ISO 12647-3:2005

Graphic technology — Process control for the production of half-tone colour separations, proofs and production prints — Part 3: Coldset offset lithography on newsprint

ISO 12647-3:2005 specifies a number of process parameters and their values to be applied when preparing colour separations for newspaper single or four-colour printing and proofing. The parameters and values are chosen in consideration of the complete process, covering the process stages: colour separation, film setting, making of the printing forme, proof production and production printing. ISO 12647-3:2005 is applicable: to coldset offset proof and production printing and off-press proof printing processes on newsprint that use colour separation films rather than digital data; by analogy to press printing from printing surfaces produced by direct imaging methods and the corresponding proof printing processes.

Technologie graphique — Contrôle du processus de confection de sélections couleurs tramées, d'épreuves et de tirages — Partie 3: Impression offset sans sécheur sur papier journal

Grafična tehnologija – Vodenje procesa izdelave rastriranih barvnih izvlečkov ter preskusnih in proizvodnih odtisov – 3. del: Procesi v časopisnem ofsetnem tisku na rotacijah s hladnim sušenjem

General Information

• Status: Withdrawn
• Publication Date: 27-Sep-2005
• Withdrawal Date: 27-Sep-2005
• ICS: 37.100.01 - Graphic technology in general
• Technical Committee: ISO/TC 130 - Graphic technology
• Drafting Committee: ISO/TC 130/WG 3 - Process control and related metrology
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 12-Dec-2013
• Ref Project: SIST ISO 12647-3:2006 - Graphic technology -- Process control for the production of half-tone colour separations, proofs and production prints -- Part 3: Coldset offset lithography on newsprint

Relations

• Revised: ISO 12647-3:2013 - Graphic technology — Process control for the production of half-tone colour separations, proofs and production prints — Part 3: Coldset offset lithography on newsprint
• Effective Date: 04-Dec-2010
• Revised: SIST ISO 12647-3:2002 - Graphic technology -- Process control for the manufacture of half-tone colour separations, proofs and production prints -- Part 3: Coldset offset lithography and letterpress on newsprint
• Effective Date: 12-May-2008
• Revises: ISO 12647-3:1998 - Graphic technology — Process control for the manufacture of half-tone colour separations, proofs and production prints — Part 3: Coldset offset lithography and letterpress on newsprint
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 12647-3
Second edition
2005-10-01

Graphic technology — Process control
for the production of half-tone colour
separations, proofs and production
prints —
Part 3:
Coldset offset lithography on newsprint
Technologie graphique — Contrôle du processus de confection de
sélections couleurs tramées, d'épreuves et de tirages —
Partie 3: Impression offset sans sécheur sur papier journal




Reference number
ISO 12647-3:2005(E)
©
ISO 2005

---------------------- Page: 1 ----------------------
ISO 12647-3:2005(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.


©  ISO 2005
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland

ii © ISO 2005 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 12647-3:2005(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 Data file, colour separation films and printing formes . 2
4.3 Proof or production print . 4
4.4 Additional requirements for single-colour reproduction and printing. 10
5 Test method: tone value and tone value increase of a print. 10
Annex A (informative) Tolerances for the secondary colour solids . 11
Annex B (informative) Densities of ink set colours . 12
Annex C (informative) Characterization data for 26 % and 30 % tone value increase . 13
Annex D (informative) Grey balance. 14
Bibliography . 15

© ISO 2005 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 12647-3:2005(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 12647-3 was prepared by Technical Committee ISO/TC 130, Graphic technology.
This second edition cancels and replaces the first edition (ISO 12467-3:1998) which has been technically
revised, in particular the tone value increase values specified, as borne out by the print characteristic curves
of Figure 3. Parameters of all process steps have to be adjusted to achieve these curves; they apply
irrespective of whether a positive or a negative acting plate making process is used. The reference to
letterpress has been removed completely. Some solid colour CIELAB values have been changed slightly in
response to demands from the field.
ISO 12647 consists of the following parts, under the general title Graphic technology — Process control for
the production of half-tone colour separations, proofs and production prints:
⎯ Part 1: Parameters and measurement methods
⎯ Part 2: Offset lithographic processes
⎯ Part 3: Coldset offset lithography on newsprint
⎯ Part 4: Publication gravure printing
⎯ Part 5: Screen printing
⎯ Part 6: Flexographic printing
iv © ISO 2005 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 12647-3:2005(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. 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 whose purpose is to simulate the visual characteristics of the finished print
product as closely as possible.
For more information on the technical background refer to ISO 12647-1.
It is the purpose of this part of ISO 12647 to list and explain the minimum set of process parameters required
to uniquely define the visual characteristics and related technical properties of a half-tone proof or production
print produced by coldset offset lithography on newsprint, or half-tone proof designed to simulate this, from a
set of half-tone separation films.
It is a further purpose of this part of ISO 12647 to list values or sets of values of the primary parameters
specified in ISO 12647-1 and related technical properties of a half-tone newspaper print or proof produced
from a set of half-tone colour separation films. Where deemed useful, secondary parameters are also
recommended for specification.
Since non-periodic screening and direct-to-plate techniques are common practice within newspaper printing,
information on some of the pertinent parameters has been included.

© ISO 2005 – All rights reserved v

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 12647-3:2005(E)

Graphic technology — Process control for the production of
half-tone colour separations, proofs and production prints —
Part 3:
Coldset offset lithography on newsprint
1 Scope
This part of ISO 12647 specifies a number of process parameters and their values to be applied when
preparing colour separations for newspaper single or four-colour printing and proofing. The parameters and
values are chosen in consideration of the complete process, covering the process stages: “colour separation”,
“film setting”, “making of the printing forme”, “proof production” and “production printing”.
This part of ISO 12647 is applicable:
⎯ to coldset offset proof and production printing and off-press proof printing processes on newsprint that
use colour separation films rather than digital data;
⎯ by analogy to press printing from printing surfaces produced by direct imaging methods and the
corresponding proof printing processes.
⎯ It is not applicable:
⎯ to line screens and non-periodic screens although certain parameters given can be applied by analogy. In
particular, the tone value increases specified, apply directly because they refer to control patches that
contain periodic screen half-tones;
⎯ to flexo and letterpress production printing although a number of parameters can be applied by analogy.
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 5-3, Photography — Density measurements — Part 3: Spectral conditions
ISO 8254-1, Paper and board — Measurement of specular gloss — Part 1: 75 degree gloss with a converging
beam, TAPPI method
ISO 12647-1:2004, Graphic technology — Process control for the production of half-tone colour separations,
proof and production prints — Part 1: Parameters and measurement methods
ISO 15930-4, Graphic technology — Prepress digital data exchange using PDF — Part 4: Complete exchange
of CMYK and spot colour printing data using PDF 1.4 (PDF/X-1a)
ISO 15930-6, Graphic technology — Prepress digital data exchange using PDF — Part 6: Complete exchange
of printing data suitable for colour-managed workflows using PDF 1.4 (PDF/X-3)
© ISO 2005 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO 12647-3:2005(E)
3 Terms and definitions
For the purposes of this document the definitions given in ISO 12647-1 and the following apply.
3.1
coldset offset lithography
method of offset lithographic printing where the inks set ("dry") primarily by absorption into the print substrate
4 Requirements
4.1 General
The following subclauses are arranged according to the order set out in ISO 12647-1. They also depend on it
for the definition of the parameters and test methods.
If data files or colour separation film sets are supplied for printing they should be accompanied by a proof print
that simulates the intended production printing condition to a sufficient degree. This fact shall be verifiable by
measuring a well-known control strip or a similar control device that is printed on the proof print along with the
subject.
4.2 Data file, colour separation films and printing formes
4.2.1 General
Electronic data should be delivered as PDF/X-1 or PDF/X-3 data files as defined in ISO 15930-4 or
ISO 15930-6. Where film is supplied, the intended receiver of the film shall specify the tone value curve for
which the film shall be prepared.
4.2.2 Film or printing forme quality
The tone values for film and printing formes shall be adjusted such that, for all primary colours, the tone value
increase from data to paper conforms to one of the two curves specified in 4.3.4.1. Within an ink set, the
printed characteristics of all the primary printing ink colours shall conform to the same tone value curve.
NOTE 1 Data sender and receiver need to agree on which of the two curves specified in Table 5 and shown in Figure 3
will be used. The choice of the appropriate curve for common use is generally made by national or international trade
associations.
NOTE 2 Methods for tone value adjustments include setting of the RIP look-up table, choosing a suitable blanket type,
suitable setting of the plate to blanket pressure and adjustment of the ink rheology.
EXAMPLE 1 Conventional plate making with negative film produces a tone value increase of 33 % in the mid tone. In
order to achieve 26 %, the RIP look-up table was adjusted by − 4 % and the choice of a different ink generated a 3 %
lower tone value increase. These two adjustments lowered the tone value increase to 26 %. If 30 % is to be achieved, less
adjustments are necessary to reach the correct tone value increase.
EXAMPLE 2 With a given CTP system the tone value increase was found to be 22 %. An increased blanket to plate
pressure yielded + 2 %, the remaining + 2 % were introduced at the RIP look-up table; 26 % tone value increase was
achieved.
−1
The resolution of the film or plate setter should be set to 500 cm and shall not be set to a lower value than
−1
472 cm in order to assure a sufficient number of generated tone value steps.
The deviation of tone values over the complete printing forme shall not exceed ± 2 %. The deviation range of
the measuring device (densitometer or camera-based device) shall be added to this value.
2 © ISO 2005 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 12647-3:2005(E)
Unless otherwise specified, the core density of a colour separation film 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 0,1 above the corresponding value of a large clear area. The transmission
density of the clear film shall not be higher than 0,15.
The fringe width of a colour separation film shall not be greater than 6 µm.
The colour separation film quality should be evaluated according to Annex B of ISO 12647-1:2004.
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; for the evaluation of core properties, type 2 printing density
may be used.
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 on to an offset plate, for consistent work, should not exceed 0,10.
NOTE 3 As a practical guide, a core density of 2,5 above the clear film density will normally be achieved if the density
of large solid areas is more than 3,5 above the clear film density.
NOTE 4 With non-periodic screens, a fringe width of not more than 4 µm is reported to give reliable results.
4.2.3 Screen frequency
−1
For four-colour work, the screen frequency should be (40 ± 2) cm . Within the same copy of a newspaper,
the screen ruling shall be the same for colour and black-and-white printing. If, as an exception, other screen
rulings are used, the tone value increase shall be adjusted such that it agrees with Table 5 and Figure 3.
NOTE 1 With computer-generated screening, the parameters screen ruling and screen angle can be varied slightly in
conjunction, from one process colour to another, in order to minimize moiré patterns.
NOTE 2 With non-periodic screens, reliable results are obtained if the minimum dimension of the image elements is
40 µm.
4.2.4 Screen angle
For half-tone dots without a principal axis, the nominal difference between the screen angles for cyan (C),
magenta (M) and black (K) shall be 30°, with the screen angle of yellow separated at 15° from any other
colour. The screen angle of the dominant colour should be 45°.
For half-tone dots with a principal axis, the nominal difference between screen angles for cyan, magenta and
black shall be 60°, with the screen angle of yellow at 0° and 15° off from the next screen angle. The screen
angle of the dominant colour should be 135°.
...

SLOVENSKI STANDARD
SIST ISO 12647-3:2006
01-september-2006
*UDILþQDWHKQRORJLMD±9RGHQMHSURFHVDL]GHODYHUDVWULUDQLKEDUYQLKL]YOHþNRYWHU
SUHVNXVQLKLQSURL]YRGQLKRGWLVRY±GHO3URFHVLYþDVRSLVQHPRIVHWQHPWLVNX
QDURWDFLMDKVKODGQLPVXãHQMHP
Graphic technology -- Process control for the production of half-tone colour separations,
proofs and production prints -- Part 3: Coldset offset lithography on newsprint
Technologie graphique -- Contrôle du processus de confection de sélections couleurs
tramées, d'épreuves et de tirages -- Partie 3: Impression offset sans sécheur sur papier
journal
Ta slovenski standard je istoveten z: ISO 12647-3:2005
ICS:
37.100.01 *UDILþQDWHKQRORJLMDQD Graphic technology in
VSORãQR general
SIST ISO 12647-3:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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

SIST ISO 12647-3:2006

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

SIST ISO 12647-3:2006


INTERNATIONAL ISO
STANDARD 12647-3
Second edition
2005-10-01

Graphic technology — Process control
for the production of half-tone colour
separations, proofs and production
prints —
Part 3:
Coldset offset lithography on newsprint
Technologie graphique — Contrôle du processus de confection de
sélections couleurs tramées, d'épreuves et de tirages —
Partie 3: Impression offset sans sécheur sur papier journal




Reference number
ISO 12647-3:2005(E)
©
ISO 2005

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

SIST ISO 12647-3:2006
ISO 12647-3:2005(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.


©  ISO 2005
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland

ii © ISO 2005 – All rights reserved

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

SIST ISO 12647-3:2006
ISO 12647-3:2005(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 Data file, colour separation films and printing formes . 2
4.3 Proof or production print . 4
4.4 Additional requirements for single-colour reproduction and printing. 10
5 Test method: tone value and tone value increase of a print. 10
Annex A (informative) Tolerances for the secondary colour solids . 11
Annex B (informative) Densities of ink set colours . 12
Annex C (informative) Characterization data for 26 % and 30 % tone value increase . 13
Annex D (informative) Grey balance. 14
Bibliography . 15

© ISO 2005 – All rights reserved iii

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

SIST ISO 12647-3:2006
ISO 12647-3:2005(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 12647-3 was prepared by Technical Committee ISO/TC 130, Graphic technology.
This second edition cancels and replaces the first edition (ISO 12467-3:1998) which has been technically
revised, in particular the tone value increase values specified, as borne out by the print characteristic curves
of Figure 3. Parameters of all process steps have to be adjusted to achieve these curves; they apply
irrespective of whether a positive or a negative acting plate making process is used. The reference to
letterpress has been removed completely. Some solid colour CIELAB values have been changed slightly in
response to demands from the field.
ISO 12647 consists of the following parts, under the general title Graphic technology — Process control for
the production of half-tone colour separations, proofs and production prints:
⎯ Part 1: Parameters and measurement methods
⎯ Part 2: Offset lithographic processes
⎯ Part 3: Coldset offset lithography on newsprint
⎯ Part 4: Publication gravure printing
⎯ Part 5: Screen printing
⎯ Part 6: Flexographic printing
iv © ISO 2005 – All rights reserved

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

SIST ISO 12647-3:2006
ISO 12647-3:2005(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. 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 whose purpose is to simulate the visual characteristics of the finished print
product as closely as possible.
For more information on the technical background refer to ISO 12647-1.
It is the purpose of this part of ISO 12647 to list and explain the minimum set of process parameters required
to uniquely define the visual characteristics and related technical properties of a half-tone proof or production
print produced by coldset offset lithography on newsprint, or half-tone proof designed to simulate this, from a
set of half-tone separation films.
It is a further purpose of this part of ISO 12647 to list values or sets of values of the primary parameters
specified in ISO 12647-1 and related technical properties of a half-tone newspaper print or proof produced
from a set of half-tone colour separation films. Where deemed useful, secondary parameters are also
recommended for specification.
Since non-periodic screening and direct-to-plate techniques are common practice within newspaper printing,
information on some of the pertinent parameters has been included.

© ISO 2005 – All rights reserved v

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

SIST ISO 12647-3:2006

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

SIST ISO 12647-3:2006
INTERNATIONAL STANDARD ISO 12647-3:2005(E)

Graphic technology — Process control for the production of
half-tone colour separations, proofs and production prints —
Part 3:
Coldset offset lithography on newsprint
1 Scope
This part of ISO 12647 specifies a number of process parameters and their values to be applied when
preparing colour separations for newspaper single or four-colour printing and proofing. The parameters and
values are chosen in consideration of the complete process, covering the process stages: “colour separation”,
“film setting”, “making of the printing forme”, “proof production” and “production printing”.
This part of ISO 12647 is applicable:
⎯ to coldset offset proof and production printing and off-press proof printing processes on newsprint that
use colour separation films rather than digital data;
⎯ by analogy to press printing from printing surfaces produced by direct imaging methods and the
corresponding proof printing processes.
⎯ It is not applicable:
⎯ to line screens and non-periodic screens although certain parameters given can be applied by analogy. In
particular, the tone value increases specified, apply directly because they refer to control patches that
contain periodic screen half-tones;
⎯ to flexo and letterpress production printing although a number of parameters can be applied by analogy.
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 5-3, Photography — Density measurements — Part 3: Spectral conditions
ISO 8254-1, Paper and board — Measurement of specular gloss — Part 1: 75 degree gloss with a converging
beam, TAPPI method
ISO 12647-1:2004, Graphic technology — Process control for the production of half-tone colour separations,
proof and production prints — Part 1: Parameters and measurement methods
ISO 15930-4, Graphic technology — Prepress digital data exchange using PDF — Part 4: Complete exchange
of CMYK and spot colour printing data using PDF 1.4 (PDF/X-1a)
ISO 15930-6, Graphic technology — Prepress digital data exchange using PDF — Part 6: Complete exchange
of printing data suitable for colour-managed workflows using PDF 1.4 (PDF/X-3)
© ISO 2005 – All rights reserved 1

---------------------- Page: 9 ----------------------

SIST ISO 12647-3:2006
ISO 12647-3:2005(E)
3 Terms and definitions
For the purposes of this document the definitions given in ISO 12647-1 and the following apply.
3.1
coldset offset lithography
method of offset lithographic printing where the inks set ("dry") primarily by absorption into the print substrate
4 Requirements
4.1 General
The following subclauses are arranged according to the order set out in ISO 12647-1. They also depend on it
for the definition of the parameters and test methods.
If data files or colour separation film sets are supplied for printing they should be accompanied by a proof print
that simulates the intended production printing condition to a sufficient degree. This fact shall be verifiable by
measuring a well-known control strip or a similar control device that is printed on the proof print along with the
subject.
4.2 Data file, colour separation films and printing formes
4.2.1 General
Electronic data should be delivered as PDF/X-1 or PDF/X-3 data files as defined in ISO 15930-4 or
ISO 15930-6. Where film is supplied, the intended receiver of the film shall specify the tone value curve for
which the film shall be prepared.
4.2.2 Film or printing forme quality
The tone values for film and printing formes shall be adjusted such that, for all primary colours, the tone value
increase from data to paper conforms to one of the two curves specified in 4.3.4.1. Within an ink set, the
printed characteristics of all the primary printing ink colours shall conform to the same tone value curve.
NOTE 1 Data sender and receiver need to agree on which of the two curves specified in Table 5 and shown in Figure 3
will be used. The choice of the appropriate curve for common use is generally made by national or international trade
associations.
NOTE 2 Methods for tone value adjustments include setting of the RIP look-up table, choosing a suitable blanket type,
suitable setting of the plate to blanket pressure and adjustment of the ink rheology.
EXAMPLE 1 Conventional plate making with negative film produces a tone value increase of 33 % in the mid tone. In
order to achieve 26 %, the RIP look-up table was adjusted by − 4 % and the choice of a different ink generated a 3 %
lower tone value increase. These two adjustments lowered the tone value increase to 26 %. If 30 % is to be achieved, less
adjustments are necessary to reach the correct tone value increase.
EXAMPLE 2 With a given CTP system the tone value increase was found to be 22 %. An increased blanket to plate
pressure yielded + 2 %, the remaining + 2 % were introduced at the RIP look-up table; 26 % tone value increase was
achieved.
−1
The resolution of the film or plate setter should be set to 500 cm and shall not be set to a lower value than
−1
472 cm in order to assure a sufficient number of generated tone value steps.
The deviation of tone values over the complete printing forme shall not exceed ± 2 %. The deviation range of
the measuring device (densitometer or camera-based device) shall be added to this value.
2 © ISO 2005 – All rights reserved

---------------------- Page: 10 ----------------------

SIST ISO 12647-3:2006
ISO 12647-3:2005(E)
Unless otherwise specified, the core density of a colour separation film 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 0,1 above the corresponding value of a large clear area. The transmission
density of the clear film shall not be higher than 0,15.
The fringe width of a colour separation film shall not be greater than 6 µm.
The colour separation film quality should be evaluated according to Annex B of ISO 12647-1:2004.
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; for the evaluation of core properties, type 2 printing density
may be used.
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 on to an offset plate, for consistent work, should not exceed 0,10.
NOTE 3 As a practical guide, a core density of 2,5 above the clear film density will normally be achieved if the density
of large solid areas is more than 3,5 above the clear film density.
NOTE 4 With non-periodic screens, a fringe width of not more than 4 µm is reported to give reliable results.
4.2.3 Screen frequency
−1
For four-colour work, the screen frequency should be (40 ± 2) cm . Within the same copy of a newspaper,
the screen ruling shall be the same for colour and black-and-white printing. If, as an exception, other screen
rulings are used, the tone value increase shall be adjusted such that it agrees with Table 5 and Figure 3.
NOTE 1 With computer-generated screening, the parameters screen ruling and screen angle can be varied slightly in
conjunction, from one process colour to another, in order to minimize moiré patterns.
NOTE 2 With non-periodic screens, reliable results are obtained if the minimum dimension of the image eleme
...