ISO 2846-5:2005

SLOVENSKI STANDARD
SIST ISO 2846-5:2008
01-januar-2008
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Graphic technology - Colour and transparency of printing ink sets for four-colour printing
- Part 5: Flexographic printing
Ta slovenski standard je istoveten z: ISO 2846-5:2005
ICS:
17.180.20 Barve in merjenje svetlobe Colours and measurement of
light
87.080 Barvila. Tiskarske barve Inks. Printing inks
SIST ISO 2846-5:2008 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 2846-5:2008

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SIST ISO 2846-5:2008


INTERNATIONAL ISO
STANDARD 2846-5
First edition
2005-03-01

Graphic technology — Colour and
transparency of printing ink sets for
four-colour printing —
Part 5:
Flexographic printing
Technologie graphique — Couleur et transparence des gammes
d'encre d'impression en quadrichromie —
Partie 5: Impression flexographique




Reference number
ISO 2846-5:2005(E)
©
ISO 2005

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SIST ISO 2846-5:2008
ISO 2846-5:2005(E)
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©  ISO 2005
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ii © ISO 2005 – All rights reserved

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SIST ISO 2846-5:2008
ISO 2846-5:2005(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 2
4 Requirements . 2
4.1 General. 2
4.2 Colorimetric values. 2
4.3 Transparency characteristics . 3
5 Test methods. 3
5.1 Principle . 3
5.2 Test print preparation. 4
Annex A (informative) Spectral data.5
Annex B (informative) Colorimetric values for non-normative conditions. 8
Annex C (informative) Detailed explanation of the test method, including examples . 9
Annex D (normative) Reference substrate. 12
Bibliography . 13

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SIST ISO 2846-5:2008
ISO 2846-5:2005(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 2846-5 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
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SIST ISO 2846-5:2008
ISO 2846-5:2005(E)
Introduction
The demand for the flexographic printing process to become more consistent and predictable has required
standardization of the process to ensure that the various parties involved in flexographic printing production
are able to control their part of the process in a meaningful way. An essential component in this process is the
specification of the colorimetric and transparency characteristics of the ink set.
The purpose of this part of ISO 2846 is to define the colorimetric and transparency characteristics of standard
sets of flexographic process inks. Standard inks allow flexographic printers to obtain different sets of inks
which will all produce a similar colour when printed on the same substrate (paper, board, plastic, etc.). So, by
meeting the requirements of this part of ISO 2846 a standard set of inks can be supplied by any ink
manufacturer to any printer, who can then supply prints to a print buyer confident that the colour of the work
produced will be that required. In addition, this part of ISO 2846 will allow colour separations for flexographic
printing to be produced to known colour standards.
The colorimetric characteristics specified may only be obtained when the inks are printed on the specified
reference substrate. However, two inks that are similar in colorimetric characteristics and transparency,
according to this part of ISO 2846, will normally ensure similarity between the results obtained when both inks
are printed on another substrate.
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SIST ISO 2846-5:2008

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SIST ISO 2846-5:2008
INTERNATIONAL STANDARD ISO 2846-5:2005(E)

Graphic technology — Colour and transparency of printing ink
sets for four-colour printing —
Part 5:
Flexographic printing
1 Scope
This part of ISO 2846 specifies the colour and transparency to be produced by each ink in a process colour
ink set (including extender) intended for four-colour flexographic printing, when printed under specified
flexographic printing conditions. It also describes the conformance test method.
This part of ISO 2846 does not specify pigments (or spectral reflectance), in order not to preclude
developments that may enable different pigment combinations to be used advantageously, while still
achieving the colorimetric requirements specified in this part of ISO 2846.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 535, Paper and board — Determination of water absortiveness — Cobb method
ISO 536, Paper and board — Determination of grammage
ISO 2144, Paper and board — Determination of residue (ash) on ignition at 900 °C
ISO 2846-1, 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, Paper and board — Measurement of specular gloss — Part 1: 75 degree gloss with a converging
beam, TAPPI method
ISO 8791-4, Paper and board — Determination of roughness/smoothness (air leak methods) — Part 4:
Print-surf method
ISO 13655, Graphic technology — Spectral measurement and colorimetric computation for graphic arts
images
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SIST ISO 2846-5:2008
ISO 2846-5:2005(E)
3 Terms and definitions
For the purposes of this document, 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
T
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]
4 Requirements
4.1 General
For an ink set to conform to this part of ISO 2846 each ink shall meet the specification for colour defined in 4.2,
at some percentage of press-ready ink, as well as the specification for transparency defined in 4.3.
4.2 Colorimetric values
To meet the specification for colour, each ink in the set shall produce a colour that falls within the tolerances
specified for the appropriate colorimetric values given in Table 1, when printed as defined in 5.2.1 at some
percentage of press-ready ink.
Table 1 — Colorimetric values for 0/45 and 45/0 geometry, illuminant D50, 2° observer
Ink CIELAB values Tolerances
L* a* b* ∆E * ∆a* ∆b* ∆L*
ab
Yellow 91,0 − 5,0 95,0 5,0 — — —
Magenta 52,0 71,0 1,0 6,0 — — —
Cyan 58,0 − 38,0 − 45,0 6,0 — — —
a
0,0

Black u 18,0 0,5 0,0 ± 1,5 ± 2,0
− 18,0
a
This means that for black there is no symmetrical tolerance for L* but an upper limit.
NOTE 1 Typical spectral data for inks conforming to this part of ISO 2846 are provided in Annex A. Reference spectral
data for 8°/diffuse (specular included) are also included in Annex A.
NOTE 2 CIELAB data calculated from the CIE 1931 (2°) standard colorimetric observer, together with CIE standard
illuminant D , are included in Annex B for both geometries. CIELAB data for 8°/diffuse or diffuse/8° (specular included)
65
geometry and illuminant D are also included in Annex B.
50
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SIST ISO 2846-5:2008
ISO 2846-5:2005(E)
4.3 Transparency characteristics
To meet the specification for transparency, each ink in the set shall produce a value greater than that
specified in Table 2 when determined according to the principles and test methods outlined in 5.2.
Table 2 — Transparency requirements
Ink Transparency T
Yellow 2
Magenta 5
Cyan 8
For highly transparent inks, the slope of the regression line may be zero or negative. In such a situation the
transparency value, T, meets the specification.
NOTE For further information concerning transparency evaluation using instruments with different geometry
see C.3.2.
5 Test methods
5.1 Principle
Colorimetric conformance is verified by printing each ink on the reference substrate described in Annex D at a
range of colorations obtained by varying the extension of the press-ready ink. The colours of the resultant test
prints are measured and the colour difference determined between the sample and the pertinent value given
in Table 1. If at least one of these samples has a smaller colour difference than that specified in Table 1 the
ink conforms colorimetrically to this part of ISO 2846.
It is often more convenient to determine the colorimetric conformance of an ink by graphic means. This is
achieved by calculating the colour difference (∆E* ) from the values given in Table 1, for each print made
ab
from the extension series and plotting this against the percentage by mass of press-ready ink. The ink
conforms if the resultant curve shows a pronounced minimum which is below the ∆E* value specified in
ab
Table 1. If the ink series does not produce such a curve, another series of specimens should be prepared
starting from a different ink extension. A lower extension should be applied if the colour difference decreases
with an increasing percentage of press-ready ink; a higher extension if the colour difference increases with a
increasing percentage of press-ready ink. See Annex C for further information.
Transparency, T, is determined by printing or applying each of the chromatic process inks on to a black
substrate at a range of ink extensions. The CIELAB colour difference, ∆E* , is determined for each sample,
ab
between the overprinted and unprinted black substrate. These values of ∆E* are plotted against the
ab
percentage by mass of press-ready ink over a range of extensions. The linear regression coefficient (slope of
the regression line) of this plot is determined. An ink conforms to the transparency requirements of this part of
ISO 2846 if the reciprocal of the regression coefficient is greater than the value specified or negative,
see Annex C for further information.
If one or more printed samples of each ink conform to the colorimetric values within the tolerances specified,
and the ink also meets the transparency criteria, that ink can be said to comply to this part of ISO 2846.
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SIST ISO 2846-5:2008
ISO 2846-5:2005(E)
5.2 Test print preparation
5.2.1 Prints for colorimetric evaluation
For each ink to be eval
...