SIST ISO 12647-2:1997

Graphic technology -- Process control for the manufacture of half-tone colour separations, proof and production prints -- Part 2: Offset lithographic processes

Specifies some process parameters and their values to be applied when preparing colour separations for four-colour offset printing.

Technologie graphique -- Maîtrise des procédés pour la fabrication des séparations de couleur en ton tramé, des épreuves et des tirages en production -- Partie 2: Procédés offset lithographiques

Grafična tehnologija - Vodenje procesa izdelave rastriranih barvnih izvlečkov, preskusnih in proizvodnih odtisov - 2. del: Procesi v ofsetnem tisku

General Information

• Status: Withdrawn
• Publication Date: 28-Feb-1997
• Withdrawal Date: 31-Dec-2004
• ICS: 37.100.01 - Graphic technology in general
• Technical Committee: GRT - Graphical technology
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 01-Jan-2005
• Due Date: 01-Jan-2005
• Completion Date: 01-Jan-2005
• Ref Project: ISO 12647-2:1996 - Graphic technology — Process control for the manufacture of half-tone colour separations, proof and production prints — Part 2: Offset lithographic processes

Relations

• Revised: ISO 12647-2:2004 - Graphic technology — Process control for the production of half-tone colour separations, proof and production prints — Part 2: Offset lithographic processes
• Effective Date: 12-May-2008
• Replaced By: SIST ISO 12647-2:2005 - Graphic technology -- Process control for the production of half-tone colour separations, proof and production prints -- Part 2: Offset lithographic processes
• Effective Date: 01-Jan-2005

Standards Content (Sample)

INTERNATIONAL
ISO
STANDARD
12647-2
First edition
1996-12-01
Graphit technology - Process control for
the manufacture of half-tone colour
Separations, proof and production prints -
Part 2:
Offset lithographic processes
Technologie graphique - Maîtrise des pro&d& pour Ia fabrication des
Separations de couleur en ton trame, des epreuves et des tirages en
production -
Partie 2: Pro&d& offse t lithographiques
Reference number
ISO 12647-2: 1996(E)

---------------------- Page: 1 ----------------------
ISO 12647=2:1996(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. Esch 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.
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.
International Standard ISO 12647-2 was prepared by Technical Committee
lSO/TC 130, Graphit technology.
ISO 12647 consists of the following Parts, under the general title Graphit
Process control for the manufacture of half-tone colour
technology -
separa tions, proof and production prin ts:
Part 7: Parameters and measurement methods
Part 2: Offset lithographic processes
Annexes A to D of this International Standard are for information only.
0 ISO 1996
All rights reserved. Unless otherwise specified, no part of this publication may be
reproduced or utilized in any form or by any means, electronie or mechanical, including
photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case ?ostale 56 l CH-1 21 IG eneve 20 l Switzerland
Printed in Switzerland
ii

---------------------- Page: 2 ----------------------
Q ISO
ISO 12647-2: 1996(E)
Introduction
When producing a half-tone colour reproduction it is important that the
colour separator, proofer and Printer have previously specified a minimum
set of Parameters that uniquely define the visual characteristics and other
technical properties of the planned print product and the proof. Such an
agreement enables the correct production of suitable Separations (without
recourse to “trial-and-error”) and subsequent production of off-press or on-
press proof prints from these Separations. The purpose of a proof print is
to simulate the visual characteristics of the finished print product as
closely as possible.
In Order to visually match a particular print, off-press proofing processes
may require values for solid tone coloration and tone value increase which
are different from those of the printing process they are meant to
simulate. This is caused by differentes in phenomena such as gloss, light
scatter (within the print Substrate or the colourant), metamerism and
transparency. Such differentes are likely for those off-press proofing
processes in which the print Substrate, the colourants and the technology
for applying them are significantty different from offset press printing. In
such cases the user or the supplier should ensure that appropriate
corrections are specified.
lt is necessary to distinguish between primary and secondary Parameters.
Whereas primary Parameters (as listed in this part of ISO 12647) are
defined as having a direct bearing on the visual characteristics of the
image, secondary Parameters only influence the image indirectly by
changing the values of primary Parameters. Secondary Parameters include
- colour Separation film thickness;
image orientation (wrong-reading or right-reading);
film polarity (negative or positive);
- roughness of the emulsion surface;
- presence of colour marking or register marks.
lt is the purpose of ISO 12647-1 to list and explain the minimum set of
primary process Parameters required to uniquely define the visual
characteristics and related technical properties of a half-tone proof or
production print produced from a set of half-tone Separation films.
This part of ISO 12647 Iists suggested values or sets of values of the
primary Parameters specified in ISO 12647-1 and related technical
properties of a half-tone offset print produced from a set of half-tone
colour Separation films. Where deemed useful, secondary Parameters are
also recommended for specification.

---------------------- Page: 3 ----------------------
@ ISO
ISO 12647=2:1996(E)
Other Parts of ISO 12647 will relate to other printing processes such as
.--
newspaper printing;
- gravure printing;
- Screen printing.

---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD 0 ISO
ISO 12647-2:1996(E)
Process control for the manufacture of
Graphit technology -
half-tone colour Separations, proof and production prints -
Part 2:
Offset processes
1 Scope
This part of ISO 12647 specifies a number of process Parameters and their values to be applied when preparing
colour Separations for four-colour offset printing or when producing four-colour prints by one of the following
methods: heat-set web, sheet-fed or continuous forms process printing, or proofing for these processes; offset
proofing for half-tone gravure. The Parameters and values are Chosen in view of the complete process covering the
“making of the printing forme“, “proof production”, “production printing” and
process stages “colour Separation”,
“surface finishing”.
This part of ISO 12647 is
- directly applicable to proofing and printing processes that use colour Separation films as input;
- directly applicable to proofing and printing from printing surfaces produced by filmless methods and to gravure
printing as long as direct analogies to film production Systems are maintained;
- applicable to proofing with more than four process colours as long as direct analogies to four-colour printing are
maintained;
- applicable by analogy to line screens and non-periodic screens.
2 Normative references
The following Standards contain provisions which, through reference in this text, constitute provisions of this part
of ISO 12647. At the time of publication, the editions indicated were valid. All Standards are subject to revision, and
Parties to agreements based on this part of ISO 12647 are encouraged to investigate the possibility of applying the
most recent editions of the Standards indicated below. Members of IEC and ISO maintain registers of currently
valid International Standards.
ISO 5-3:1995, Photography - Density measurements - Part 3: Spectral conditions.
1) Paper and board - Measurement of specular gloss - Part 1: 75O gloss.
ISO 8254-l:- ,
ISO 12647-1: 1996, Graphit technology - Process con trol for the manufacture of half-tone colour Separations,
proo f and production prints - Part 1: Parameters and measurement methods.
1) To be published.

---------------------- Page: 5 ----------------------
ISO 12647=2:1996(E) @ ISO
3 Definitions
For the purposes of this part of ISO 12647, the definition given in ISO 12647-1 and the following definitions apply.
3.1 offset (printing) plate: Plane workpiece whose surface has been coated such that an offset printing forme
tan be produced thereof.
3.2 positive-acting (offset printing) plate: Offset printing plate for use with positive polarity film.
3.3 negative-acting (offset printing) plate: Offset printing plate for use with negative polarity film.
3.4 four-colour continuous forms printing: Offset process performed on small width web-fed presses for use
with personalized mailings.
3.5 commercial/speciality printing: General purpose sheet-fed and non-magazine heat-set web offset printing.
Screen: Half-tone Screen without a regular Screen angle and without a constant
36 . non-periodic (half-tone)
en ruling.
scre
4 Requirements
The followin are arranged according to the Order set out in ISO 12647-1; they also depend on it for the
g subclauses
definition of the data and measuremen t conditions.
4.1 Colour Separation films
4.1 .l Quality
Unless otherwise specified, the core density shall be at least 2,5 above the transmission density of the clear film
(film base plus fog). The transmission density in the centre of a clear half-tone dot shall not be more than 0,l above
the corresponding value of a large clear area. The transmission density of the clear film shall not be higher than
0,15. Both measurements shall be made with a (UV) transmission densitometer whose spectral products conform
to ISO type 1 printing density as defined in ISO 5-3.
The fringe width shall not be greater than one-fortieth of the Screen width; the half-tone dot shall not be Split up
into distinct Parts. The colour Separation film quality shall be evaluated according to ISO 12647-1, annex B.
NOTES
1 The clear film density requirement is based on the understanding
- that the density range of the clear areas of all films that are to be exposed onto an offset plate, for consistent work,
should not exceed 0,lO;
that 0,05 represents the lowest commonly found value for ISO type 1 printing density.
-
In Order to minimize the impact of the use of half-tone films with clear film densities above this range, agreements between
the supplier of colour Separations and the recipient are required. Contacting or duplicating tan also be used to bring half-tone
films with dissimilar clear film densities into agreement.
2 Asa practi cal guide , a cor ‘e density of 2,5 above the clear film density will normally be
achieved if the density of Iarge solid
areas 1s more than 3,5 a bove the clear film density.
3 If a user wishes to use a blue filter for transmission density measurements it is necessary to determine, for the particular
film type and processing conditions, the correlation between densities obtained with the blue filter and those obtained with an
ISO type 1 printing density instrument; for the measurement of core density an ISO type 2 printing instrciment may be used.
2

---------------------- Page: 6 ----------------------
@ ISO
ISO 12647=2:1996(E)
4.1.2 Screen ruling
For four-colour work, the Screen ruling (Screen frequency) shall be within the range 45 cm-1 to 80 cm-1. Preferred
nominal Screen rulings are:
45 cm-1 to 60 cm-1 for web offset periodical printing;
52 cm-1 to 60 cm-1 for continuous forms process printing;
60 cm-1 to 80 cm-1 for commerciaI/speciaIity printing.
NOTES
1 to 80 cm-1 the general principles specified in ISO 12647-1 remain valid but specific values
4 Outside of the range 45 cm-
may differ.
5 With computer-generated screening, the Parameters “Screen ruling” and “Screen angle” may be varied slightly in
conjuction, from one process colour to another, in Order to minimize moire Patterns.
6 For the black colour half-tone a Screen ruling may be used which is substantially finer than the nominal Screen ruling of the
chromatic colours. For example 80 cm-1 for K and 60 cm-1 for CMY.
4.1.3 Screen angle
For half-tone dots without a principal axis, the nominal differente between the Screen angles for Cyan, magenta,
and black shall be 30°, with the Screen angle of yellow separated at 15” from another colour. The Screen angle of
the dominant colour should be 45”; this value refers to the film.
For half-tone dots with a principal axis, the nominal differente between Screen angles for Cyan, magenta, and black
shall be 60°, with the Screen angle of yellow separated by 15” from another colour. The Screen angle of the
dominant colour should be 45” or 135”; these values refer to the film.
The preparation of colour Separation films for half-tone gravure printing should avoid Screen angles between 75”
and 105” with colours other than yellow.
NOTE 7 See note 5 in 4.1.2.
4.1.4 Dot shape and its relationship to tone value
Circular, Square or elliptical half-tone dot shapes shall be used. For half-tone dots with a principal axis, the first Iink-
up shall occur no Iower than at 40 % tone value and the second link-up no higher than at 60 % tone value.
4.1.5 Image size tolerante
For a set of colour Separation films in common environmental equilibrium, the lengths of the diagonals shall not
differ by more than 0,02 %.
NOTE 8 This tolerante includes image-setter repeatability and film stability.
4.1.6 Tone value sum
Unless otherwise specified, the tone value sum should be less than but shall not exceed 350 % for sheet-fed and
300 % for web-fed printing.
NOTE 9 At high levels of tone value sum press Problems such as poor trapping, back transfer and set-off due to sufficient ink
drying may be encountered.
3

---------------------- Page: 7 ----------------------
ISO 1264792:1996(E)
4.1.7 Grey baiante
Unless otherwise specified, the grey balance should be given by the following tone value combinations.
Yellow
Cyan Magenta
Quarter tone 25 % 19 % 19 %
Mid tone 50 % 40 % 40 %
%
Three-quarter tone 75 % 64 % 64
4.2 Print
42.1 Visual characteristics of image components
4.2.1.1 Print Substrate colour
The print Substrate used for proofing should be identical to that of the production. If this is not possible, the
properties of the print Substrate should be a close match to that of the production in terms of colour, gloss, type of
surface (coated, uncoated, super-calendered, etc.) and mass per area. Press proofing should be carried out on the
closest match selected from five typical Paper types, whose attributes are listed in table 1. For off-press proofing
the print Substrate should be selected to conform as closely as possible to the attributes listed in table 1 of the
Paper type representing the envisaged production Paper. The type of Paper shall be stated.
Table 1
- CIELAB L*, a*, b* values, gloss, brightness and tolerantes for typical Paper types
L* 1) a* 1) b* 1)
Paper type Gloss 2) Brightnessz) Mass per area4)
1 1 %
1 % g/m*
93 0 -3 115
1: Gloss-coated, wood-free 65 85
0
92 -3 38 83 115
2: Matt-coated, wood-free
87 -1 3 70
55 70
3: Gloss-coated, web
-3
92 0 85 115
4: Uncoated, white 6
0 6 115
88 6 85
5: Uncoated, yellowish
Tolerante: +3 &2 L-2 -+5
0 5
95 70-80 80 150
Reference Papers)
1) Measurement according to ISO 12647-1 3996, 5.6: Black backing, D 50 illuminant, 2” observer, 0/45 or 45/O geometry. ’
2) Measurement according to ISO 8254-1.
3) Reflectance at 460 nm, informative only.
4) Informative only.
Paper used for ink set test (see ISO 2846-l), informative only.
5)
NOTES
IO In terms of gloss and colour, the Paper types listed in table 1 represent the corner stones of the range of print Substrates
used for the processes covered in this part of ISO 12647, with the following exceptions:
- the Paper types 1 and 2 are not typical for web-fed magazine printing except for covers;
- Paper types 3 and 5 are not typical for four-colour business forms printing.

---------------------- Page: 8 ----------------------
@ ISO
ISO 12647=2:1996(E)
11 If the final product is to be surface finished, this may severely affect the print Substrate colour. See also note 17 in 4.2.1.2.
12 The L*, a”, b* values for the conditions “065” or “white backing” agree with those specified in table 1 within the
tolerantes specified there.
13 The Parameters of the reference Paper specified in ISO 2846-1 have been included in table 1, for information only, in Order
10 provide a connection to this related International Standard. Note that some values differ from ISO 2846-1 due to the black
backing.
14 The mass per area specified for Paper type 3 represents a compromise between web production Papers with typically
60 g/m* to 65 g/m* and a weil-known web proofing Paper with 90 g/m*. When measured with black backing, the differente
between similar Papers of 70 g/m* and 90 g/m* corresponds to AL,* = 0,7.
15 Although less commonly used, some web Papers in the mass per area range of type 3 Papers have b* values in the range
0 to -3.
421.2 Print Substrate gloss
The gloss of the print Substrate used for proofing should be a close match to that of the production print Substrate.
If this is not possible, press proofing may be carried out on the closest match selected from the Paper types listed
in 4.2.1.1.
NOTES
16 The gloss values of the Paper types described in 4.2.1 .l are given in table 1.
17 If the final product is to be surface finished this will severely affect the gloss. In critical cases, the result of the colour
Separation stage may be best judged by means of a proof that closely matches the gloss of the final surface-finished print
product. In Order to facilitate the matthing of the production image to the proof image at the make-ready Stage, it is a good
plan to provide the production Printer with two proof prints: a proof print whose gloss matches that of the (unfinished)
production print Substrate and a proof print which closely matches the gloss of the final surface-finished print product.
421.3 In k set colours
For the five print Substrates of 4.2.1 .l, the CIELAB colour coordinates L*, a”, b* of the process colour solids on the
proof shall agree with the aim values specified in table 2 within the appropriate deviation tolerantes specified in
table 3. The colour coordinates of the two-colour overprints without black ink should be as given in table 2.
Th
...

SLOVENSKI STANDARD
SIST ISO 12647-2:1997
01-marec-1997
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SUHVNXVQLKLQSURL]YRGQLKRGWLVRYGHO3URFHVLYRIVHWQHPWLVNX
Graphic technology -- Process control for the manufacture of half-tone colour
separations, proof and production prints -- Part 2: Offset lithographic processes
Technologie graphique -- Maîtrise des procédés pour la fabrication des séparations de
couleur en ton tramé, des épreuves et des tirages en production -- Partie 2: Procédés
offset lithographiques
Ta slovenski standard je istoveten z: ISO 12647-2:1996
ICS:
37.100.01 *UDILþQDWHKQRORJLMDQD Graphic technology in
VSORãQR general
SIST ISO 12647-2:1997 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST ISO 12647-2:1997

---------------------- Page: 2 ----------------------

SIST ISO 12647-2:1997
INTERNATIONAL
ISO
STANDARD
12647-2
First edition
1996-12-01
Graphit technology - Process control for
the manufacture of half-tone colour
Separations, proof and production prints -
Part 2:
Offset lithographic processes
Technologie graphique - Maîtrise des pro&d& pour Ia fabrication des
Separations de couleur en ton trame, des epreuves et des tirages en
production -
Partie 2: Pro&d& offse t lithographiques
Reference number
ISO 12647-2: 1996(E)

---------------------- Page: 3 ----------------------

SIST ISO 12647-2:1997
ISO 12647=2:1996(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. Esch 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.
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.
International Standard ISO 12647-2 was prepared by Technical Committee
lSO/TC 130, Graphit technology.
ISO 12647 consists of the following Parts, under the general title Graphit
Process control for the manufacture of half-tone colour
technology -
separa tions, proof and production prin ts:
Part 7: Parameters and measurement methods
Part 2: Offset lithographic processes
Annexes A to D of this International Standard are for information only.
0 ISO 1996
All rights reserved. Unless otherwise specified, no part of this publication may be
reproduced or utilized in any form or by any means, electronie or mechanical, including
photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case ?ostale 56 l CH-1 21 IG eneve 20 l Switzerland
Printed in Switzerland
ii

---------------------- Page: 4 ----------------------

SIST ISO 12647-2:1997
Q ISO
ISO 12647-2: 1996(E)
Introduction
When producing a half-tone colour reproduction it is important that the
colour separator, proofer and Printer have previously specified a minimum
set of Parameters that uniquely define the visual characteristics and other
technical properties of the planned print product and the proof. Such an
agreement enables the correct production of suitable Separations (without
recourse to “trial-and-error”) and subsequent production of off-press or on-
press proof prints from these Separations. The purpose of a proof print is
to simulate the visual characteristics of the finished print product as
closely as possible.
In Order to visually match a particular print, off-press proofing processes
may require values for solid tone coloration and tone value increase which
are different from those of the printing process they are meant to
simulate. This is caused by differentes in phenomena such as gloss, light
scatter (within the print Substrate or the colourant), metamerism and
transparency. Such differentes are likely for those off-press proofing
processes in which the print Substrate, the colourants and the technology
for applying them are significantty different from offset press printing. In
such cases the user or the supplier should ensure that appropriate
corrections are specified.
lt is necessary to distinguish between primary and secondary Parameters.
Whereas primary Parameters (as listed in this part of ISO 12647) are
defined as having a direct bearing on the visual characteristics of the
image, secondary Parameters only influence the image indirectly by
changing the values of primary Parameters. Secondary Parameters include
- colour Separation film thickness;
image orientation (wrong-reading or right-reading);
film polarity (negative or positive);
- roughness of the emulsion surface;
- presence of colour marking or register marks.
lt is the purpose of ISO 12647-1 to list and explain the minimum set of
primary process Parameters required to uniquely define the visual
characteristics and related technical properties of a half-tone proof or
production print produced from a set of half-tone Separation films.
This part of ISO 12647 Iists suggested values or sets of values of the
primary Parameters specified in ISO 12647-1 and related technical
properties of a half-tone offset print produced from a set of half-tone
colour Separation films. Where deemed useful, secondary Parameters are
also recommended for specification.

---------------------- Page: 5 ----------------------

SIST ISO 12647-2:1997
@ ISO
ISO 12647=2:1996(E)
Other Parts of ISO 12647 will relate to other printing processes such as
.--
newspaper printing;
- gravure printing;
- Screen printing.

---------------------- Page: 6 ----------------------

SIST ISO 12647-2:1997
INTERNATIONAL STANDARD 0 ISO
ISO 12647-2:1996(E)
Process control for the manufacture of
Graphit technology -
half-tone colour Separations, proof and production prints -
Part 2:
Offset processes
1 Scope
This part of ISO 12647 specifies a number of process Parameters and their values to be applied when preparing
colour Separations for four-colour offset printing or when producing four-colour prints by one of the following
methods: heat-set web, sheet-fed or continuous forms process printing, or proofing for these processes; offset
proofing for half-tone gravure. The Parameters and values are Chosen in view of the complete process covering the
“making of the printing forme“, “proof production”, “production printing” and
process stages “colour Separation”,
“surface finishing”.
This part of ISO 12647 is
- directly applicable to proofing and printing processes that use colour Separation films as input;
- directly applicable to proofing and printing from printing surfaces produced by filmless methods and to gravure
printing as long as direct analogies to film production Systems are maintained;
- applicable to proofing with more than four process colours as long as direct analogies to four-colour printing are
maintained;
- applicable by analogy to line screens and non-periodic screens.
2 Normative references
The following Standards contain provisions which, through reference in this text, constitute provisions of this part
of ISO 12647. At the time of publication, the editions indicated were valid. All Standards are subject to revision, and
Parties to agreements based on this part of ISO 12647 are encouraged to investigate the possibility of applying the
most recent editions of the Standards indicated below. Members of IEC and ISO maintain registers of currently
valid International Standards.
ISO 5-3:1995, Photography - Density measurements - Part 3: Spectral conditions.
1) Paper and board - Measurement of specular gloss - Part 1: 75O gloss.
ISO 8254-l:- ,
ISO 12647-1: 1996, Graphit technology - Process con trol for the manufacture of half-tone colour Separations,
proo f and production prints - Part 1: Parameters and measurement methods.
1) To be published.

---------------------- Page: 7 ----------------------

SIST ISO 12647-2:1997
ISO 12647=2:1996(E) @ ISO
3 Definitions
For the purposes of this part of ISO 12647, the definition given in ISO 12647-1 and the following definitions apply.
3.1 offset (printing) plate: Plane workpiece whose surface has been coated such that an offset printing forme
tan be produced thereof.
3.2 positive-acting (offset printing) plate: Offset printing plate for use with positive polarity film.
3.3 negative-acting (offset printing) plate: Offset printing plate for use with negative polarity film.
3.4 four-colour continuous forms printing: Offset process performed on small width web-fed presses for use
with personalized mailings.
3.5 commercial/speciality printing: General purpose sheet-fed and non-magazine heat-set web offset printing.
Screen: Half-tone Screen without a regular Screen angle and without a constant
36 . non-periodic (half-tone)
en ruling.
scre
4 Requirements
The followin are arranged according to the Order set out in ISO 12647-1; they also depend on it for the
g subclauses
definition of the data and measuremen t conditions.
4.1 Colour Separation films
4.1 .l Quality
Unless otherwise specified, the core density shall be at least 2,5 above the transmission density of the clear film
(film base plus fog). The transmission density in the centre of a clear half-tone dot shall not be more than 0,l above
the corresponding value of a large clear area. The transmission density of the clear film shall not be higher than
0,15. Both measurements shall be made with a (UV) transmission densitometer whose spectral products conform
to ISO type 1 printing density as defined in ISO 5-3.
The fringe width shall not be greater than one-fortieth of the Screen width; the half-tone dot shall not be Split up
into distinct Parts. The colour Separation film quality shall be evaluated according to ISO 12647-1, annex B.
NOTES
1 The clear film density requirement is based on the understanding
- that the density range of the clear areas of all films that are to be exposed onto an offset plate, for consistent work,
should not exceed 0,lO;
that 0,05 represents the lowest commonly found value for ISO type 1 printing density.
-
In Order to minimize the impact of the use of half-tone films with clear film densities above this range, agreements between
the supplier of colour Separations and the recipient are required. Contacting or duplicating tan also be used to bring half-tone
films with dissimilar clear film densities into agreement.
2 Asa practi cal guide , a cor ‘e density of 2,5 above the clear film density will normally be
achieved if the density of Iarge solid
areas 1s more than 3,5 a bove the clear film density.
3 If a user wishes to use a blue filter for transmission density measurements it is necessary to determine, for the particular
film type and processing conditions, the correlation between densities obtained with the blue filter and those obtained with an
ISO type 1 printing density instrument; for the measurement of core density an ISO type 2 printing instrciment may be used.
2

---------------------- Page: 8 ----------------------

SIST ISO 12647-2:1997
@ ISO
ISO 12647=2:1996(E)
4.1.2 Screen ruling
For four-colour work, the Screen ruling (Screen frequency) shall be within the range 45 cm-1 to 80 cm-1. Preferred
nominal Screen rulings are:
45 cm-1 to 60 cm-1 for web offset periodical printing;
52 cm-1 to 60 cm-1 for continuous forms process printing;
60 cm-1 to 80 cm-1 for commerciaI/speciaIity printing.
NOTES
1 to 80 cm-1 the general principles specified in ISO 12647-1 remain valid but specific values
4 Outside of the range 45 cm-
may differ.
5 With computer-generated screening, the Parameters “Screen ruling” and “Screen angle” may be varied slightly in
conjuction, from one process colour to another, in Order to minimize moire Patterns.
6 For the black colour half-tone a Screen ruling may be used which is substantially finer than the nominal Screen ruling of the
chromatic colours. For example 80 cm-1 for K and 60 cm-1 for CMY.
4.1.3 Screen angle
For half-tone dots without a principal axis, the nominal differente between the Screen angles for Cyan, magenta,
and black shall be 30°, with the Screen angle of yellow separated at 15” from another colour. The Screen angle of
the dominant colour should be 45”; this value refers to the film.
For half-tone dots with a principal axis, the nominal differente between Screen angles for Cyan, magenta, and black
shall be 60°, with the Screen angle of yellow separated by 15” from another colour. The Screen angle of the
dominant colour should be 45” or 135”; these values refer to the film.
The preparation of colour Separation films for half-tone gravure printing should avoid Screen angles between 75”
and 105” with colours other than yellow.
NOTE 7 See note 5 in 4.1.2.
4.1.4 Dot shape and its relationship to tone value
Circular, Square or elliptical half-tone dot shapes shall be used. For half-tone dots with a principal axis, the first Iink-
up shall occur no Iower than at 40 % tone value and the second link-up no higher than at 60 % tone value.
4.1.5 Image size tolerante
For a set of colour Separation films in common environmental equilibrium, the lengths of the diagonals shall not
differ by more than 0,02 %.
NOTE 8 This tolerante includes image-setter repeatability and film stability.
4.1.6 Tone value sum
Unless otherwise specified, the tone value sum should be less than but shall not exceed 350 % for sheet-fed and
300 % for web-fed printing.
NOTE 9 At high levels of tone value sum press Problems such as poor trapping, back transfer and set-off due to sufficient ink
drying may be encountered.
3

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SIST ISO 12647-2:1997
ISO 1264792:1996(E)
4.1.7 Grey baiante
Unless otherwise specified, the grey balance should be given by the following tone value combinations.
Yellow
Cyan Magenta
Quarter tone 25 % 19 % 19 %
Mid tone 50 % 40 % 40 %
%
Three-quarter tone 75 % 64 % 64
4.2 Print
42.1 Visual characteristics of image components
4.2.1.1 Print Substrate colour
The print Substrate used for proofing should be identical to that of the production. If this is not possible, the
properties of the print Substrate should be a close match to that of the production in terms of colour, gloss, type of
surface (coated, uncoated, super-calendered, etc.) and mass per area. Press proofing should be carried out on the
closest match selected from five typical Paper types, whose attributes are listed in table 1. For off-press proofing
the print Substrate should be selected to conform as closely as possible to the attributes listed in table 1 of the
Paper type representing the envisaged production Paper. The type of Paper shall be stated.
Table 1
- CIELAB L*, a*, b* values, gloss, brightness and tolerantes for typical Paper types
L* 1) a* 1) b* 1)
Paper type Gloss 2) Brightnessz) Mass per area4)
1 1 %
1 % g/m*
93 0 -3 115
1: Gloss-coated, wood-free 65 85
0
92 -3 38 83 115
2: Matt-coated, wood-free
87 -1 3 70
55 70
3: Gloss-coated, web
-3
92 0 85 115
4: Uncoated, white 6
0 6 115
88 6 85
5: Uncoated, yellowish
Tolerante: +3 &2 L-2 -+5
0 5
95 70-80 80 150
Reference Papers)
1) Measurement according to ISO 12647-1 3996, 5.6: Black backing, D 50 illuminant, 2” observer, 0/45 or 45/O geometry. ’
2) Measurement according to ISO 8254-1.
3) Reflectance at 460 nm, informative only.
4) Informative only.
Paper used for ink set test (see ISO 2846-l), informative only.
5)
NOTES
IO In terms of gloss and colour, the Paper types listed in table 1 represent the corner stones of the range of print Substrates
used for the processes covered in this part of ISO 12647, with the following exceptions:
- the Paper types 1 and 2 are not typical for web-fed magazine printing except for covers;
- Paper types 3 and 5 are not typical for four-colour business forms printing.

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SIST ISO 12647-2:1997
@ ISO
ISO 12647=2:1996(E)
11 If the final product is to be surface finished, this may severely affect the print Substrate colour. See also note 17 in 4.2.1.2.
12 The L*, a”, b* values for the conditions “065” or “white backing” agree with those specified in table 1 within the
tolerantes specified there.
13 The Parameters of the reference Paper specified in ISO 2846-1 have been included in table 1, for information only, in Order
10 provide a connection to this related International Standard. Note that some values differ from ISO 2846-1 due to the black
backing.
14 The mass per area specified for Paper type 3 represents a compromise between web production Papers with typically
60 g/m* to 65 g/m* and a weil-known web proofing Paper with 90 g/m*. When measured with black backing, the differente
between similar Papers of 70 g/m* and 90 g/m* corresponds to AL,* = 0,7.
15 Although less commonly used, some web Papers in the mass per area range of type 3 Papers have b* values in the range
0 to -3.
421.2 Print Substrate gloss
The gloss of the print Substrate used for proofing should be a close match to that of the production print Substrate.
If this is not possible, press proofing may be carried out on the closest match selected from the Paper types listed
in 4.2.1.1.
NOTES
16 The gloss values of the Paper types described in 4.2.1 .l are given in table 1.
17 If the final product is to be surface finished this will severely affect the gloss. In critical cases, the result of the colour
Separation stage may be best judged by means of a proof that closely matches the gloss of the final surface-finished print
product. In Order to facilitate the matthing of the production image to the proof image at the make-ready Stage, it is a good
plan to provide the pro
...