ISO/DIS 12647-8

Graphic technology -- Process control for the production of half-tone colour separations, proof and production prints

Technologie graphique -- Contrôle des processus de confection de sélections couleurs tramées, d'épreuves et de tirages

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 12647-8
ISO/TC 130 Secretariat: SAC
Voting begins on: Voting terminates on:
2020-07-29 2020-10-21
Graphic technology — Process control for the production
of half-tone colour separations, proof and production
prints —
Part 8:
Validation print processes working directly from digital data

Technologie graphique — Contrôle des processus de confection de sélections couleurs tramées, d'épreuves

et de tirages —

Partie 8: Processus d'impression de maquette couleur produite à partir de données numériques

ICS: 37.100.01
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
This document is circulated as received from the committee secretariat.
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 12647-8:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
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ISO/DIS 12647-8:2020(E)
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© ISO 2020

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

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ii © ISO 2020 – All rights reserved
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ISO/DIS 12647-8:2020(E)
Contents Page

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

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

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

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

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

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

4.1 Data requirements for validation print systems ........................................................................................................ 2

4.2 Validation print ....................................................................................................................................................................................... 2

4.2.1 Validation print substrate qualification colour and gloss ............................................................ 2

4.2.2 Coloration of printed parts ..................................................................................................................................... 3

4.2.3 Short- and long-term repeatability .................................................................................................................. 4

4.2.4 Permanence ...................................................................... .................................................................................................... 5

4.2.5 Ink set gloss .......................................................................................................................................................................... 6

4.2.6 Tone value reproduction limits ........................................................................................................................... 6

4.2.7 Tonality assessment ...................................................................................................................................................... 6

4.2.8 Reproduction of vignettes ........................................................................................................................................ 6

4.2.9 Image resolving power ............................................................................................................................................... 6

4.2.10 Margin information ....................................................................................................................................................... 7

5 Test methods ............................................................................................................................................................................................................. 7

5.1 System validation .................................................................................................................................................................................. 7

5.2 Validation print control strip ...................................................................................................................................................... 7

5.3 Additional test objects ...................................................................................................................................................................... 8

5.4 Uniformity measurement .............................................................................................................................................................. 8

5.5 Colour measurement ......................................................................................................................................................................... 8

5.6 Measurement of gloss ....................................................................................................................................................................... 9

5.7 Supplementary visual control element .............................................................................................................................. 9

Annex A (normative) Technical requirements for validation print conformity ..................................................10

Annex B (informative) Determination of print durability after stabilization ........................................................12

Annex C (normative) Surface gamut patches ............................................................................................................................................15

Bibliography .............................................................................................................................................................................................................................21

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ISO/DIS 12647-8:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

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

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

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

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

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

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

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

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

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

iso/ foreword .html.

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

This second edition cancels and replaces the first edition (ISO 12647-8:2012), which has been

technically revised.
The main changes compared to the previous edition are as follows:
— Replacing CIE 1976 ∆E with modern ∆E colour difference formulae;
ab 00

— Adding the better metric for uniformity assessment namely the measurement of 1D distortions of

macroscopic uniformity utilizing scanning spectrophotometers;
— Adding a more content oriented control wedge;

— Aligned content with ISO 12647-7 in particular with respect to substrate categorisation and

conformance assessment (new Annex A);

— Removing informative metrics that proved to be not practical such as tonalityA list of all parts in the

ISO 12647 series can be found on the ISO website.

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

complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO/DIS 12647-8:2020(E)
Introduction

This part of ISO 12647 specifies the properties, and associated test methods, required for digital prints

and printing processes to meet the criteria established for “validation prints”.

In most printing workflows, there is a requirement for a visual representation of the expected

appearance of the document being printed that can be used as part of the agreement between customer

and printer. Where this visual representation is produced such that its characteristics (colour fidelity,

tone reproduction, registration, size, etc.) simulate those of the expected printing within tight

tolerances, it is usually referred to as a “contract proof”. As the name implies, contract proofs are used as

part of the contractual relationship between customer and printer and are used as a visual aim for the

press operator during printing as well as the absolute reference against which the finished production

is compared. Not unexpectedly, systems that can produce contract proofs are usually expensive and

require careful operation and maintenance. ISO 12647-7 specifies the requirements for contract proofs

and systems used to produce contract proofs directly from digital data.

Recently, other visualizations of the final printed product have found a place in the printing/proofing

workflow because designers and print buyers prefer not go to the expense of using an ISO 12647-7

compliant contract proof any earlier in the process than necessary. In many situations, participants in

the workflow require a hardcopy visual reference of lesser quality than a contract proof. In the past,

those prints varied widely in quality and were often referred to as design proofs, concept proofs, layout

prints, etc. That quality level is here being referred to as a “validation print”.

Because data are exchanged electronically and visualizations of those data are produced at multiple sites,

there is a requirement for defined requirements for validation prints to allow a degree of consistency

throughout the workflow. One of the goals of having less stringent requirements, particularly on colour

fidelity, is to allow the production of validation prints on less elaborate and less costly devices than are

required for contract proofs. The requirements for validation prints and the systems used to produce

validation prints are documented in this part of ISO 12647.

Validation prints are not intended to replace “contract proofs” for predicting colour on production

printing devices. It is expected that the modifications of the requirements for validation prints, along

with the requirements for contract proofs, will continue in the future as industry requirements and

imaging technologies develop.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 12647-8:2020(E)
Graphic technology — Process control for the production
of half-tone colour separations, proof and production
prints —
Part 8:
Validation print processes working directly from digital data

IMPORTANT — The electronic file of this document contains colours which are considered to be

useful for the correct understanding of the document. Users should therefore consider printing

this document using a colour printer.
1 Scope

This part of ISO 12647 specifies requirements that can be used for determining the conformance of

systems that produce a hard-copy validation print, directly from digital data, which is intended to

simulate the expected appearance of material printed in accordance with a characterized printing

condition.

It is not intended for use in determining the conformance of production printing systems (digital or

conventional) since many aspects of production printing are not covered in this part of ISO 12647.

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 reference

document (including any amendments) applies.
ISO 3664:2009, Graphic technology and photography — Viewing conditions

ISO 8254-1, Paper and board — Measurement of specular gloss — Part 1: 75 degree gloss with a converging

beam, TAPPI method

ISO 12040, Graphic technology — Prints and printing inks — Assessment of light fastness using filtered

xenon arc light

ISO 12640-1:1997, Graphic technology — Prepress digital data exchange — Part 1: CMYK standard colour

image data (CMYK/SCID)

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

Expanded data set

ISO 12647-1, Graphic technology — Process control for the production of half-tone colour separations,

proof and production prints — Part 1: Parameters and measurement methods

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

arts images

ISO/TS 18621-21, Graphic Technology — Image quality evaluation methods for printed matter — Part 21:

Measurement of 1D distortions of macroscopic uniformity utilizing scanning spectrophotometers

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 12647-1 and the following apply.

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ISO/DIS 12647-8:2020(E)
3.1
validation print substrate
printing substrate used for validation print processes

Note 1 to entry: to entry A validation print substrate is usually characterized by its light fastness or permanence

properties, with only essential requirements dictated by the printing process.
3.2
print stabilization period
time after which the colour does not change anymore

Note 1 to entry: to entry It is necessary that this property of the validation print system be specified by the

manufacturer.
3.3
validation print

print produced directly from digital data early in the production chain meeting the requirements of

this part of ISO 12647 representative of the concept for the final product

Note 1 to entry: to entry A validation print can have reduced accuracy compared to contract proof.

3.4
production substrate
intended substrate to be used for production printing

Note 1 to entry: to entry A production substrate can also be a substrate that is originally intended for the

Validation Printing press under test such as a paper with an ink receiving layer or a paper optimized for

electrophotographic printing.
3.5
PDF/X

title of a series of ISO standards regarding the use of the Portable Document Format (PDF) for the

dissemination of digital data intended for print reproduction
4 Requirements
4.1 Data requirements for validation print systems

Validation print systems shall accept digital data delivered as PDF/X data files in accordance with

one of the conformance levels defined in ISO 15930 (parts 1, 4, 6, 7, 8 or 9). Where the digital data is

delivered as PDF/X data files, the intended printing condition being simulated shall be that defined in

the OutputIntents array of the PDF/X file. Where a profile is required for data conversion, the profile

that is the value of the DestOutputProfile key in the PDF/X file shall be used. In case of multi primary

based printing conditions (e.g. 5C, 6C, 7C or 8C) data should be delivered as PDF/X-5n. Since this is

currently not industrial common the sender and receiver shall agree on the pertinent data exchange.

NOTE There are number of industry test suites for testing PDF/X conformance such as The Ghent PDF Output

Suite 4.0 or 5.0 [12] or the Altona Test Suite [14].
4.2 Validation print
4.2.1 Validation print substrate qualification colour and gloss

In an ideal situation the validation print substrate should be the same as the production substrate. As

this ideal situation is seldom possible, the following criteria apply for the validation print substrate:

a) The gloss level of both the printing substrate and validation print substrate should be estimated

as one of Matte, Semimatte or Gloss either by the substrate manufacturer or by measuring as

described in 5.6. Matte substrates should not be used to make validation prints for Gloss printing

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ISO/DIS 12647-8:2020(E)

substrates and Gloss substrates should not be used to make validation prints for Matte printing

substrates.

b) The white point of the unprinted validation print substrate shall allow a colorimetric match of the

substrate of the intended printing condition to be simulated with a colour difference of less than or

equal to 3,0 ΔE units when measured according to ISO 13655.

NOTE 1 To assure a white point match, the validation print substrate should have a CIE L* value that is

higher than the substrate of the printing condition to be simulated.

c) The validation print substrate should belong to the same fluorescence classification as the

production substrate. Fluorescence classification in four levels of faint, low, moderate, and high

shall be made using the testing procedures described in ISO 15397 Clause 5.12.

NOTE 2 ). Fluorescence (difference UV-UVX, colloquially known as ΔB) as defined in ISO 15397 is

calculated by measuring D65 Brightness evaluated as per ISO 2470-2 [15] with UV included (UV) and

UV excluded (UVex) and taking the difference UV - UVex (see ISO 15397 for details). Usual categories for

Fluorescence are: faint, low, moderate and high. In practice it is often useful to add an OBA free category in

which case the faint category is split into OBA free and faint. The categories and ranges for each are shown

in the table below.
Table 1 — Fluorescence categories and ranges
Category name Range
OBA free 0 ≤ ∆B ≤ 1
faint 1 < ∆B ≤ 4
low 4 < ∆B ≤ 8
moderate 8 < ∆B ≤ 14
high 14 < ∆B ≤ 25
4.2.2 Coloration of printed parts
4.2.2.1 Validation print system within sheet uniformity

The variability of the coloration across the validation print format shall be verified by printing each

of the three test forms described in 5.4. Each test form shall be measured at nine locations on each

sheet as follows. Divide the printed area into thirds both horizontally and vertically and measure at

the centre of each area. All selected locations across the printed test area for each test tint, after the

stabilization period, shall have the following:
a) standard deviation less than or equal to 1,5 for CIE L*, a* and b*;

b) maximum ∆E colour difference less than or equal to 2 units between the average of the 9 readings

and any one reading.

NOTE The requirements specified in a) and b) are not statistically consistent but have been observed to be

achievable in a well-controlled digital printing system.

The uniformity shall also be measured by using the to ’Macro-Uniformity-Score’ method defined

in ISO/TS 18621-21, also known as M-Score. Three tone value combinations specified in 5.4 shall be

evaluated as the uniformly tinted area. The ’Macro-Uniformity-Score’ shall be greater than or equal to

50 and should be greater than or equal to 60.
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ISO/DIS 12647-8:2020(E)
4.2.2.2 Colour simulation requirements for validation prints

The CIELAB colour coordinates of the patches of the ISO 12642-2 target and the validation print control

strip defined in 5.2 shall agree with the aim values of the printing condition being simulated as given by

the data (see 4.1) within the appropriate tolerances specified in Table 2.

NOTE 1 The colorimetric aim values for all patches are included in, or can be derived from, the colorimetric

values of the reference characterization data set.

Table 2 — Tolerances for reproduction of all patches in the validation print described in

Clause 5 by comparison to the values of the characterization data of the printing condition

being simulated
Unit: 1
Patch in validation print form Tolerance
ΔE ≤ 3,0
Substrate
95th percentile: ΔE ≤ 5,0
All patches described in 5.2 (without the boundary 00
patches)
Average: ΔE ≤ 2,5
Average: ≤ 2,5
Patches described in 5.2 c
Maximum: ΔC ≤ 4,0
Selected surface gamut patches as listed in Annex B
Average: ΔE ≤ 3,0
(taken from ISO 12642-2)
Average: ΔE ≤ 2,5
All patches described in ISO 12642-2
95th percentile: ΔE ≤ 5,0
Spot colours (solids) ΔE ≤ 3,5

For Multicolour reference printing conditions only the patches in 5.2 shall be used.

NOTE 2 These tolerances apply only to conformance of validation prints as defined in Annex A1 and A2. They

can also be used for validation prints made for a particular printing condition when tested in the field using only

a control wedge. They might be inappropriate as tolerances for daily use at production sites due to the increased

production costs required to maintain the equipment in this optimum state..

NOTE 3 It is expected that validation printing system can also reproduce solid spot colours, provided that a

clear identification by the CIELAB colour or spectral definition such as ISO 17972-4 (CxF/X-4).

NOTE 4 Only when spot colour availability is declared, the declared spot colours are evaluated.

4.2.3 Short- and long-term repeatability

Three validation prints containing at least the primary and CMY secondary colour solids, and primary

colour mid-tones shall be produced. There shall be a 1 hour time difference between the production of

the first and second print and a one day time difference between the first and third validation print.

Recalibration before production of each print is permitted. For each print, measurements shall be made

on the first print produced after the vendor-specified warm-up period. The maximum CIEDE2000

CIELAB colour difference between any two of the three samples of each colour shall not exceed the

values shown in Table 3.
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ISO/DIS 12647-8:2020(E)
Table 3 — Repeatability of primary and CMY secondary colour solids
and primary colour mid-tones (CIEDE2000 -colour differences)
Unit: 1
Mid-tones
Type Solids
(40 % to 50 %)
Validation print 2,0 2,5

NOTE For certain print systems, the same point on a validation print can be formed from a different source

on different days; strictly speaking, this is testing reproducibility not repeatability. For these systems, there is no

true test of repeatability.
4.2.4 Permanence
4.2.4.1 Print stabilization period

A test should be performed and reported to verify that the print colorant has sufficient resistance to

a defined mechanical abrasion after any manufacturer's defined stabilization period. One optional

test method is specified in Annex B. In any test, the time required for the validation print solids to

reach mechanical stability should not exceed the manufacturer’s defined stabilization period. In the

case that there is no manufacturer’s defined stablization period, it should not exceed 30 min. This

test should be performed for each separate combination of materials, driving software, colorant and

printing condition that potentially can change the print stabilization time. If the validation print has

been coated, this shall be reported.
4.2.4.2 Fading and Light fastness testing

Fading testing shall use the solid tones of the C,M,Y,R,G,B plus K (7 patches). The measurement condition

shall be in accordance with ISO 13655:2016 M1 with white backing. Colorimetric calculation shall be in

accordance with ISO 13655.

The validation print stabilization period shall be specified by the manufacturer. The variability

(“fading”) of the C,M,Y,R,G,B plus K patches over time, in the dark, shall not exceed 1,5 ∆E colour

difference units during the first 24 hours after the print stabilization period.

Four copies of a test form shall be prepared on the validation print substrate, which contain unprinted

parts and patches of printed primaries and CMY secondaries both as solids and as midtones.

Combinations of all of the process colours used by the validation printing system shall be included in

this set, which may include more than four colorants.

Three copies of the test form shall be stored for a print stabilisation period of at least 24 hours in the dark

under standard atmosphere according to ISO 187 (at 23°C ± 1°C and a relative humidity of 50% ± 2% RH).

The CIELAB colour values of the proofing substrate and the printed patches shall be measured according

to ISO 13655 M0, M1 or M2 on white backing.

Each of the three copies of the test form shall be subjected to one of the following storage conditions:

a) 24 h at 25°C ±1°C and at a relative humidity of 25% ± 2% in the dark.
b) 24 h at 40°C ±1°C and at a relative humidity of 80% ± 2% in the dark.
c) One week at 40°C ±1°C and at a relative humidity of 10% ± 2% in the dark.

For each of these treatments, for the substrate and for all patches of the test form the maximum colour

difference between colour values of the patches before and after the treatment shall not exceed 4,5

ΔE units.

In cases where validation prints are expected to be used for a longer period of time, light fastness

exposure shall be performed using a window glass filtered xenon lamp. It shall meet a light fastness

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ISO/DIS 12647-8:2020(E)

rating of 3 or greater using the blue wool test as described in ISO 12040. This corresponds to a dose of

43000 kJ/m and a colour difference of ΔE < 4,5

NOTE 1 The reader should be aware that production printing substrates and inks are usually less stable than

typical inkjet-based validation printing substrates and inks. However in this case it is expected that the validation

print is stable over time and does not reflect this specific behaviour. It is expected that a typical validation print

is not used longer than 3 months, hence a lightfastness test is only informative.

NOTE 2 It is anticipated that window glass application as described in ISO 105-B02 [16]: e.g., optical filters be

fitted to minimize short-wavelength light (less than 310 nm).
4.2.5 Ink set gloss

The gloss of solid tone colours should be identical to that of the production print to be simulated. The

ink set gloss may be specified if deemed necessary; see 5.6 for the method.

NOTE If the gloss of the final validation print is substantially different from the expected production print, a

surface-finishing step (e.g. surface laminate) to raise or lower the gloss can improve the situation.

4.2.6 Tone value reproduction limits

Tints intermediate between the (simulated) substrate white and solid shall transfer onto the validation

print in a consistent and uniform manner over a tone value range that includes at least the tone

reproduction limits of the printing condition being simulated; see the pertinent part of ISO 12647 for

this in
...