Graphic technology - Colour conformity of printing workflows

ISO 19302 defines the requirements of printing workflows and evaluation methods for their tone and colour reproduction. It applies to any printing process using any colourant, such as CMYK, CMYK with spot, non-CMYK, spot only or multicolour. This document refers and points to international or national standards and can be used to define, evaluate and audit any printing workflow in whole or in part.

Technologie graphique -- Évaluation de la conformité des couleurs des produits imprimés

Grafična tehnologija - Barvna skladnost grafičnih procesov

General Information

Status
Published
Publication Date
10-Mar-2020
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
27-Feb-2020
Due Date
03-May-2020
Completion Date
11-Mar-2020

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INTERNATIONAL ISO
STANDARD 19302
First edition
2018-12
Graphic technology — Colour
conformity of printing workflows
Reference number
ISO 19302:2018(E)
ISO 2018
---------------------- Page: 1 ----------------------
ISO 19302:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

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
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 19302:2018(E)
Contents Page

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

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

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

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

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

4 Printing workflow requirements ........................................................................................................................................................ 3

4.1 Job colour definition ........................................................................................................................................................................... 3

4.1.1 General...................................................................................................................................................................................... 3

4.1.2 Digital file creation ......................................................................................................................................................... 4

4.1.3 Graphic content ................................................................................................................................................................. 4

4.1.4 Spot colour and device colour build ............................................................................................................... 4

4.2 Process colour reproduction ....................................................................................................................................................... 5

4.2.1 Colour management ...................................................................................................................................................... 5

4.2.2 Prepress ................................................................................................................................................................................... 6

4.2.3 Process control .................................................................................................................................................................. 6

4.3 Product colour conformity ........................................................................................................................................................... 7

4.3.1 General...................................................................................................................................................................................... 7

4.3.2 Print control ......................................................................................................................................................................... 7

4.3.3 Colour control..................................................................................................................................................................... 7

5 Printing workflow standards requirements............................................................................................................................ 8

5.1 Job colour definition ........................................................................................................................................................................... 8

5.1.1 Digital file creation ......................................................................................................................................................... 8

5.1.2 Validation print production .................................................................................................................................... 8

5.1.3 Proofing ................................................................................................................................................................................... 8

5.2 Process colour reproduction ....................................................................................................................................................... 8

5.2.1 Colour management ...................................................................................................................................................... 8

5.2.2 Prepress ................................................................................................................................................................................... 9

5.2.3 Prepress for commercial printing ..................................................................................................................... 9

5.2.4 Prepress for packaging printing ......................................................................................................................... 9

5.2.5 Process control .................................................................................................................................................................. 9

5.3 Product colour conformity ........................................................................................................................................................... 9

5.3.1 Print control ......................................................................................................................................................................... 9

5.3.2 Colour control..................................................................................................................................................................10

5.4 Measurement conditions ......... ....................................................................................................................................................10

5.4.1 General...................................................................................................................................................................................10

5.4.2 Measurement conditions for commercial printing .........................................................................11

5.4.3 Measurement conditions for packaging printing .............................................................................11

5.5 Viewing and illumination ............................................................................................................................................................11

5.6 Sampling ....................................................................................................................................................................................................11

6 Scoring schema ...................................................................................................................................................................................................12

7 Reporting ...................................................................................................................................................................................................................12

Annex A (informative) Colour control ..............................................................................................................................................................13

Annex B (informative) Information exchange .........................................................................................................................................14

Annex C (informative) Typical scoring schemas ...................................................................................................................................15

Bibliography .............................................................................................................................................................................................................................17

© ISO 2018 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 19302:2018(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.

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.
iv © ISO 2018 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 19302:2018(E)
Introduction

The printing industry comprises a variety of workflows that produce a variety of printed products. For

tone and colour reproduction, many ISO standards specify aims and tolerances and they are necessary

for the implementation of a colour-managed and standardized workflow.

Even though relevant standards can specify aims and tolerances, the printer’s ability to demonstrate

conformity of their entire production workflow to these standards often becomes a technical issue as

well as a business issue.

Printed colour reproduction quality depends on printing workflow operation. Printing workflow

operation is made up of colour definition (what colour to specify), process colour reproduction

requirements (what to control) and colour conformity (verify the outcome of the process).

There is a need to provide printers, suppliers, customers and independent bodies with guidelines that

will allow them to implement and/or assess a printing workflow in order to achieve and demonstrate

conformity of printed products.
This document recognizes and makes provisions for the following:
a) conditions and test methods for file generation conformity;
b) conditions and test methods for file colour separation conformity;

c) conditions and test methods for spot colour and/or composite colour conformity;

d) conditions and test methods for soft proofing conformity;
e) conditions and test methods for hard proofing conformity;
f) conditions and test methods for viewing conditions conformity;

g) conditions and test methods for the evaluation of process, print and colour conformity with respect

to specified reference printing conditions (RPCs).

This document is applicable to all printing applications including CMYK, CMYK + spot, spot only, non-

CMYK-based processes and multicolour printing.

This document defines the three main production stages of a printed product as follows:

1) colour definition: the first stage where the customer and design services choose the desired brand

and visual colours;

2) colour reproduction: the production process which starts upon reception of the job file and ends

when the job is printed;

3) colour conformity: the stage which is necessary for the evaluation of the conformity of a printed job.

This document provides:

— a reference framework description for a typical standardized printing workflow (CMYK, CMYK

with spot, non CMYK, spot only and multicolour);

— required International Standards applicable at each stage of a standardized printing workflow;

— a description of expected setup, calibration and process control operations required at each stage of

printing workflow according to the appropriate International Standards;

— a definition of test conditions for colour conformity activities when these are not clearly mentioned

in the relevant standard.
© ISO 2018 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 19302:2018(E)
Graphic technology — Colour conformity of printing
workflows
1 Scope

This document defines the requirements of printing workflows and evaluation methods for their tone

and colour reproduction.

It applies to any printing process using any colourant, such as CMYK, CMYK with spot, non-CMYK, spot

only or multicolour.

This document refers and points to international or national standards and can be used to define,

evaluate and audit any printing workflow in whole or in part.
2 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.

ISO 3664, Graphic technology and photography — Viewing conditions
ISO 12646, Graphic technology — Displays for colour proofing — Characteristics

ISO 12647 (all parts), Graphic technology — Process control for the production of halftone colour

separations, proof and production prints

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

arts images
ISO 14861, Graphic technology — Requirements for colour soft proofing systems

ISO 15930 (all parts), Graphic technology — Prepress digital data exchange using PDF

ISO 17972-4, Graphic technology — Colour data exchange format (CxF/X) — Part 4: Spot colour

characterisation data (CxF/X-4)
CIE 15, Colourimetry – Third edition
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

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

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
actual printing condition
APC
printing condition of the actual printing device or printing process
© ISO 2018 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 19302:2018(E)
3.2
colourant

physical substance such as ink or toner which is used alone or as part of a set of colourants in order to

produce a colour
3.3
comp
mock-up

proof formed to the shape of the final product indicating whether or not it is colour accurate

3.4
device colour build
colour destined to be printed using a process colourant combination

Note 1 to entry: It is typically used to define device-specific values that allow reproduction of a colour using only

process colourants.
3.5
preflight check

file inspection to determine that the digital data contained therein will process such that all data can be

accurately imaged to an image carrier or substrate
3.6
print buyer

person or organization that prepares job data and files in order to deliver them to a print service

provider
3.7
print service provider

person or company that receives job data and files for the purpose of printing them

3.8
printing condition

set of primary process parameters which describe the conditions associated with a specific printed

output and define spectrally or colourimetrically aim values

Note 1 to entry: Such parameters include printing process, substrate, colourant, colourant sequence and

screening. Aim values typically comprise colourants and tone reproduction curves description.

Note 2 to entry: For the purposes of colour management, a printing condition should be fully characterized

by giving the relationship between process input values (as stipulated in ISO 12642-2 for CMYK) and the

corresponding measured colourimetric values.
3.9
process colour

colour that is the outcome of a colour separation operation and that typically requires one or more

printing units and process colourants to be reproduced
3.10
process colourant
colourant that is used to print process colours
3.11
reference printing condition
RPC
aim printing condition for the job
2 © ISO 2018 – All rights reserved
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ISO 19302:2018(E)
3.12
metameric index

difference between spectral radiance distributions within the visible spectrum for two specimens with

identical tristimulus values for a given reference illuminant and reference observer

Note 1 to entry: The procedures concerned with a special metamerism index for a change from a reference

illuminant to a test illuminant of different spectral composition, or that for a change from a reference observer

to a test observer of different colour-matching functions, are called the determination of special metamerism

indices.
Note 2 to entry: Requirements for metameric index are specified in CIE 15.

Note 3 to entry: A measure of metamerism for the two specimens is the colour difference between the two

metameric specimens caused by substituting an illuminant, “special metamerism index: change in illuminant”,

and caused by substituting an observer, “special metamerism index: change in observer”. The colour difference is

evaluated using a CIE colour difference formula and it shall be clearly stated which formula has been used.

Note 4 to entry: It is recommended that for two specimens whose corresponding tristimulus values (X1 = X2,

Y1 = Y2, Z1 = Z2) are identical with respect to a reference illuminant and observer, the metamerism index, M, be

set equal to the colour difference ∆E*ab between the two specimens computed for the test illuminant or for the

test observer.
2 2 2
MI =ΔLL**−Δ +Δaa**−Δ +Δbb**−Δ
() () ()
12 12 12
3.13
spot colour

colour typically used for the definition of brand colours or special design effects that is usually chosen

with the intent of being printed using one printing unit and one spot colourant and that is usually not

blended with other colourants
3.14
spot colourant

colourant that is primarily used to print a spot colour even if it can replace or be blended with process

colourants to obtain a specific colour gamut or colour reproduction
3.15
substrate-corrected colourimetric aim
SCCA

colour data that are corrected in order to compensate for the colourimetric difference between

reference substrate and production substrate colours, assuming that the primary difference between

them lies in the colour of the substrates
3.16
system qualification

assessment operation used to qualify the ability of a print device or a printing process to reproduce a

defined colour data set

Note 1 to entry: This qualification, also named “extended scrutiny”, cannot usually be performed by print

providers during production as it requires specific testing conditions and protocols.

4 Printing workflow requirements
4.1 Job colour definition
4.1.1 General

As illustrated in Figure 1, colour definition is the first step of a printing workflow. This is where a brand

owner or a designer chooses the desired spot and visual colours for the printed product.

© ISO 2018 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO 19302:2018(E)
Figure 1 — Universal printing workflow — Job colour definition
4.1.2 Digital file creation

File format shall be mutually agreed between provider and receiver. The print service provider should

provide its customers with a detailed specification detailing the technical properties of the digital files

to be received (e.g. format, resolution, metadata, colour definition). If no agreement is present then files

shall be prepared in conformity with the ISO 15930 series.
4.1.3 Graphic content

Print buyer specifications shall be clearly defined and mutually agreed on with the print service

provider in terms of:
— reference printing condition (RPC);
— conformity (process, print, colour conformity, criteria, aims and tolerances).
4.1.4 Spot colour and device colour build
4.1.4.1 General

Spot colour definition is important because it is often associated with a brand or product identification.

A specific colour can also be defined as a device colour build made of process colourant composite.

4.1.4.2 Spot and device colour for commercial printing

In commercial applications, spot colours shall be defined by colourimetric values (CIELAB, CIELCh) and

should be defined by spectral values.
4.1.4.3 Spot and device colour for packaging printing

In packaging applications spot colours shall be defined by their spectral response curves.

4 © ISO 2018 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 19302:2018(E)
4.2 Process colour reproduction
Figure 2 — Universal printing workflow — Process colour reproduction

As illustrated in Figure 2, the colour reproduction stage of a printing workflow can be divided into

three main areas:
— colour management [adapting PDF RPC to actual printing condition (APC)];
— prepress (printing form preparation);
— process control (print device calibration and conformity).
4.2.1 Colour management
4.2.1.1 Digital file reception

The print service provider should perform a preflight check on files upon job file reception in order

to identify print buyer expectations and intended printing conditions. Any concern shall be notified

immediately to the print buyer.

To enable a reliable colour management, the following job file metadata should be available in PDF XMP

fields or in another machine-readable file format:
— RGB or CMYK working colour space used;
— rendering intents;
— output intent.
4.2.1.2 Proof and validation print

Digital job files should be delivered with digital proofs that conform with the requirements of 5.1.3.2.

If the print service provider has applied any colour conversion or substrate colour correction on the

received file in order to match RPC with APC, a new hard proof should be produced with this modified file.

Hard proof margin information shall clearly mention production date, proofing system information,

date of last calibration, simulation profile or characterization data [including substrate-corrected

colourimetric aim (SCCA) parameters: RPC, reference white point and actual white point].

© ISO 2018 – All rights reserved 5
---------------------- Page: 10 ----------------------
ISO 19302:2018(E)

When no hard proof is available, a validation print should be provided even though it cannot be

considered as a mandatory reference target. It is also common practice in packaging to provide printed

packaging mock-ups and comps.
4.2.2 Prepress

Print production quality also depends on the colour content of a print job. As a consequence, colour

standardization and control of prepress parameters are the key.

A printing form shall be prepared and its physical properties checked for the selected printing process

and printing conditions.

All files, proofs and printing forms should be proofread for content, geometry, structure and colour

separation. Printing form shall also be measured and proper calibration verified. The supporting

documentation shall be easily referenced on a per-job basis.

Prepress operators should have a broad understanding of the print device calibration and

characterization conditions and operations. Tone reproduction curves adjustment and ICC profiles

shall be generated, controlled and updated as frequently as necessary to maintain the consistency and

accuracy of printing conditions.
4.2.3 Process control

Process control is used to verify that print device solids, tone reproduction curves and colour space

conform with the expected APCs.

It is the print service provider's responsibility to choose the most appropriate calibration method (e.g.

tone value increase, neutral print density curve, device link profile) for their printing process.

Process control procedures shall conform with the requirements of the appropriate part of the

ISO 12647 series.

The print service provider shall have a process control procedure and tools in order to measure and

assess APCs.

Process control patches should include the following: solids, overprints, tone scales (highlights,

quartertones, mid-tones, three-quartertones and shadows), grey balance (shadows, three-quarter,

mids, quarters, highlights), slur gauges, inking gauges, size and scrap permitting.

Routine measurements of process, spot and device colours builds shall be documented, stored and

retrievable. All pertinent press-run measurement data shall be documented for future reference and

analysis.
6 © ISO 2018 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 19302:2018(E)
4.3 Product colour conformity
Figure 3 — Universal printing workflow — Product colour conformity
4.3.1 General

To match reference data set and/or spot colour on the actual print device, print colour control should be

checked (see Figure 3).
4.3.2 Print control
Data set conformity shall address the following:
— colour deviation: the difference between aims values and measured values;

— within-sheet uniformity: deviation between different patches with the same device or colour values;

— colour variation: variation of the printing process during the production run.

Individual prints (colour deviation and uniformity) as well as the entire production (colour variation)

shall conform with the agreed aims and tolerances.
4.3.3 Colour control

Spot colour and device colour builds conformity shall address the same deviation, uniformity and

variation criteria as print control (see 4.3.2).
4.3.3.1 Colour control for commercial printing

Conformity of spot colour for commercial printing shall be based on colourimetric measurements and

ΔE2000 difference formulae.
4.3.3.2 Colour control for packaging printing

Conformity of spot colour for packaging printing should be based on spectral measurements, ΔE2000

and the metameric index. Colour targets shall be colourimetric and should be spectrally defined

according to CxF/X file format as specified in the ISO 17972 series.

Documentation containing colour targets (CxF/X files) and approved contract colour proof and

drawdowns with accompanying reports should be press side during all press runs (initial run and

additional reprints). In addition, reruns should have a signed unconverted original (containing process

control targets). Physical samples or digital data shall be collected and should be stored properly.

© ISO 2018 – All rights reserved 7
---------------------- Page: 12 ----------------------
ISO 19302:2018(E)
5 Printing workflow standards requirements
5.1 Job colour definition
5.1.1 Digital file creation

If no agreement is present, digital files shall be prepared in conformity with the ISO 15930 series

(PDF/X). They shall be prepared as specified in ISO 15930-7 (PDF/X-4) for packaging.

For spot colour definition, CXF/X-4 spot colour characterization data with spectral definition as

specified in ISO 17972-4 should be used.
5.1.2 Validation print production

Validation print supplied by the print buyer to the print service provider shall be produced as specified

in ISO 12647-8.
5.1.3 Proofing
5.1.3.1 Soft proof
Soft proofing shall be carried out as specified in ISO 12646 and ISO 1
...

SLOVENSKI STANDARD
SIST ISO 19302:2020
01-april-2020
Grafična tehnologija - Barvna skladnost grafičnih procesov
Graphic technology - Colour conformity of printing workflows
Technologie graphique -- Évaluation de la conformité des couleurs des produits
imprimés
Ta slovenski standard je istoveten z: ISO 19302:2018
ICS:
37.100.01 Grafična tehnologija na Graphic technology in
splošno general
SIST ISO 19302:2020 en

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

---------------------- Page: 1 ----------------------
SIST ISO 19302:2020
---------------------- Page: 2 ----------------------
SIST ISO 19302:2020
INTERNATIONAL ISO
STANDARD 19302
First edition
2018-12
Graphic technology — Colour
conformity of printing workflows
Reference number
ISO 19302:2018(E)
ISO 2018
---------------------- Page: 3 ----------------------
SIST ISO 19302:2020
ISO 19302:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

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
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 19302:2020
ISO 19302:2018(E)
Contents Page

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

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

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

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

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

4 Printing workflow requirements ........................................................................................................................................................ 3

4.1 Job colour definition ........................................................................................................................................................................... 3

4.1.1 General...................................................................................................................................................................................... 3

4.1.2 Digital file creation ......................................................................................................................................................... 4

4.1.3 Graphic content ................................................................................................................................................................. 4

4.1.4 Spot colour and device colour build ............................................................................................................... 4

4.2 Process colour reproduction ....................................................................................................................................................... 5

4.2.1 Colour management ...................................................................................................................................................... 5

4.2.2 Prepress ................................................................................................................................................................................... 6

4.2.3 Process control .................................................................................................................................................................. 6

4.3 Product colour conformity ........................................................................................................................................................... 7

4.3.1 General...................................................................................................................................................................................... 7

4.3.2 Print control ......................................................................................................................................................................... 7

4.3.3 Colour control..................................................................................................................................................................... 7

5 Printing workflow standards requirements............................................................................................................................ 8

5.1 Job colour definition ........................................................................................................................................................................... 8

5.1.1 Digital file creation ......................................................................................................................................................... 8

5.1.2 Validation print production .................................................................................................................................... 8

5.1.3 Proofing ................................................................................................................................................................................... 8

5.2 Process colour reproduction ....................................................................................................................................................... 8

5.2.1 Colour management ...................................................................................................................................................... 8

5.2.2 Prepress ................................................................................................................................................................................... 9

5.2.3 Prepress for commercial printing ..................................................................................................................... 9

5.2.4 Prepress for packaging printing ......................................................................................................................... 9

5.2.5 Process control .................................................................................................................................................................. 9

5.3 Product colour conformity ........................................................................................................................................................... 9

5.3.1 Print control ......................................................................................................................................................................... 9

5.3.2 Colour control..................................................................................................................................................................10

5.4 Measurement conditions ......... ....................................................................................................................................................10

5.4.1 General...................................................................................................................................................................................10

5.4.2 Measurement conditions for commercial printing .........................................................................11

5.4.3 Measurement conditions for packaging printing .............................................................................11

5.5 Viewing and illumination ............................................................................................................................................................11

5.6 Sampling ....................................................................................................................................................................................................11

6 Scoring schema ...................................................................................................................................................................................................12

7 Reporting ...................................................................................................................................................................................................................12

Annex A (informative) Colour control ..............................................................................................................................................................13

Annex B (informative) Information exchange .........................................................................................................................................14

Annex C (informative) Typical scoring schemas ...................................................................................................................................15

Bibliography .............................................................................................................................................................................................................................17

© ISO 2018 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 19302:2020
ISO 19302:2018(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.

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.
iv © ISO 2018 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 19302:2020
ISO 19302:2018(E)
Introduction

The printing industry comprises a variety of workflows that produce a variety of printed products. For

tone and colour reproduction, many ISO standards specify aims and tolerances and they are necessary

for the implementation of a colour-managed and standardized workflow.

Even though relevant standards can specify aims and tolerances, the printer’s ability to demonstrate

conformity of their entire production workflow to these standards often becomes a technical issue as

well as a business issue.

Printed colour reproduction quality depends on printing workflow operation. Printing workflow

operation is made up of colour definition (what colour to specify), process colour reproduction

requirements (what to control) and colour conformity (verify the outcome of the process).

There is a need to provide printers, suppliers, customers and independent bodies with guidelines that

will allow them to implement and/or assess a printing workflow in order to achieve and demonstrate

conformity of printed products.
This document recognizes and makes provisions for the following:
a) conditions and test methods for file generation conformity;
b) conditions and test methods for file colour separation conformity;

c) conditions and test methods for spot colour and/or composite colour conformity;

d) conditions and test methods for soft proofing conformity;
e) conditions and test methods for hard proofing conformity;
f) conditions and test methods for viewing conditions conformity;

g) conditions and test methods for the evaluation of process, print and colour conformity with respect

to specified reference printing conditions (RPCs).

This document is applicable to all printing applications including CMYK, CMYK + spot, spot only, non-

CMYK-based processes and multicolour printing.

This document defines the three main production stages of a printed product as follows:

1) colour definition: the first stage where the customer and design services choose the desired brand

and visual colours;

2) colour reproduction: the production process which starts upon reception of the job file and ends

when the job is printed;

3) colour conformity: the stage which is necessary for the evaluation of the conformity of a printed job.

This document provides:

— a reference framework description for a typical standardized printing workflow (CMYK, CMYK

with spot, non CMYK, spot only and multicolour);

— required International Standards applicable at each stage of a standardized printing workflow;

— a description of expected setup, calibration and process control operations required at each stage of

printing workflow according to the appropriate International Standards;

— a definition of test conditions for colour conformity activities when these are not clearly mentioned

in the relevant standard.
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Graphic technology — Colour conformity of printing
workflows
1 Scope

This document defines the requirements of printing workflows and evaluation methods for their tone

and colour reproduction.

It applies to any printing process using any colourant, such as CMYK, CMYK with spot, non-CMYK, spot

only or multicolour.

This document refers and points to international or national standards and can be used to define,

evaluate and audit any printing workflow in whole or in part.
2 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.

ISO 3664, Graphic technology and photography — Viewing conditions
ISO 12646, Graphic technology — Displays for colour proofing — Characteristics

ISO 12647 (all parts), Graphic technology — Process control for the production of halftone colour

separations, proof and production prints

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

arts images
ISO 14861, Graphic technology — Requirements for colour soft proofing systems

ISO 15930 (all parts), Graphic technology — Prepress digital data exchange using PDF

ISO 17972-4, Graphic technology — Colour data exchange format (CxF/X) — Part 4: Spot colour

characterisation data (CxF/X-4)
CIE 15, Colourimetry – Third edition
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

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

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
actual printing condition
APC
printing condition of the actual printing device or printing process
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3.2
colourant

physical substance such as ink or toner which is used alone or as part of a set of colourants in order to

produce a colour
3.3
comp
mock-up

proof formed to the shape of the final product indicating whether or not it is colour accurate

3.4
device colour build
colour destined to be printed using a process colourant combination

Note 1 to entry: It is typically used to define device-specific values that allow reproduction of a colour using only

process colourants.
3.5
preflight check

file inspection to determine that the digital data contained therein will process such that all data can be

accurately imaged to an image carrier or substrate
3.6
print buyer

person or organization that prepares job data and files in order to deliver them to a print service

provider
3.7
print service provider

person or company that receives job data and files for the purpose of printing them

3.8
printing condition

set of primary process parameters which describe the conditions associated with a specific printed

output and define spectrally or colourimetrically aim values

Note 1 to entry: Such parameters include printing process, substrate, colourant, colourant sequence and

screening. Aim values typically comprise colourants and tone reproduction curves description.

Note 2 to entry: For the purposes of colour management, a printing condition should be fully characterized

by giving the relationship between process input values (as stipulated in ISO 12642-2 for CMYK) and the

corresponding measured colourimetric values.
3.9
process colour

colour that is the outcome of a colour separation operation and that typically requires one or more

printing units and process colourants to be reproduced
3.10
process colourant
colourant that is used to print process colours
3.11
reference printing condition
RPC
aim printing condition for the job
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3.12
metameric index

difference between spectral radiance distributions within the visible spectrum for two specimens with

identical tristimulus values for a given reference illuminant and reference observer

Note 1 to entry: The procedures concerned with a special metamerism index for a change from a reference

illuminant to a test illuminant of different spectral composition, or that for a change from a reference observer

to a test observer of different colour-matching functions, are called the determination of special metamerism

indices.
Note 2 to entry: Requirements for metameric index are specified in CIE 15.

Note 3 to entry: A measure of metamerism for the two specimens is the colour difference between the two

metameric specimens caused by substituting an illuminant, “special metamerism index: change in illuminant”,

and caused by substituting an observer, “special metamerism index: change in observer”. The colour difference is

evaluated using a CIE colour difference formula and it shall be clearly stated which formula has been used.

Note 4 to entry: It is recommended that for two specimens whose corresponding tristimulus values (X1 = X2,

Y1 = Y2, Z1 = Z2) are identical with respect to a reference illuminant and observer, the metamerism index, M, be

set equal to the colour difference ∆E*ab between the two specimens computed for the test illuminant or for the

test observer.
2 2 2
MI =ΔLL**−Δ +Δaa**−Δ +Δbb**−Δ
() () ()
12 12 12
3.13
spot colour

colour typically used for the definition of brand colours or special design effects that is usually chosen

with the intent of being printed using one printing unit and one spot colourant and that is usually not

blended with other colourants
3.14
spot colourant

colourant that is primarily used to print a spot colour even if it can replace or be blended with process

colourants to obtain a specific colour gamut or colour reproduction
3.15
substrate-corrected colourimetric aim
SCCA

colour data that are corrected in order to compensate for the colourimetric difference between

reference substrate and production substrate colours, assuming that the primary difference between

them lies in the colour of the substrates
3.16
system qualification

assessment operation used to qualify the ability of a print device or a printing process to reproduce a

defined colour data set

Note 1 to entry: This qualification, also named “extended scrutiny”, cannot usually be performed by print

providers during production as it requires specific testing conditions and protocols.

4 Printing workflow requirements
4.1 Job colour definition
4.1.1 General

As illustrated in Figure 1, colour definition is the first step of a printing workflow. This is where a brand

owner or a designer chooses the desired spot and visual colours for the printed product.

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Figure 1 — Universal printing workflow — Job colour definition
4.1.2 Digital file creation

File format shall be mutually agreed between provider and receiver. The print service provider should

provide its customers with a detailed specification detailing the technical properties of the digital files

to be received (e.g. format, resolution, metadata, colour definition). If no agreement is present then files

shall be prepared in conformity with the ISO 15930 series.
4.1.3 Graphic content

Print buyer specifications shall be clearly defined and mutually agreed on with the print service

provider in terms of:
— reference printing condition (RPC);
— conformity (process, print, colour conformity, criteria, aims and tolerances).
4.1.4 Spot colour and device colour build
4.1.4.1 General

Spot colour definition is important because it is often associated with a brand or product identification.

A specific colour can also be defined as a device colour build made of process colourant composite.

4.1.4.2 Spot and device colour for commercial printing

In commercial applications, spot colours shall be defined by colourimetric values (CIELAB, CIELCh) and

should be defined by spectral values.
4.1.4.3 Spot and device colour for packaging printing

In packaging applications spot colours shall be defined by their spectral response curves.

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4.2 Process colour reproduction
Figure 2 — Universal printing workflow — Process colour reproduction

As illustrated in Figure 2, the colour reproduction stage of a printing workflow can be divided into

three main areas:
— colour management [adapting PDF RPC to actual printing condition (APC)];
— prepress (printing form preparation);
— process control (print device calibration and conformity).
4.2.1 Colour management
4.2.1.1 Digital file reception

The print service provider should perform a preflight check on files upon job file reception in order

to identify print buyer expectations and intended printing conditions. Any concern shall be notified

immediately to the print buyer.

To enable a reliable colour management, the following job file metadata should be available in PDF XMP

fields or in another machine-readable file format:
— RGB or CMYK working colour space used;
— rendering intents;
— output intent.
4.2.1.2 Proof and validation print

Digital job files should be delivered with digital proofs that conform with the requirements of 5.1.3.2.

If the print service provider has applied any colour conversion or substrate colour correction on the

received file in order to match RPC with APC, a new hard proof should be produced with this modified file.

Hard proof margin information shall clearly mention production date, proofing system information,

date of last calibration, simulation profile or characterization data [including substrate-corrected

colourimetric aim (SCCA) parameters: RPC, reference white point and actual white point].

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When no hard proof is available, a validation print should be provided even though it cannot be

considered as a mandatory reference target. It is also common practice in packaging to provide printed

packaging mock-ups and comps.
4.2.2 Prepress

Print production quality also depends on the colour content of a print job. As a consequence, colour

standardization and control of prepress parameters are the key.

A printing form shall be prepared and its physical properties checked for the selected printing process

and printing conditions.

All files, proofs and printing forms should be proofread for content, geometry, structure and colour

separation. Printing form shall also be measured and proper calibration verified. The supporting

documentation shall be easily referenced on a per-job basis.

Prepress operators should have a broad understanding of the print device calibration and

characterization conditions and operations. Tone reproduction curves adjustment and ICC profiles

shall be generated, controlled and updated as frequently as necessary to maintain the consistency and

accuracy of printing conditions.
4.2.3 Process control

Process control is used to verify that print device solids, tone reproduction curves and colour space

conform with the expected APCs.

It is the print service provider's responsibility to choose the most appropriate calibration method (e.g.

tone value increase, neutral print density curve, device link profile) for their printing process.

Process control procedures shall conform with the requirements of the appropriate part of the

ISO 12647 series.

The print service provider shall have a process control procedure and tools in order to measure and

assess APCs.

Process control patches should include the following: solids, overprints, tone scales (highlights,

quartertones, mid-tones, three-quartertones and shadows), grey balance (shadows, three-quarter,

mids, quarters, highlights), slur gauges, inking gauges, size and scrap permitting.

Routine measurements of process, spot and device colours builds shall be documented, stored and

retrievable. All pertinent press-run measurement data shall be documented for future reference and

analysis.
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4.3 Product colour conformity
Figure 3 — Universal printing workflow — Product colour conformity
4.3.1 General

To match reference data set and/or spot colour on the actual print device, print colour control should be

checked (see Figure 3).
4.3.2 Print control
Data set conformity shall address the following:
— colour deviation: the difference between aims values and measured values;

— within-sheet uniformity: deviation between different patches with the same device or colour values;

— colour variation: variation of the printing process during the production run.

Individual prints (colour deviation and uniformity) as well as the entire production (colour variation)

shall conform with the agreed aims and tolerances.
4.3.3 Colour control

Spot colour and device colour builds conformity shall address the same deviation, uniformity and

variation criteria as print control (see 4.3.2).
4.3.3.1 Colour control for commercial printing

Conformity of spot colour for commercial printing shall be based on colourimetric measurements and

ΔE2000 difference formulae.
4.3.3.2 Colour control for packaging printing

Conformity of spot colour for packaging printing should be based on spectral measurements, ΔE2000

and the metameric index. Colour targets shall be colourimetric and should be spectrally defined

according to CxF/X file format as specified in the ISO 17972 series.

Documentation containing colour targets (CxF/X files) and approved contract colour proof and

drawdowns with accompanying reports should be press side during all press runs (initial run and

additional reprints). In
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