SIST ISO 12647-2:2005

INTERNATIONAL ISO
STANDARD 12647-2
Second edition
2004-11-15
Graphic technology — Process control
for the production 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 lithographiques offset

Reference number
©
ISO 2004
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ii © ISO 2004 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 2
4 Requirements. 2
5 Test methods — Tone value and tone-value increase of a print. 12
6 Reporting of printing conditions . 12
Annex A (informative) Methods for establishing the colour of a standard ink on the paper types . 14
Annex B (informative) Dependence of the tone value increase of press prints on screen frequency. 16
Annex C (informative) Grey balance. 18
Bibliography . 19

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 part of ISO 12647 may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 12647-2 was prepared by Technical Committee ISO/TC 130, Graphic technology.
This second edition cancels and replaces the first edition (ISO 12647-2:1996), which has been extensively
revised. The revisions include the following:
a) introduction of digital data as input;
b) reduction of the tone value increase by roughly 3 %;
c) changes in the colouration of the primary and secondary solids (Table 2);
d) introduction of an additional measurement condition with a specified white backing;
e) general clean-up.
In view of the misconceptions about the use of density and grey balance values, it was decided to move this
information to an informative annex.
ISO 12647 consists of the following parts, under the general title Graphic technology — Process control for
the production of half-tone colour separations, proof and production prints:
 Part 1: Parameters and measurement methods
 Part 2: Offset lithographic processes
 Part 3: Coldset offset lithography and letterpress on newsprint
 Part 4: Publication gravure process
 Part 5: Screen printing
 Part 6: Flexographic printing

iv © ISO 2004 – All rights reserved

Introduction
Part 1 of ISO 12647 serves to provide definitions, the general principles, the general order of the material to
be covered in the subsequent parts 2 to 6, the definition of the data, the measurement conditions and the
reporting style.
This part of ISO 12647 lists values or sets of values of the primary parameters specified in ISO 12647-1 and
related technical properties of a half-tone offset lithographic print. Primary parameters include the screening
parameters, the tone value increase, the colours of the solids and the print substrate. Conformance to the
specified values in proof and production printing assure, in principle, a good visual match between specimens
produced. Exceptions from this general observation are discussed in the following paragraph.
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 often require values for
solid-tone coloration and tone-value increase that are different from those of the printing process they are
meant to simulate. This is caused by differences in phenomena such as gloss, light scatter (within the print
substrate or the colorant), metamerism and transparency. Such differences are likely for those off-press
proofing processes in which the print substrate, the colorants and the technology for applying them are
significantly different from offset press printing. In such cases the user or the supplier needs to ensure that
appropriate corrections are specified.
Another problem area is the matching of a digital off-press proof on an opaque substrate to a double-sided
print on a less-than-opaque, lightweight printing paper as used in heat-set web printing. If the proof is made
with colour management profiles based on measurements with white backing, there will be an unavoidable
difference between proof and production prints, placed on a black backing in accordance with the
specifications of this part of ISO 12647. The possible occurrence of such differences needs to be well
communicated, in advance, to the parties concerned.

INTERNATIONAL STANDARD ISO 12647-2:2004(E)

Graphic technology — Process control for the production of
half-tone colour separations, proof and production prints —
Part 2:
Offset lithographic 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 one of these
processes; or offset proofing for half-tone gravure.
The parameters and values are chosen in view of the complete process covering the process stages “colour
separation”, “film setting”, “making of the printing forme”, “proof production”, “production printing” and “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 formes produced by filmless methods as long as
direct analogies to film production systems are maintained;
 applicable to proofing and printing with more than four process colours as long as direct analogies to four-
colour printing are maintained, such as for data and screening, for print substrates and printing
parameters;
 applicable by analogy to line screens and non-periodic screens.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the reference document
(including any amendments) applies.
ISO 5-3:1995, Photography — Density measurements — Part 3: Spectral conditions
ISO 8254-1:1999, Paper and board — Measurement of specular gloss — Part 1: 75° gloss with a converging
beam, TAPPI method
ISO 12642:1996, Graphic technology — Prepress digital data exchange — Input data for characterization of
4-colour process printing
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
3 Terms and definitions
For the purposes of this document, the definitions given in ISO 12647-1 and the following apply.
3.1
positive-acting plate
〈offset printing〉 offset printing plate for use with positive-polarity film
3.2
negative-acting plate
〈offset printing〉 offset printing plate for use with negative-polarity film
3.3
four-colour continuous forms printing
offset process performed on small width web-fed presses for use with personalized mailings
3.4
commercial/speciality printing
general-purpose sheet-fed and non-magazine heat-set web offset printing
3.5
heat-set web printing
lithographic offset printing on web-type print substrates with printing ink that requires heat for drying
3.6
tone value
〈printing forme〉 percentage of surface area that appears to be receptive to printing ink
NOTE 1 With some plate types, the tone value thus defined is smaller than the percentage of surface area that is
visibly distinct from the background.
NOTE 2 Formerly known as the film printing dot area. “Dot area” is now a deprecated term.
4 Requirements
4.1 General
The following subclauses are arranged in accordance with the order set out in ISO 12647-1; they also depend
on this part for the general principles, the definition of the data, the measurement conditions and the reporting
style.
4.2 Data files, colour-separation films and printing formes
4.2.1 General
Data delivered for printing shall be in the colour formats CMYK or three-component. In all cases, digital data
files or colour separation film sets delivered for printing should be accompanied by a proof print that simulates
the intended printing condition and that conforms to 4.3. This fact shall be verifiable by measuring a well-
specified control strip or a similar control device that is printed on the proof print along with the subject.
In the case of digital data, the intended printing condition shall be indicated. Where the latter is included in the
registry of characterizations maintained by the ICC and the digital data is CMYK, the name used in the ICC
registry is usually used for identification in lieu of including an ICC output profile. If the intended printing
condition is not included in said registry, an ICC output profile shall be included. If the data are other than
CMYK, the data shall be defined colorimetrically using an ICC input profile or another mechanism and an ICC
CMYK output profile shall be included. The rendering intent to be used with the output profile shall be
communicated.
2 © ISO 2004 – All rights reserved

4.2.2 Film or printing forme quality
In order to permit the reproduction of at least 100 tone-value steps, the resolution of the image setter or plate
setter should be set accordingly.
−1
EXAMPLE 1 If, for a screen employing single half-tone cell modulation, the intended nominal screen ruling is 70 cm ,
−1
the resolution of the image setter or the plate setter should not be smaller than 700 cm (1 800 dpi). For a screen with
super-cell technology, it is possible to set the resolution to a smaller value.
Unless otherwise specified, the core density of colour-separation films 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. 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.
NOTE 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 the same plate are not expected to exceed 0,10. Not
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