SIST ISO 2846-3:2005

SLOVENSKI STANDARD
SIST ISO 2846-3:2005
01-januar-2005
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Graphic technology -- Colour and transparency of printing ink sets for four-colour-printing
-- Part 3: Publication gravure printing
Technologie graphique -- Couleur et transparence des gammes d'encre d'impression en
quadrichromie -- Partie 3: Impression hélio
Ta slovenski standard je istoveten z: ISO 2846-3:2002
ICS:
17.180.20 Barve in merjenje svetlobe Colours and measurement of
light
87.080 Barvila. Tiskarske barve Inks. Printing inks
SIST ISO 2846-3:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 2846-3:2005

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SIST ISO 2846-3:2005


INTERNATIONAL ISO
STANDARD 2846-3
First edition
2002-10-01


Graphic technology — Colour and
transparency of printing ink sets for four-
colour-printing —
Part 3:
Publication gravure printing
Technologie graphique — Couleur et transparence des gammes d'encre
d'impression en quadrichromie —
Partie 3: Impression hélio




Reference number
ISO 2846-3:2002(E)
©
 ISO 2002

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SIST ISO 2846-3:2005
ISO 2846-3:2002(E)
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©  ISO 2002
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ii © ISO 2002 – All rights reserved

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SIST ISO 2846-3:2005
ISO 2846-3:2002(E)
Contents Page
Foreword . iv
Introduction. v
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 2
4 Test method. 2
4.1 Principle. 2
4.2 Test print preparation . 2
4.3 Colour measurement procedure. 3
5 Colour and transparency. 3
5.1 General. 3
5.2 Colorimetric values. 3
5.3 Transparency characteristics. 4
Annex A (normative) Reference substrate. 5
Annex B (informative) Spectral data . 6
Annex C (informative) Colorimetric values for non-normative conditions. 9
Annex D (informative) Detailed explanation of the test method, including examples. 10
Bibliography. 13

© ISO 2002 – All rights reserved iii

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SIST ISO 2846-3:2005
ISO 2846-3:2002(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 3.
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.
Attention is drawn to the possibility that some of the elements of this part of ISO 2846 may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 2846-3 was prepared by Technical Committee ISO/TC 130, Graphic technology.
ISO 2846 consists of the following parts, under the general title Graphic technology — Colour and transparency of
printing ink sets for four-colour-printing:
 Part 1: Sheet-fed and heat-set web offset lithographic printing
 Part 2: Coldset offset lithographic printing
 Part 3: Publication gravure printing
 Part 4: Screen printing
 Part 5: Flexographic printing
Annex A forms a normative part of this part of ISO 2846. Annexes B to D are for information only.

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SIST ISO 2846-3:2005
ISO 2846-3:2002(E)
Introduction
The demand for the publication gravure printing process to become more consistent and predictable has required a
means of standardizing the product to ensure the easy flow of business between the various parties involved in its
production. An essential component in this process is the colorimetric characteristics of the ink set.
To produce a set of standard four-colour process inks suitable for gravure printing it is necessary to specify a
number of parameters. It is the purpose of this part of ISO 2846 to describe those parameters which affect the
colorimetric characteristics in such a manner that a standard set of inks can be supplied by any ink manufacturer to
any printer who can then supply prints to a print buyer with confidence in the colour of the work produced.
This part of ISO 2846 will allow publication gravure printers to obtain different sets of inks that will produce a similar
colour when printed on the same substrate. In addition, it will allow colour separations for gravure printing to be
based on known colour standards. The colorimetric characteristics specified may only be obtained when the inks
are printed on the reference substrate. However, two inks of the same type that are similar in colorimetric
characteristics and transparency according to this part of ISO 2846 will normally ensure similarity on another
substrate.

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SIST ISO 2846-3:2005

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SIST ISO 2846-3:2005
INTERNATIONAL STANDARD ISO 2846-3:2002(E)

Graphic technology — Colour and transparency of printing ink
sets for four-colour-printing —
Part 3:
Publication gravure printing
1 Scope
This part of ISO 2846 specifies the colour and transparency to be produced by a process colour ink set including
extender intended for four-colour publication gravure printing when printed under specified gravure printing
conditions. It also specifies the test method to ensure conformance.
This part of ISO 2846 does not specify pigments (or spectral reflectance) in order not to preclude developments
which may enable different pigment combinations to be used advantageously while still achieving the colorimetric
requirements specified in this part of ISO 2846.
NOTE This part of ISO 2846 may also apply to certain non-publication gravure applications.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 2846. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 2846 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 535:1991, Paper and board — Determination of water absorptiveness — Cobb method
ISO 536:1995, Paper and board — Determination of grammage
ISO 2144:1997, Paper, board and pulps — Determination of residue (ash) on ignition at 900 °C
ISO 2846-1:1997, Graphic technology — Colour and transparency of ink sets for four-colour-printing — Part 1:
Sheet-fed and heat-set web offset lithographic printing
ISO 6588:1981, Paper, board and pulps — Determination of pH of aqueous extracts
ISO 8254-1:1999, Paper and board — Measurement of specular gloss — Part 1: 75° gloss with a converging
beam, TAPPI method
ISO 8791-4:1992, Paper and board — Determination of roughness/smoothness (air leak methods) — Part 4:
Print-surf method
ISO 13655:1996, Graphic technology — Spectral measurement and colorimetric computation for graphic arts
images
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SIST ISO 2846-3:2005
ISO 2846-3:2002(E)
3 Terms and definitions
For the purposes of this part of ISO 2846, the following terms and definitions apply.
3.1
extension
addition of a transparent material (colorant-free ink) to the ink to reduce the pigment concentration without
significantly influencing the rheological properties of the ink
3.2
press-ready ink
ink that has all necessary components and is at press viscosity
3.3
transparency
ability of an ink film to transmit and absorb light without scattering
NOTE It is generally expressed as some measure of the unwanted scattering.
[ISO 2846-1:1997, 3.5]
4 Test method
4.1 Principle
Each ink shall be printed on the reference substrate described in annex A at a range of colorations obtained by
varying the extension of the press-ready ink. The colours which result shall be measured colorimetrically and the
colour difference between the sample and the pertinent value in Table 1 shall be plotted versus the percentage of
press-ready ink. If one or more samples conform to the values and tolerances specified, and the ink also meets the
transparency criteria, that ink complies to this part of ISO 2846.
Transparency, T, shall be evaluated by printing or applying each of the chromatic process inks on a black substrate
∗
at a range of ink extensions. The CIELAB colour difference, ∆E , shall be determined for each sample, between
ab
the overprinted and unprinted black. The linear regression coefficient (slope of the regression line) between the
percentage by mass of press-ready ink in each of the extended ink samples being tested and colour difference
∗
shall be calculated from a plot of ∆E vs. percentage press-ready ink over a range of extensions. An ink conforms
ab
to this requirement if the transparency, T, which is the reciprocal of the regression coefficient, is negative or greater
than the value specified. For further details, see annex D.
4.2 Test print preparation
4.2.1 Prints for colorimetric evaluation
For each ink to be evaluated, prepare an extension series with 50 %, 60 %, 70 %, 80 %, 90 % and 100 % of
press-ready ink using extender diluted to press viscosity. Apply the series of extended inks to the reference
substrate specified in annex A with a method that produces an even ink film thickness. Examples are printing with a
printability tester for gravure inks or coating applicator. The wet ink film thickness used for the extension series
shall be approximately equal.
The method chosen shall produce a curve that shows a pronounced minimum or a data point which is in
∗
conformance with Table 1 when ∆E is plotted versus percentage of press-ready ink. If the extension series does
ab
not produce such a curve, produce another series of specimens with a different ink film thickness. Produce a higher
ink film thickness if the colour difference decreases with an increasing percentage of press-ready ink. Produce a
lower ink film thickness if the colour difference decreases with a decreasing percentage of press-ready ink.
See annex D for further information.
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SIST ISO 2846-3:2005
ISO 2846-3:2002(E)
4.2.2 Prints for transparency evaluation
Test prints for transparency evaluation shall be produced by printing the inks to be tested over black. The black
∗
shall have a lightness (L ) less than 6 when determined according to ISO 13655.
1)
One appropriate substrate is the contrast card .
Since the CIELAB values of the black need to be established, both when unprinted and overprinted by the
chromatic ink, the measurements of the black alone shall be made prior to overprinting.
The ink to be tested shall then be printed on the substrate such that a range of samples is achieved, each with a
different percentage of press-ready ink.
4.2.3 Drying of test prints
Prior to colour measurement, all samples shall be thoroughly dried.
4.3 Colour measurement procedure
Test prints shall be measured in accordance with ISO 13655, except that a substrate backing consisting of at least
3 sheets of the unprinted reference substrate shall be used.
NOTE The samples are measured spectrally, with a 0°/45° or 45°/0° geometry instrument. For calculation of CIELAB
values and colour differences, CIE 1931 (2°) standard colorimetric observer data are used together with CIE illuminant D .
50
5 Colour and transparency
5.1
...