyword Attribute Data type
XML NA
name String
parameter String
value String
ASCII COMPUTATIONAL_PARAMETER String
4.2.3.10 Sample backing

Identifies the backing material used behind the sample during measurement. Allowed values are

“black”, “white”, “self” or “na”.
Format Tag/Keyword Attribute Data type
XML String
ASCII SAMPLE_BACKING String
4.2.3.11 Manufacturer
Indicates the manufacturer of the sample from which the data was measured.
Format Tag/Keyword Attribute Data type
XML String
ASCII MANUFACTURER String
4.2.3.12 Material

Identifies the material or substrate on which the target was produced, using a code identifying the

material.
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ISO 28178:2022(E)
Format Tag/Keyword Attribute Data type
XML String
ASCII MATERIAL String
4.2.3.13 Target type

Identifies the type of target being measured, e.g. IT8.7/1, IT8.7/3, user-defined, etc.

Format Tag/Keyword Attribute Data type
XML String
ASCII TARGET_TYPE String
4.2.3.14 Colorant(s)
Identifies the colorant(s) used in creating the target.
Format Tag/Keyword Attribute Data type
XML String
ASCII COLORANT String
4.2.3.15 Production date
Identifies year and month of production of the target in the form yyyy:mm.
Format Tag/Keyword Attribute Data type
XML String
year String
month String
ASCII PROD_DATE String
4.2.3.16 Print conditions

Used to define the characteristics of the printed sheet being reported. Where standard conditions have

been defined (e.g. SWOP at nominal) named conditions may suffice. Otherwise, detailed information

shall be provided.
Format Tag/Keyword Attribute Data type
XML String
ASCII PRINT_CONDITIONS String
4.2.3.17 Serial number
Uniquely identifies physical samples.
Format Tag/Keyword Attribute Data type
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ISO 28178:2022(E)
XML String
ASCII SERIAL String
4.2.3.18 Process colour identification

Uniquely identifies colour and sequence of data columns associated with the numerical values assigned

to each process colour set.
Format Tag/Keyword Attribute Data type
XML
colors_in_set Integer
color_number Integer
color String
ASCII PROCESSCOLOR_ID String

Where the data format identifier PCm_n is used, a process colour tag/keyword (,

PROCESSCOLOR_ID) shall be included for each process colour used. The value m represents the number

of colours in the process colour set. The value n is used to identify the individual colour within the

process colour set and is assigned according to the order of columns in the data block.

4.2.3.19 Spot colour identificati
...

ISO TC 130 N 4790
Date: 2022-06-2707-14
ISO 28178:2022(E)
ISO TC 130/WG 2
Secretariat: SAC

Graphic technology — Exchange format for colour and process control data using XML or

ASCII text
Élément introductif — Élément central — Élément complémentaire
---------------------- Page: 1 ----------------------

Technologie graphique — Format d'échange pour les données de couleur et de contrôle de

procédé en utilisant du texte XML ou ASCII
---------------------- Page: 2 ----------------------
ISO 28178:2022(E)
© ISO 20XX2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no

part of this publication may be reproduced or utilized otherwise in any form or by any means,

electronic or mechanical, including photocopying, or posting on the internet or an intranet, without

prior written permission. Permission can be requested from either ISO at the address below or

ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.orgwww.iso.org
Published in Switzerland
iv © ISO 2022 – All rights reserved
---------------------- Page: 3 ----------------------
ISO 28178:2022(E)
Contents

Foreword ..................................................................................................................................................................... iv

Introduction ................................................................................................................................................................. v

Annex A (informative) Advantages of an XML data reporting format ...................................................... 19

Annex B (informative) Tag and keyword examples ....................................................................................... 21

Annex C (informative) Sample files ..................................................................................................................... 25

Annex D (informative) Example of use of user-defined keywords ............................................................ 30

Bibliography.............................................................................................................................................................. 36

Foreword ..................................................................................................................................................................... iv

Introduction ............................................................................................................................................................... vi

1 Scope ................................................................................................................................................................ 1

2 Normative references ................................................................................................................................ 1

3 Terms and definitions ................................................................................................................................ 1

4 Requirements ............................................................................................................................................... 2

4.1 General description of a conforming file ............................................................................................. 2

4.1.1 XML format .................................................................................................................................................... 2

4.1.2 ASCII format .................................................................................................................................................. 2

4.2 Tags and keywords ..................................................................................................................................... 4

4.2.1 General ............................................................................................................................................................ 4

4.2.2 Required preamble tags and keywords ............................................................................................... 5

4.2.3 Optional tags and keywords .................................................................................................................... 7

4.2.4 User-defined tags and keywords .......................................................................................................... 11

4.2.5 Data format identifier .............................................................................................................................. 12

4.3 Data tables ................................................................................................................................................... 12

4.3.1 General .......................................................................................................................................................... 12

4.3.2 Table descriptor ........................................................................................................................................ 12

4.3.3 Table name .................................................................................................................................................. 13

4.3.4 Data format identifiers ............................................................................................................................ 13

4.3.5 Table data .................................................................................................................................................... 16

Annex A (informative) Advantages of an XML data reporting format ................................................... 18

Annex B (informative) Tag and keyword examples .................................................................................... 20

Annex C (informative) Sample files .................................................................................................................. 25

Annex D (informative) Example of use of user-defined keywords ......................................................... 33

Bibliography.............................................................................................................................................................. 40

© ISO 2022 – All rights reserved v
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ISO 28178:2022(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

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO

collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

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/directiveswww.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/patentswww.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 of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the World

Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.htmlwww.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 130, Graphic technology.

This second edition cancels and replaces the first edition (ISO 28178:2009), which has been technically

revised.
The main changes are as follows:

— in 4.2.3.21, an additional tag to remove ambiguity with respect to the printing sequence and the

sequence of tabulating data in particular to ease the data exchange for multi-colour printing washas

been added;

— in 4.1.2.1, additional guidance on the use of delimiters, such as point and comma, as well as the

plausibility of the sample ID usage washave been provided.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at
www.iso.org/members.htmlwww.iso.org/members.html.
vi © ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
ISO 28178:2022(E)
Introduction

This document is intended to support all existing and future graphic arts standards that require the

exchange of measured, computed, or process control data and the associated metadata necessary for its

proper interpretation.

The following requirements were identified when reviewing the needs of such a format:

— applications based on the existing ASCII formats shallmust not be made obsolete;

— data shallmust be in a form that is both human-readable (once the digital file has been displayed

using standard editors, or file readers) and machine-readable;

— data shallmust be readable by automated programs to extract the necessary information;

— data files shallmust be extensible by end users in such a way as to allow additional information to be

included without breaking automated readers of the file;
— data files shallmust be capable of being created by automated programs;
— the format shallmust allow multiple language representation of data.

The file formats chosen to accomplish this task are a combination of XML and extensions of the existing

ASCII keyword-value file format, coupled with the necessary tools to allow appropriate conversions to

and from XML from ASCII keyword-value files. However, either the XML file format or the ASCII

keyword-value file format can be used independently.

These formats make use of predefined XML tags and ASCII keywords. Values are associated with the tags

and keywords and remain in effect until another instance of the tag or keyword. Provision is made to

allow the use of data tables and to separately define the format within data tables. Multiple occurrences

of such data tables within a single file are also permitted. User-defined tags and keywords are also

allowed.

NOTE During the 2021 review process, it was noted that the XML format is not widely used and that its

specification in this document is insufficiently precise to ensure reliable exchange of data.

© ISO 2022 – All rights reserved vii
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Error! Reference source not found. ISO 28178:2022(E)
Graphic technology — Exchange format for colour and process
control data using XML or ASCII text
1 Scope

This document defines an exchange format for colour and process control data (and the associated

metadata necessary for its proper interpretation) in electronic form using either XML or ASCII formatted

data files. This exchange format maintains human readability of the data as well as enabling machine

readability. It includes a series of predefined tags and keywords, and provides extensibility through

provision for the dynamic definition of additional tags and keywords as necessary. It is focused primarily

on spectral measurement data, colorimetric data, and densitometric data.

This document is intended to be used in conjunction with other standards that will define the required

data, and tags or keywords for specific data exchange applications.

NOTE During the 2021 review process, it was noted that the XML format is not widely used and that its

specification in this document is insufficiently precise to ensure reliable exchange of data.

32 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

There are no normative references in this document.
43 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp

— IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/

3.1
data format identifier

predefined set of characters, without intervening spaces, forming a unique word that is used to identify

the presence of a defined item of data in a subsequent data table
3.2
keyword

predefined set of characters, without intervening spaces, forming a unique word that is used to identify

the presence of a defined item of information
© ISO 2022 – All rights reserved 1
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ISO 28178:2022(E)
3.3
schema

XML document that, following the rules established by the World Wide Web Consortium, defines the

structure of a class of xml documents
3.4
value

information immediately following a keyword (3.2) that represents the data content or "value" associated

with that keyword
54 Requirements
5.14.1 General description of a conforming file
5.1.14.1.1 XML format
[4] [46]

This file format is an XML format that complies with Extensible Markup Language (XML) 1.0 .. The

format makes use of predefined tags that identify information commonly used to describe graphic arts

samples. In addition, users of this format are allowed to define tags to tailor the format to their specific

needs according to the rules of XML namespace.
The data file is divided into two sections.

The preamble is the first section. This section provides general information and describes the conditions

under which data was collected. The preamble tag is iso28178.preamble. Tags used in the preamble are

listed in 4.2.

The data section is the second section, which is further divided into two parts. The first part of the data

section provides the information that describes the type and location of the table contents; the second

section contains the data values.

The schema associated with the XML format defined in this document is contained in file

iso28178_data.xsd, (available at: https://standards.iso.org/iso/28178/ed-2/en/), which is an essential

normative part of this document. This document also provides structural XML tags that are needed for

the proper specification of an XML document instance.

NOTE See Annex A for a discussion on the need and application of the XML data reporting format.

5.1.24.1.2 ASCII format
5.1.2.14.1.2.1 General

This file format is an ASCII format keyword-value file. It makes use of predefined keywords and data

tables. Values are associated with the keyword that precedes them and remain in effect until another

instance of the keyword-value pair. Data values are delimited by the BEGIN_DATA and END_DATA

keywords.

Keywords and values, as well as fields within data tables, are separated by white space. Valid white space

[3]

characters are space (position 2/0 of ISO/IEC 646 ),), carriage return (position 0/13 of ISO/IEC 646),

newline (position 0/10 of ISO/IEC 646), and tab (position 0/9 of ISO/IEC 646). Keywords may be

separated from values using any valid white space character. Only the space and tab may precede a

keyword on a line. Comments are preceded by a single comment character (a single character keyword).

The comment character is the "#" (position 2/3 of ISO/IEC 646) symbol. Comments may begin any place

on a line, and are terminated by a newline or carriage return character.
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ISO 28178:2022(E)

NOTE The default separator for exporting data from spreadsheet applications in many regions is a comma and

not a white space character. Conforming files can be created by changing this default to a tab character and by using

the full point character as the decimal separator.
5.1.2.24.1.2.2 Exchanged data file structure

A file containing measurement data would normally be structured as shown in Figure 1. This structure

allows multiple tables of data within a single exchange file.
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ISO 28178:2022(E)
Figure 1 — File structure
5.24.2 Tags and keywords
5.2.14.2.1 General

Most tags and keywords may appear in the file in any order, and may appear multiple times within the

file. Values associated with tags and keywords that appear more than once shall be replaced by successive

instances except for KEYWORD, COMPUTATIONAL_PARAMETER, and WEIGHTING_FUNCTION. Tags and

keywords that describe data tables, however, shall be defined before the data table. Table 1 lists these

tags and keywords. These tags are described in greater detail belowin this subclause.

Table 1 — XML tags and ASCII keywords that appear in a defined order
Function XML tag ASCII keyword
data table width NUMBER_OF_FIELDS
data format delimiters BEGIN_DATA_FORMAT
END_DATA_FORMAT
data table length NUMBER_OF_SETS
data table delimiters BEGIN_DATA
END_DATA
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ISO 28178:2022(E)

Data format delimiters shall be preceded by a data table width tag or keyword. Data table delimiters shall

be preceded by a data table length tag or keyword. In the ASCII format, BEGIN_/END_ keywords begin

and end the data format or table data. In the XML format, tags have parameters and/or values and a

standard syntax is used; e.g. data format identifiers . Values for tags and

keywords that describe data tables shall be specified for each data table in the file; i.e. inheritance of these

values is not permitted.

ASCII tags and keywords may be composed of any combination of the following: upper case letters; digits

0 through 9; and ASCII characters $ (position 2/4 of ISO/IEC 646), % (position 2/5 of ISO/IEC 646), &

(position 2/6 of ISO/IEC 646), - (position 2/13 of ISO/IEC 646), / (position 2/15 of ISO/IEC 646), _

(position 5/15 of ISO/IEC 646). By convention all XML tags are lower case.

In the ASCII format, unless used as part of a data format definition, keywords should not be preceded on

a line by other than white space. Unless otherwise noted, each keyword has a character string value

associated with it. All character string values shall be enclosed in quotes, regardless of whether there is

white space contained within the string. Enclosed in quotes means beginning and ending the character

string with the " symbol (position 2/2 of ISO/IEC 646). The " symbol itself is represented within a string

as "" as in the C language syntax.

NOTE The default behaviour of applications writing '.csv' files results in additional quotation marks being added

to files, for example "FILE_DESCRIPTOR ""12642-3 Target definition""", which means that such files do not conform

with this requirement.

For XML tag/keyword entries the form is value. If attribute names are provided in

the XML section of a definition, the information is represented in the XML-formatted data as XML

attribute using the form .

The value associated with keywords NUMBER_OF_FIELDS and NUMBER_OF_SETS shall be an integer.

These values should not be enclosed in quotes.

Format and table delimiters do not have explicit values associated with them but rather enclose either

the data format definition or table data.

The separation between the integer and the fractional part of a given number should be a "full point" for

all entries.

See Annex B for examples of the use of each tag and keyword shown in 4.2.2 and 4.2.3.

5.2.24.2.2 Required preamble tags and keywords
5.2.2.14.2.2.1 General

Certain tags and keywords are required as part of each file, while others are optional depending upon the

data to be included. All keywords shall occur before the BEGIN_DATA_FORMAT keyword and the

sequence order for required tags and keywords shall follow the order shown in 4.2.2.2 through 4.2.2.9.

The STANDARD, ORIGINATOR, FILE_DESCRIPTOR and CREATED tags/keywords may occur only once

within a file.

The first line in the ASCII format should be ISO 28178. The use of this identifier indicates that the data

contained in the file adheres to this document. This information is represented in the XML format with

the tag. See 4.2.2.2.

NOTE Strings are widely used including "ECI2002", "CGATS17", "CGATS.17", "ISO 12642-2". These files often

conform to this document with the exception of this identifier.
5.2.2.24.2.2.2 Standard

The use of this identifier indicates that the data contained in the file adheres to the indicated standard.

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ISO 28178:2022(E)
Format Tag/Keyword Attribute Data type
XML String

NOTE There is no ASCII keyword for this because in the ASCII format this information is carried in the first line

of the file.
5.2.2.34.2.2.3 Originator

Identifies the specific system, organization or individual that created the data file.

Format Tag/Keyword Attribute Data type
XML String
ASCII ORIGINATOR String
5.2.2.44.2.2.4 File descriptor
Describes the purpose or contents of the data file.
Format Tag/Keyword Attribute Data type
XML String
ASCII FILE_DESCRIPTOR String
5.2.2.54.2.2.5 Created

Indicates the creation date of the data file. The recommended form for this date is CCYY-MM-

DDThh:mm:ss[Z | +/-hh:mm].
Format Tag/Keyword Attribute Data type
XML String
date String
ASCII CREATED String
5.2.2.64.2.2.6 Number of fields

Number of fields (data format identifiers) that are included in the data format definition that follows.

Format Tag/Keyword Attribute Data type
XML Integer
ASCII NUMBER_OF_FIELDS Integer
5.2.2.74.2.2.7 Data format

Marks the beginning and end of a data format definition. END_DATA_FORMAT shall be preceded by

BEGIN_DATA_FORMAT. See 4.3.4 for information on the data that would be included between these

tags/keywords.
Format Tag/Keyword Attribute Data type
XML NA
ASCII BEGIN_DATA_FORMAT
END_DATA_FORMAT
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ISO 28178:2022(E)
5.2.2.84.2.2.8 Number of sets of data

Number of repetitions or sets of data, i.e. the number of rows in the data table. The associated value is an

integer.
Format Tag/Keyword Attribute Data type
XML Integer
ASCII NUMBER_OF_SETS Integer
5.2.2.94.2.2.9 Data table
Marks the beginning and end of a data table.
Format Tag/Keyword Attribute Data type
XML
NA
ASCII BEGIN_DATA
END_DATA
5.2.34.2.3 Optional tags and keywords
5.2.3.14.2.3.1 General

Certain additional general tags and keywords are optional and may be used as needed. The currently

defined optional tags and keywords are defined in 4.2.3.2 to 4.2.3.19. The optional tags and keywords

shall occur after the CREATED tag/keyword and before the NUMBER_OF_FIELDS tag/keyword.

5.2.3.24.2.3.2 Comment

Comments are ignored by automated readers. In the XML syntax, all characters within the

tags are ignored. In the ASCII syntax, all characters between the comment keyword and the

end of line indicator are ignored. End of line is indicated by either carriage return or newline. Comments

indicate to users that the information that follows is of informative interest. Comments need not be

enclosed in quotes. Comments may occur anywhere except within a table.
Format Tag/Keyword Attribute Data type
XML String
ASCII # String
5.2.3.34.2.3.3 Instrumentation

Used to report the specific instrumentation used (e.g. manufacturer, model number and serial number,

etc.) to generate the data reported. This data will often provide more information about the particular

data collected than an extensive list of specific details. This is particularly important for spectral data or

data derived from spectrophotometry.
Format Tag/Keyword Attribute Data type
XML String
manufacturer String
model String
serial_number String
ASCII INSTRUMENTATION String
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ISO 28178:2022(E)
5.2.3.44.2.3.4 Measurement geometry

The type of measurement, either reflection or transmission, should be indicated along with details of the

geometry and the aperture size and shape. For example, for transmission measurements it is important

to identify 0/diffuse, diffuse/0, opal or integrating sphere, etc. For reflection measurements it is

important to identify 0/45, 45/0, sphere (specular included or excluded), etc.
Format Tag/Keyword Attribute Data type
XML String
ASCII MEASUREMENT_GEOMETRY String
5.2.3.54.2.3.5 Measurement source

Illumination (e.g. incandescent, daylight, colour temperature, etc.) used during spectral measurement.

This data helps provide a guide to the potential for issues of paper fluorescence, etc.

Format Tag/Keyword Attribute Data type
XML String
ASCII MEASUREMENT_SOURCE String
5.2.3.64.2.3.6 Filter

Identifies the use of physical filter(s) during measurement. This is typically used to denote the use of

filters such as none, D65, Red, Green or Blue.
Format Tag/Keyword Attribute Data type
XML String
ASCII FILTER String
5.2.3.74.2.3.7 Polarization

Identifies the use of a physical polarization filter during measurement. Allowed values are "yes”, “none”

or “na”.
Format Tag/Keyword Attribute Data type
XML String
ASCII POLARIZATION String
5.2.3.84.2.3.8 Weighting function

Indicates such functions as: the CIE standard observer functions used in the calculation of various data

parameters (2 degree and 10 degree); CIE standard illuminant functions used in the calculation of various

data parameters (e.g. D50, D65, etc.); density status response; etc. If used, there shall be at least one name-

value pair following the WEIGHTING_ FUNCTION tag/keyword. The first attribute in the set shall be

"name" and shall identify the particular parameter used. The second shall be "value" and shall provide

the value associated with that name. For ASCII data a string containing the Name and Value attribute pairs

shall follow the weighting function keyword. A semi-colon shall be used to separate attribute pairs from

each other, and within the attribute the name and value shall be separated by a comma.

Format Tag/Keyword Attribute Data type
XML String
name String
value String
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ISO 28178:2022(E)
ASCII WEIGHTING_FUNCTION String
5.2.3.94.2.3.9 Computational parameter

Parameter that is used in computing a value from measured data. Name is the name of the calculation,

parameter is the name of the parameter used in the calculation, and value is the value of the parameter.

Format Tag/Keyword Attribute Data type
XML NA
name String
parameter String
value String
ASCII COMPUTATIONAL_PARAMETER String
5.2.3.104.2.3.10 Sample backing

Identifies the backing material used behind the sample during measurement. Allowed values are “black”,

“white”, “self” or “na”.
Format Tag/Keyword Attribute Data type
XML String
ASCII SAMPLE_BACKING String
5.2.3.114.2.3.11 Manufacturer
Indicates the manufacturer of the sample from which the data was measured.
Format Tag/Keyword Attribute Data type
XML String
ASCII MANUFACTURER String
5.2.3.124.2.3.12 Material

Identifies the material or substrate on which the target was produced, using a code identifying the

material.
Format Tag/Keyword Attribute Data type
XML String
ASCII MATERIAL String
5.2.3.134.2.3.13 Target type

Identifies the type of target being measured, e.g. IT8.7/1, IT8.7/3, user-defined, etc.

Format Tag/Keyword Attribute Data type
XML String
ASCII TARGET_TYPE String
5.2.3.144.2.3.14 Colorant(s)
Identifies the colorant(s) used in creating the target.
Format Tag/Keyword Attribute Data type
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ISO 28178:2022(E)
XML String
ASCII COLORANT String
5.2.3.154.2.3.15 Production date
Identifi
...

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