Graphic technology - Methods of adjustment of the colour reproduction of a printing system to match a set of characterization data

This Technical Specification specifies three methods for the adjustment of the digital content data that is input to a printing system to achieve consistency in the printed results among a number of presses printing to the same general aim conditions. These three methods are generally identified as a) the matching of tone value curves, b) the use of near-neutral scales, and c) the use of CMYK to CMYK multi-dimensional transforms. The procedures for establishing the aim condition for the necessary transfer curves, the procedures for determining the individual transfer curves, and a comparison of the applicability of these three methods are included. These adjustment procedures are applicable to printing systems that use CMYK colourants but are not restricted to those that use traditional ink on paper printing but can involve other marking technologies such as those used for proofing and/or digital printing.

Technologie graphique - Méthodes d'ajustage de la reproduction de couleurs d'un système d'impression pour correspondre à un ensemble de données de caractérisation

Grafična tehnologija - Metode za prilagajanje barvne reprodukcije na tiskarskem sistemu, da ustreza želenim karakterističnim vrednostim

Ta tehnična specifikacija določa tri metode za prilagajanje digitalnih vsebinskih podatkov, ki se vnašajo v tiskarski sistem, za doseganje doslednosti natisnjenih rezultatov med številnimi tiskarskimi stroji, ki tiskajo pod istimi splošnimi ciljnimi pogoji. Te tri metode se v splošnem označujejo kot a) prilagajanje krivulj vrednosti tona, b) uporaba skoraj nevtralnih lestvic, in c) uporaba večdimenzionalnih transformacij iz CMYK v CMYK. Vključeni so postopki za vzpostavljanje ciljnih pogojev za potrebne krivulje prenosa, postopki za določanje posameznih krivulj prenosa in primerjava uporabnosti teh treh metod. Postopki prilagajanja veljajo za tiskarske sisteme, ki uporabljajo barvila CMYK, a niso omejeni na sisteme, ki uporabljajo tradicionalno tiskanje barve na papir, pač pa lahko vključujejo druge označevalne tehnologije, kot so tiste, ki se uporabljajo za poskusno in/ali digitalno tiskanje.

General Information

Status
Published
Publication Date
08-Apr-2010
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
12-Mar-2010
Due Date
17-May-2010
Completion Date
09-Apr-2010

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TECHNICAL ISO/TS
SPECIFICATION 10128
First edition
2009-07-01
Graphic technology — Methods of
adjustment of the colour reproduction of
a printing system to match a set of
characterization data
Technologie graphique — Méthodes d'ajustage de la reproduction de
couleurs d'un système d'impression pour correspondre à un ensemble
de données de caractérisation
Reference number
ISO/TS 10128:2009(E)
ISO 2009
---------------------- Page: 1 ----------------------
ISO/TS 10128:2009(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

COPYRIGHT PROTECTED DOCUMENT
© ISO 2009

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2009 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TS 10128:2009(E)
Contents Page

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

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

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

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

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

4 Procedures .............................................................................................................................................3

4.1 General....................................................................................................................................................3

4.2 Matching of tone value curves .............................................................................................................4

4.3 Use of near-neutral scales ....................................................................................................................5

4.4 Use of CMYK to CMYK multi-dimensional transforms ......................................................................7

5 Applicability of each method................................................................................................................8

Annex A (normative) Tone value .......................................................................................................................9

Bibliography ......................................................................................................................................................12

© ISO 2009 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/TS 10128:2009(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

In other circumstances, particularly when there is an urgent market requirement for such documents, a

technical committee may decide to publish other types of normative document:

⎯ an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in

an ISO working group and is accepted for publication if it is approved by more than 50 % of the members

of the parent committee casting a vote;

⎯ an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical

committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting

a vote.

An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a

further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is

confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an

International Standard or be withdrawn.
ISO/TS 10128 was prepared by Technical Committee ISO/TC 130, Graphic technology.
iv © ISO 2009 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TS 10128:2009(E)
Introduction

As the printing and publishing world has embraced the use of digital data and the preparation of printing plates

directly from digital data (often referred to as computer to plate or CTP), it has struggled to find ways to take

better advantage of the electronic data manipulation opportunities offered. When traditional half-tone film was

the medium of exchange of final material and the input to the printing plate and press operation, the primary

methodology available to the printer to match industry aims and standards was to force the press, ink and

paper to be as close as possible to the references upon which the printing standards were based. Today, with

digital data input, it is recognized that modification of that digital data can be used to compensate (adjust) for

some of the differences in press, ink and paper between various printing sites and between the actual

conditions at a specific site and the reference or standard printing condition.

As part of the introduction of digital technology, the printing industries (and its standards activities) have begun

to establish reference characterization data corresponding to various printing specifications and conditions.

Characterization data is generally defined as the relationship between the CMYK digital input values (in the

data file exchanged) and the measured colorimetric values for the colour printed in response to these values.

Discussions within Technical Committee ISO/TC 130 have identified three general methods by which

compensation for differences in printing conditions can be accomplished. Two of these make use of individual

one-dimensional transforms (i.e. plate curves) for each printing channel, but differ in the method by which

these transforms are determined. These are referred to as matching of tone value curves and use of near-

neutral scales. The third method makes use of multi-dimensional transforms such as International Color

Consortium (ICC) device-link profiles.

The features and general methodology for use of these adjustment techniques is the subject of this Technical

Specification. The goal is to provide a common understanding of these procedures across the industry, to

allow consistency between implementations, and to facilitate communication of the adjustments used/desired

in particular workflows.

It is important to recognize that these are not competitive solutions, but each have different strengths and

weaknesses in individual workflow applications. It is the choice of the individual print facility and/or the

involved trade associations to decide how to best apply these capabilities, made possible through the use of

digital data.

The basic assumption behind the use of characterization data and these correction techniques is that a

printing process can be repeatedly restored to a prior printing condition and that condition can be maintained

both within a run and between runs. A variety of process control methods can be used to achieve this

repeatability. Solid ink reflectance density and tone value increase based on the specific materials involved,

and tied back to the conditions established during characterization are common process control tools that are

used in addition to the data adjustment techniques described in this document. These adjustment techniques

work together with process control to achieve the printing quality desired.

The International Organization for Standardization (ISO) draws attention to the fact that it is claimed that

compliance with this document may involve the use of a patent concerning recalibrating a multi-colour imaging

system given in 4.3.

ISO takes no position concerning the evidence, validity and scope of this patent right.

The holder of this patent right has assured ISO that he/she is willing to negotiate licences free of charge with

applicants throughout the world. In this respect, the statement of the holder of this patent right is registered

with ISO. Information may be obtained from:
Intellectual Property Standards and Transactions
Eastman Kodak Company
343 State Street, Rochester, NY 14650, USA
© ISO 2009 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO/TS 10128:2009(E)

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights other than those identified above. ISO shall not be held responsible for identifying any or all such patent

rights.
vi © ISO 2009 – All rights reserved
---------------------- Page: 6 ----------------------
TECHNICAL SPECIFICATION ISO/TS 10128:2009(E)
Graphic technology — Methods of adjustment of the colour
reproduction of a printing system to match a set of
characterization data
1 Scope

This Technical Specification specifies three methods for the adjustment of the digital content data that is input

to a printing system to achieve consistency in the printed results among a number of presses printing to the

same general aim conditions. These three methods are generally identified as
a) the matching of tone value curves,
b) the use of near-neutral scales, and
c) the use of CMYK to CMYK multi-dimensional transforms.

The procedures for establishing the aim condition for the necessary transfer curves, the procedures for

determining the individual transfer curves, and a comparison of the applicability of these three methods are

included.

These adjustment procedures are applicable to printing systems that use CMYK colourants but are not

restricted to those that use traditional ink on paper printing but can involve other marking technologies such as

those used for proofing and/or digital printing.
2 Normative references

The following referenced documents are indispensable for the application 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.

ISO 12642-1, Graphic technology — Input data for characterization of 4-colour process printing — Part 1:

Initial data set

ISO 12642-2, Graphic technology — Input data for characterization of 4-colour process printing — Part 2:

Expanded data set

ISO 13655, Graphic technology — Spectral measurement and colorimetric computation for graphic arts

images

ISO 15076-1, Image technology colour management — Architecture, profile format and data structure —

Part 1: Based on ICC.1:2004-10
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
© ISO 2009 – All rights reserved 1
---------------------- Page: 7 ----------------------
ISO/TS 10128:2009(E)
3.1
adjustment of a printing system with digital data

systematic modification of the content data received, to enable the results printed on a specific device to

match the appearance of the same content data as would have been printed on a reference device

3.2
digital printing

printing directly from digital data when there is no intermediate image carrier, or when the image carrier is

refreshed for each impression, and thus each impression can be different in content if desired

3.3
grey balance

set of tone values for cyan, magenta and yellow that are expected to appear as an achromatic grey under

specified viewing conditions when printed using the specified printing conditions

NOTE 1 Adapted from ISO 12647-1.

NOTE 2 The user can choose between the following two practical definitions and one theoretical definition of grey,

depending upon the particular context:
a) practical definitions:
1) a colour having the same CIELAB a* and b* values as the print substrate;

2) a colour that has the same CIELAB a* and b* values as a half-tone tint of similar L* value printed with black ink;

b) theoretical definition: the colorimetric definition of grey is when the CIELAB a* and b* values both equal 0.

3.4
tone value

proportional printing value encoded in a data file and interpreted as defined in the file format specification

NOTE 1 Most files store these data as 8-bit integer values, i.e. 0 to 255. The tone value, A, expressed as a percentage

of a pixel, is typically computed from the equation
⎛⎞VV−
A=×100
VV−
⎝⎠100 0
where
V is the integer value of the pixel in the file;
V is the integer value corresponding to a tone value of 0 %;
V is the integer value corresponding to a tone value of 100 %.
100
NOTE 2 Adapted from ISO 12647-1.
3.5
tone value increase

difference between the tone value in the digital data file and the tone value on the printed sheet

NOTE Adapted from ISO 12647-1.
2 © ISO 2009 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/TS 10128:2009(E)
4 Procedures
4.1 General
4.1.1 Overview

Printing standards, in general, specify the ink and paper to be used and the process control parameters in

colorimetric terms. When the inks are well characterized, densitometric aims may also be included for

reference. The ISO 2846 series of International Standards provides the mechanism to specify the colour and

transparency of the ink. Specification of paper is not well defined and is generally limited to an identification of

colour, translucency or grammage, and a reference to industry grades or classifications.

The outer gamut of the printable colour volume is primarily defined by the combination of the colour of the

paper, the colour of solids of the primary inks and of the overprinted solids of two primary inks, and the colour

of the overprinted solids of three primary inks in combination with the black ink. These are included in the

printing conditions defined in the ISO 12647 series of International Standards and are also typically included in

other printing specifications along with reference aims for densitometric data and tone value increase.

Characterization data associated with such printing standards is usually prepared from print test data or data

from earlier tests. In either case, it is typically modified and smoothed so as to match the specified values for

the aim parameters and to represent smooth transitions within the colour volume.

In some situations, a printing system can be adjusted to match a reference by adjusting tone value increase to

match the reference. The principal assumptions are

a) if the primary and secondary colour solids are correct, the outer printing gamut is correct,

b) if the tone curves for the individual single colour scales match those of the reference printing condition,

then the internal overprint data will also match the reference, and

c) within limits, differences in the tone value increase between presses (or between a press and the

reference printing condition) can be compensated for by a series of single channel changes in the input

tone values.

It is, of course, assumed that the paper and ink comply with the specifications for the printing standard being

matched within reasonable tolerances.

The first two methods described in this Technical Specification use such single channel changes and differ

only in the procedure used to determine the individual channel corrections.

The third method assumes that there is sufficient interaction between channels that a series of single channel

corrections are not sufficient. It makes use of an ICC device-link transform (or other mechanism which maps

the device-dependent printing data of one system into the device-dependent printing data of another system)

which essentially is a predefined four-dimensional transform. The reason that an ICC device-link is used

instead of classic ICC colour management is that the transforms included in a device-link profile can be tuned

to preserve the black channel (single colour black stays as a single colour). Classic ICC colour management

converts the CMYK data back into profile connection space (PCS) data and then re-computes the individual

colour separations to create a new set of CMYK data.

All three methods depend on the use of the specified paper and ink, and on achieving the correct colorimetric

values of the process colour solids and two-colour overprint solids.

Although the descriptions that follow refer to the “press to be used for actual printing”, it is recognized that

often process control within an organization is sufficiently managed or that presses belonging to a single

“family” (e.g. same brand or similar models) are sufficiently similar that the same set of corrections can be

applied in a broader sense than simply to a single press. Furthermore, although the term press is used

throughout this document to refer to the intended printing device, these procedures may be used with proofing

devices or with digital printing devices operated in traditional half-tone, continuous tone, or non-traditional

imaging modes.
© ISO 2009 – All rights reserved 3
---------------------- Page: 9 ----------------------
ISO/TS 10128:2009(E)
4.1.2 Printing specifications

Whenever possible, printing standards should use the printing conditions defined in the applicable part of

ISO 12647, or should be based on these conditions.
4.1.3 Ink specifications

The various parts of ISO 12647 specify use of inks based on the appropriate part of ISO 2846. However, even

when the printing specifications used are not based on ISO 12647, the ink specified should be based on the

appropriate part of ISO 2846 or use similar testing procedures for its definition.

4.1.4 Characterization data

All characterization data should be based on the ink value data sets defined in either ISO 12642-1 or

ISO 12642-2. Measurement of printed samples of these ink value data sets shall be accomplished in

accordance with ISO 13655. Colour management profiles based on such characterization data shall be

created in accordance with ISO 15076-1.
4.1.5 Determination of tone value

Tone value is traditionally calculated from reflectance density data and is an estimate of the percentage of the

surface which appears to be covered by a uniform layer of a colorant of a single colour (if light scattering in the

substrate and other optical phenomena are ignored). The choice of which reflectance density filter set to use

(reflectance density status as defined in ISO 5) is generally not an issue as long as both the reference

characterization data and the press evaluation data are based on the same reflectance density status (as

defined in ISO 5).

Use of a spectrophotometer, adjusted so that its spectral pass band is centred on the wavelength region

where the print exhibits its maximum light absorbance, provides the best estimate of apparent tone value.

However, for process control of a running press, status (see ISO 5) reflectance density data is usually more

available and, for that reason, the tone value (and thus tone value increase) “aim” (i.e. value to aim for) is

usually based on densitometric data. However, when colorimetric data is available, tone value based on

colorimetric data may be used for both the characterization data reference and the press evaluation data.

Annex A provides additional information about, and computational techni
...

SLOVENSKI STANDARD
SIST-TS ISO/TS 10128:2010
01-maj-2010
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VLVWHPXGDXVWUH]DåHOHQLPNDUDNWHULVWLþQLPYUHGQRVWLP

Graphic technology - Methods of adjustment of the colour reproduction of a printing

system to match a set of characterization data
Technologie graphique - Méthodes d'ajustage de la reproduction de couleurs d'un

système d'impression pour correspondre à un ensemble de données de caractérisation

Ta slovenski standard je istoveten z: ISO/TS 10128:2009
ICS:
37.100.10 Reprodukcijska oprema Reproduction equipment
SIST-TS ISO/TS 10128:2010 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST-TS ISO/TS 10128:2010
---------------------- Page: 2 ----------------------
SIST-TS ISO/TS 10128:2010
TECHNICAL ISO/TS
SPECIFICATION 10128
First edition
2009-07-01
Graphic technology — Methods of
adjustment of the colour reproduction of
a printing system to match a set of
characterization data
Technologie graphique — Méthodes d'ajustage de la reproduction de
couleurs d'un système d'impression pour correspondre à un ensemble
de données de caractérisation
Reference number
ISO/TS 10128:2009(E)
ISO 2009
---------------------- Page: 3 ----------------------
SIST-TS ISO/TS 10128:2010
ISO/TS 10128:2009(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

COPYRIGHT PROTECTED DOCUMENT
© ISO 2009

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2009 – All rights reserved
---------------------- Page: 4 ----------------------
SIST-TS ISO/TS 10128:2010
ISO/TS 10128:2009(E)
Contents Page

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

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

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

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

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

4 Procedures .............................................................................................................................................3

4.1 General....................................................................................................................................................3

4.2 Matching of tone value curves .............................................................................................................4

4.3 Use of near-neutral scales ....................................................................................................................5

4.4 Use of CMYK to CMYK multi-dimensional transforms ......................................................................7

5 Applicability of each method................................................................................................................8

Annex A (normative) Tone value .......................................................................................................................9

Bibliography ......................................................................................................................................................12

© ISO 2009 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST-TS ISO/TS 10128:2010
ISO/TS 10128:2009(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

In other circumstances, particularly when there is an urgent market requirement for such documents, a

technical committee may decide to publish other types of normative document:

⎯ an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in

an ISO working group and is accepted for publication if it is approved by more than 50 % of the members

of the parent committee casting a vote;

⎯ an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical

committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting

a vote.

An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a

further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is

confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an

International Standard or be withdrawn.
ISO/TS 10128 was prepared by Technical Committee ISO/TC 130, Graphic technology.
iv © ISO 2009 – All rights reserved
---------------------- Page: 6 ----------------------
SIST-TS ISO/TS 10128:2010
ISO/TS 10128:2009(E)
Introduction

As the printing and publishing world has embraced the use of digital data and the preparation of printing plates

directly from digital data (often referred to as computer to plate or CTP), it has struggled to find ways to take

better advantage of the electronic data manipulation opportunities offered. When traditional half-tone film was

the medium of exchange of final material and the input to the printing plate and press operation, the primary

methodology available to the printer to match industry aims and standards was to force the press, ink and

paper to be as close as possible to the references upon which the printing standards were based. Today, with

digital data input, it is recognized that modification of that digital data can be used to compensate (adjust) for

some of the differences in press, ink and paper between various printing sites and between the actual

conditions at a specific site and the reference or standard printing condition.

As part of the introduction of digital technology, the printing industries (and its standards activities) have begun

to establish reference characterization data corresponding to various printing specifications and conditions.

Characterization data is generally defined as the relationship between the CMYK digital input values (in the

data file exchanged) and the measured colorimetric values for the colour printed in response to these values.

Discussions within Technical Committee ISO/TC 130 have identified three general methods by which

compensation for differences in printing conditions can be accomplished. Two of these make use of individual

one-dimensional transforms (i.e. plate curves) for each printing channel, but differ in the method by which

these transforms are determined. These are referred to as matching of tone value curves and use of near-

neutral scales. The third method makes use of multi-dimensional transforms such as International Color

Consortium (ICC) device-link profiles.

The features and general methodology for use of these adjustment techniques is the subject of this Technical

Specification. The goal is to provide a common understanding of these procedures across the industry, to

allow consistency between implementations, and to facilitate communication of the adjustments used/desired

in particular workflows.

It is important to recognize that these are not competitive solutions, but each have different strengths and

weaknesses in individual workflow applications. It is the choice of the individual print facility and/or the

involved trade associations to decide how to best apply these capabilities, made possible through the use of

digital data.

The basic assumption behind the use of characterization data and these correction techniques is that a

printing process can be repeatedly restored to a prior printing condition and that condition can be maintained

both within a run and between runs. A variety of process control methods can be used to achieve this

repeatability. Solid ink reflectance density and tone value increase based on the specific materials involved,

and tied back to the conditions established during characterization are common process control tools that are

used in addition to the data adjustment techniques described in this document. These adjustment techniques

work together with process control to achieve the printing quality desired.

The International Organization for Standardization (ISO) draws attention to the fact that it is claimed that

compliance with this document may involve the use of a patent concerning recalibrating a multi-colour imaging

system given in 4.3.

ISO takes no position concerning the evidence, validity and scope of this patent right.

The holder of this patent right has assured ISO that he/she is willing to negotiate licences free of charge with

applicants throughout the world. In this respect, the statement of the holder of this patent right is registered

with ISO. Information may be obtained from:
Intellectual Property Standards and Transactions
Eastman Kodak Company
343 State Street, Rochester, NY 14650, USA
© ISO 2009 – All rights reserved v
---------------------- Page: 7 ----------------------
SIST-TS ISO/TS 10128:2010
ISO/TS 10128:2009(E)

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights other than those identified above. ISO shall not be held responsible for identifying any or all such patent

rights.
vi © ISO 2009 – All rights reserved
---------------------- Page: 8 ----------------------
SIST-TS ISO/TS 10128:2010
TECHNICAL SPECIFICATION ISO/TS 10128:2009(E)
Graphic technology — Methods of adjustment of the colour
reproduction of a printing system to match a set of
characterization data
1 Scope

This Technical Specification specifies three methods for the adjustment of the digital content data that is input

to a printing system to achieve consistency in the printed results among a number of presses printing to the

same general aim conditions. These three methods are generally identified as
a) the matching of tone value curves,
b) the use of near-neutral scales, and
c) the use of CMYK to CMYK multi-dimensional transforms.

The procedures for establishing the aim condition for the necessary transfer curves, the procedures for

determining the individual transfer curves, and a comparison of the applicability of these three methods are

included.

These adjustment procedures are applicable to printing systems that use CMYK colourants but are not

restricted to those that use traditional ink on paper printing but can involve other marking technologies such as

those used for proofing and/or digital printing.
2 Normative references

The following referenced documents are indispensable for the application 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.

ISO 12642-1, Graphic technology — Input data for characterization of 4-colour process printing — Part 1:

Initial data set

ISO 12642-2, Graphic technology — Input data for characterization of 4-colour process printing — Part 2:

Expanded data set

ISO 13655, Graphic technology — Spectral measurement and colorimetric computation for graphic arts

images

ISO 15076-1, Image technology colour management — Architecture, profile format and data structure —

Part 1: Based on ICC.1:2004-10
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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3.1
adjustment of a printing system with digital data

systematic modification of the content data received, to enable the results printed on a specific device to

match the appearance of the same content data as would have been printed on a reference device

3.2
digital printing

printing directly from digital data when there is no intermediate image carrier, or when the image carrier is

refreshed for each impression, and thus each impression can be different in content if desired

3.3
grey balance

set of tone values for cyan, magenta and yellow that are expected to appear as an achromatic grey under

specified viewing conditions when printed using the specified printing conditions

NOTE 1 Adapted from ISO 12647-1.

NOTE 2 The user can choose between the following two practical definitions and one theoretical definition of grey,

depending upon the particular context:
a) practical definitions:
1) a colour having the same CIELAB a* and b* values as the print substrate;

2) a colour that has the same CIELAB a* and b* values as a half-tone tint of similar L* value printed with black ink;

b) theoretical definition: the colorimetric definition of grey is when the CIELAB a* and b* values both equal 0.

3.4
tone value

proportional printing value encoded in a data file and interpreted as defined in the file format specification

NOTE 1 Most files store these data as 8-bit integer values, i.e. 0 to 255. The tone value, A, expressed as a percentage

of a pixel, is typically computed from the equation
⎛⎞VV−
A=×100
VV−
⎝⎠100 0
where
V is the integer value of the pixel in the file;
V is the integer value corresponding to a tone value of 0 %;
V is the integer value corresponding to a tone value of 100 %.
100
NOTE 2 Adapted from ISO 12647-1.
3.5
tone value increase

difference between the tone value in the digital data file and the tone value on the printed sheet

NOTE Adapted from ISO 12647-1.
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4 Procedures
4.1 General
4.1.1 Overview

Printing standards, in general, specify the ink and paper to be used and the process control parameters in

colorimetric terms. When the inks are well characterized, densitometric aims may also be included for

reference. The ISO 2846 series of International Standards provides the mechanism to specify the colour and

transparency of the ink. Specification of paper is not well defined and is generally limited to an identification of

colour, translucency or grammage, and a reference to industry grades or classifications.

The outer gamut of the printable colour volume is primarily defined by the combination of the colour of the

paper, the colour of solids of the primary inks and of the overprinted solids of two primary inks, and the colour

of the overprinted solids of three primary inks in combination with the black ink. These are included in the

printing conditions defined in the ISO 12647 series of International Standards and are also typically included in

other printing specifications along with reference aims for densitometric data and tone value increase.

Characterization data associated with such printing standards is usually prepared from print test data or data

from earlier tests. In either case, it is typically modified and smoothed so as to match the specified values for

the aim parameters and to represent smooth transitions within the colour volume.

In some situations, a printing system can be adjusted to match a reference by adjusting tone value increase to

match the reference. The principal assumptions are

a) if the primary and secondary colour solids are correct, the outer printing gamut is correct,

b) if the tone curves for the individual single colour scales match those of the reference printing condition,

then the internal overprint data will also match the reference, and

c) within limits, differences in the tone value increase between presses (or between a press and the

reference printing condition) can be compensated for by a series of single channel changes in the input

tone values.

It is, of course, assumed that the paper and ink comply with the specifications for the printing standard being

matched within reasonable tolerances.

The first two methods described in this Technical Specification use such single channel changes and differ

only in the procedure used to determine the individual channel corrections.

The third method assumes that there is sufficient interaction between channels that a series of single channel

corrections are not sufficient. It makes use of an ICC device-link transform (or other mechanism which maps

the device-dependent printing data of one system into the device-dependent printing data of another system)

which essentially is a predefined four-dimensional transform. The reason that an ICC device-link is used

instead of classic ICC colour management is that the transforms included in a device-link profile can be tuned

to preserve the black channel (single colour black stays as a single colour). Classic ICC colour management

converts the CMYK data back into profile connection space (PCS) data and then re-computes the individual

colour separations to create a new set of CMYK data.

All three methods depend on the use of the specified paper and ink, and on achieving the correct colorimetric

values of the process colour solids and two-colour overprint solids.

Although the descriptions that follow refer to the “press to be used for actual printing”, it is recognized that

often process control within an organization is sufficiently managed or that presses belonging to a single

“family” (e.g. same brand or similar models) are sufficiently similar that the same set of corrections can be

applied in a broader sense than simply to a single press. Furthermore, although the term press is used

throughout this document to refer to the intended printing device, these procedures may be used with proofing

devices or with digital printing devices operated in traditional half-tone, continuous tone, or non-traditional

imaging modes.
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4.1.2 Printing specifications

Whenever possible, printing standards should use the printing conditions defined in the applicable part of

ISO 12647, or should be based on these conditions.
4.1.3 Ink specifications

The various parts of ISO 12647 specify use of inks based on the appropriate part of ISO 2846. However, even

when the printing specifications used are not based on ISO 12647, the ink specified should be based on the

appropriate part of ISO 2846 or use similar testing procedures for its definition.

4.1.4 Characterization data

All characterization data should be based on the ink value data sets defined in either ISO 12642-1 or

ISO 12642-2. Measurement of printed samples of these ink value data sets shall be accomplished in

accordance with ISO 13655. Colour management profiles based on such characterization data shall be

created in accordance with ISO 15076-1.
4.1.5 Determination of tone value

Tone value is traditionally calculated from reflectance density data and is an estimate of the percentage of the

surface which appears to be covered by a uniform layer of a colorant of a single colour (if light scattering in the

substrate and other optical phenomena are ignored). The choice of which reflectance density filter set to use

(reflectance density status as defined in ISO 5) is generally not an issue as long as both the reference

characterization data and the press evaluation data are based on the same reflectance density status (as

defined in ISO 5).

Use of a spectrophotometer, adjusted so that its spectral pass band is centred on the wavelength region

where the print exhibits its maximum light absorbance, provi
...

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