Graphic technology — Process control for the production of half-tone colour separations, proof and production prints — Part 1: Parameters and measurement methods

ISO 12647-1:2004 specify parameters that define printing conditions for the various processes used in the graphic arts industry. Practitioners wishing to work to common goals may use the values of the parameters specified in the exchange of data to characterize the intended printing condition and/or for the process control of printing. ISO 12647-1:2004 defines vocabulary and establishes a minimum set of process parameters that uniquely determine a printed four-colour half-tone image (which are also referenced from other parts of ISO 12647). The parameters were selected based on the following process stages "colour separation", "making of the printing forme", "proofing", "production printing" and "surface finishing". These are directly applicable to proofing and printing processes that use colour separation films as input; is directly applicable to proofing and printing from printing surfaces produced by filmless methods as long as direct analogies to film production systems are maintained; is 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; is applicable to line screens and, where relevant, to those that do not have regular screen angles or regular screen rulings.

Technologie graphique — Maîtrise de procédé pour la production des séparations de couleur en ton tramé, des épreuves et des tirages en production — Partie 1: Paramètres et méthodes de mesurage

Grafična tehnologija - Vodenje procesa izdelave rastriranih barvnih izvlečkov, preskusnih in proizvodnih odtisov - 1. del: Parametri in merilne metode

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Status
Withdrawn
Publication Date
20-Jul-2004
Withdrawal Date
20-Jul-2004
Current Stage
9599 - Withdrawal of International Standard
Start Date
12-Dec-2013
Completion Date
12-Dec-2013

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INTERNATIONAL ISO
STANDARD 12647-1
Second edition
2004-08-01
Graphic technology — Process control
for the production of half-tone colour
separations, proof and production
prints —
Part 1:
Parameters and measurement methods
Technologie graphique — Maîtrise de procédé pour la production des
séparations de couleur en ton tramé, des épreuves et des tirages en
production —
Partie 1: Paramètres et méthodes de mesurage
Reference number
ISO 12647-1:2004(E)
ISO 2004
---------------------- Page: 1 ----------------------
ISO 12647-1:2004(E)
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© ISO 2004

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ii © ISO 2004 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 12647-1:2004(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

1 Scope...................................................................................................................................................... 1

2 Normative references........................................................................................................................... 1

3 Terms and definitions........................................................................................................................... 2

4 Requirements........................................................................................................................................ 9

4.1 General................................................................................................................................................... 9

4.2 Data file, colour separation films and printing formes ..................................................................... 9

4.3 Proof or production print ................................................................................................................... 11

5 Test methods....................................................................................................................................... 13

5.1 Screen angles...................................................................................................................................... 13

5.2 Tone value on a colour-separation film or of a data file ................................................................. 14

5.3 Tone value on the print....................................................................................................................... 14

5.4 Tone value increase on the print....................................................................................................... 15

5.5 Gloss.................................................................................................................................................... 15

5.6 Spectral measurement, computation of CIELAB colour co-ordinates and CIELAB colour

differences ........................................................................................................................................... 15

Annex A (normative) Reporting ...................................................................................................................... 17

Annex B (informative) Determination of quality parameters of half-tone dots on a colour

separation film..................................................................................................................................... 19

Bibliography ..................................................................................................................................................... 21

© ISO 2004 – All rights reserved iii
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ISO 12647-1:2004(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 12647-1 was prepared by Technical Committee ISO/TC 130, Graphic technology.

This second edition, which has been extensively revised by the introduction of digital data as input, the

addition of several definitions and a general clean up, cancels and replaces the first edition

(ISO 12647-1:1996).

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 printing
 Part 5: Screen printing
 Part 6: Flexographic printing

Part 7: Processes using digital printing or reproductions made on various traditional printing processes from

digital files is in preparation.
iv © ISO 2004 – All rights reserved
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ISO 12647-1:2004(E)
Introduction

When producing a colour reproduction, it is important that the persons responsible for colour separation,

proofing and printing operations have previously agreed on a minimum set of parameters that uniquely defines

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 analogue or digital 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.

It is the purpose of this part of ISO 12647 to list and explain the minimum set of primary process parameters

(see below) required to uniquely define the visual characteristics and related technical properties of a proof or

production print produced directly from digital data or from a set of half-tone separation films. Other parts of

ISO 12647 define specific values for these parameters that are appropriate for specific processes (such as

lithography, gravure, flexography, screen printing). For some processes certain parameters are more

significant than others and may be specified as mandatory while the remainder are optional. However, in this

part of ISO 12647, all parameters are treated equally.

Primary parameters are defined here as having a direct bearing on the visual characteristics of the image;

secondary parameters are defined as those which may 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 film emulsion surface;
 presence of colour marking or register marks;
 printing sequence.

Where necessary for specific process applications, secondary parameters and further related details may be

specified in addition to primary parameters, but they are not included in this part of ISO 12647 except in the

definitions.

During the process of colour separation for multi-colour printing, a digital data set comprising CMYK tone

values ready for printing is normally produced from digital data that relate to a multi-coloured continuous-tone

original. This usually consists of a photographic transparency or a reflection copy print, although any

multicoloured graphic in analogue or digital form may be used as input.

The majority of printing processes covered by ISO 12647 requires continuous-tone images to be broken up

into half-tone screens before they can be put on a printing forme. However, there are new processes like

inkjet that do not require screening. For these processes, this part of ISO 12647 may be equally applied, with

the exception of the specifications for screen width, screen angle, half-tone dot shape and, of course, film

quality. It should be noted that a number of off-press proofing systems produce images without recourse to

half-toning. In this case, the proof cannot be used to predict artefacts like moiré that may be caused by

interferences between periodic structures of the image and half-tones used in production printing.

The process of colour separation does not provide a unique transformation of the colour values of the original

into those of the production print. For every distinguishable spot of the original, the colour (characterizable by

three colorimetric values, e.g. X, Y, Z or L*, a*, b* or hue, saturation and lightness) has to be separated into

tone values for four or more process colours. However, in most cases, the density range (and, hence, the

© ISO 2004 – All rights reserved v
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ISO 12647-1:2004(E)

colour gamut) of the original is wider than that achievable in printing. As a result, the classical colour

separation process requires some degree of interpretation of the original by the operator and the resultant

transformation may differ from one original to another. With ICC colour management, the mentioned ambiguity

is reduced to vendor-specific options for the user; within a given option set the results are reproducible. A

further source of variation is the degree and manner by which the achromatic component of a colour is

generated with black ink rather than by a suitable mix of the chromatic inks. Here again, a number of options

exist, which may to some degree be vendor-specific.

Whatever freedom exists for the colour separation process, it is important that it take account of the values of

the process parameters of the printing condition to be used for production. This is because the process steps

that follow colour separation, namely output on film (if required), proofing (on- or off-press), the production of

the printing forme (if required), production printing and print surface finishing, are normally carried out with a

rigid set of process parameters which include
 the properties of the print substrate;
 the optical properties of solid prints of the process inks;
 the tone value increase curve.

Maintaining consistent values for the parameters at all steps in the process is important to ensure predictable

reproduction. Any unforeseen variation of these values is usually to the detriment of the visual characteristics

of the image.

The technical background discussed so far shows that the processes of colour separation and proofing

require prior knowledge of the values of the process parameters encountered in production printing. It is

virtually impossible to print all jobs with the same set of process parameters, irrespective of the type of printing

press or digital printing unit, printing forme, printing ink, print substrate, or surface finishing used. Therefore,

there has to be an efficient information exchange between the pre-press service provider, the proof printer and

the production printer which defines the specific parameters for that job.

To facilitate the information interchange, this part of ISO 12647 defines a complete set of parameters whose

values should be specified as a minimum when a pre-press job consisting of a digital file or a set of colour-

separation films, both with accompanying proof print, is being ordered. Specific values for each parameter are

assigned in other parts of ISO 12647; this part is only concerned with definitions, principal requirements,

reporting and test methods.

Because the proof print is the principal means of communication between pre-press, print-buyer and printer, it

is important that

 the proof print be made using the best achievable simulation of the intended printing condition, and

 production printing attempt to match the visual characteristics of the approved proof print.

One of the major variations between and within printing processes is between tone-value-increase curves

(formerly “dot gain curves”), examples of which are shown schematically in Figure 1. One such curve, with

appropriate tolerances, may be specified for every process colour, for each specific combination of print

substrate type and printing process.
vi © ISO 2004 – All rights reserved
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INTERNATIONAL STANDARD ISO 12647-1:2004(E)
Graphic technology — Process control for the production of
half-tone colour separations, proof and production prints —
Part 1:
Parameters and measurement methods
1 Scope

This and other parts of ISO 12647 specify parameters that define printing conditions for the various processes

used in the graphic arts industry. Practitioners wishing to work to common goals may use the values of the

parameters specified in the exchange of data to characterize the intended printing condition and/or for the

process control of printing.
This part of ISO 12647

 defines vocabulary and establishes a minimum set of process parameters that uniquely determine a

printed four-colour half-tone image (which are also referenced from other parts of ISO 12647). The

parameters were selected based on the following process stages “colour separation”, “making of the

printing forme”, “proofing”, “production printing” and “surface finishing”. These are directly applicable to

proofing and printing processes that use colour separation films as input;

 is directly applicable to proofing and printing from printing surfaces produced by filmless methods as long

as direct analogies to film production systems are maintained;

 is 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;

 is applicable to line screens and, where relevant, to those that do not have regular screen angles or

regular screen rulings.
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 5-2, Photography — Density measurements — Part 2: Geometric conditions for transmission density

ISO 5-3, Photography — Density measurement — Part 3: Spectral conditions

ISO 5-4, Photography — Density measurements — Part 4: Geometric conditions for reflection density

ISO 13655, Graphic technology — Spectral measurement and colorimetric computation for graphic arts

images
© ISO 2004 – All rights reserved 1
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ISO 12647-1:2004(E)
3 Terms and definitions

For the purpose of all parts of ISO 12647 the following definitions apply, they are given in alphabetical order.

For convenience, some definitions are included in anticipation of their use in subsequent parts of ISO 12647.

NOTE For quantities, the preferred unit is given together with the definition. By definition, the unit of the so-called

dimensionless quantities is 1.
3.1
achromatic colour
perceived colour devoid of hue, in the perceptual sense
[3]
[adapted from 845-02-26 of CIE 17.4 ]

NOTE 1 The colour names white, grey and black are commonly used or, for transmitting objects, colourless and neutral.

NOTE 2 In printing practice, achromatic colours can be produced either by a single ink or three chromatic inks suitably

balanced.
3.2
axis of a screen

one of the two directions in which the half-tone pattern shows the highest number of image elements, such as

dots or lines, per length
3.3
chromatic colour
perceived colour possessing hue, in the perceptual sense
[3]
[adapted from 845-02-27 of CIE 17.4 ]
NOTE The process inks cyan, magenta and yellow are the chromatic colour inks.
3.4
CIELAB colour difference
CIE 1976 L*, a*, b* colour difference

difference between two colour stimuli defined as the Euclidean distance between the points representing them

in L*, a*, b* space
[3]
[adapted from 845-03-55 of CIE 17.4 ]
NOTE The unit is 1.
3.5
CIELAB colour space
CIE 1976 L* a* b* colour space

three-dimensional, approximately uniform colour space produced by plotting L*, a*, b* in rectangular co-

ordinates
[3]
[adapted from 845-03-56 of CIE 17.4 ]
3.6
colorimeter

instrument for measuring colorimetric quantities, such as the tristimulus values of a colour stimulus

[3]
[845-05-18 of CIE 17.4 ]

NOTE A tristimulus colorimeter achieves this by the analogue integration of the spectral product of object reflectance

or transmittance factor, illuminant and filters which are defined by standard illuminant and the standard observer functions.

A spectrocolorimeter achieves this by calculation from the spectral data.
2 © ISO 2004 – All rights reserved
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ISO 12647-1:2004(E)
3.7
colour-separation film

one of a set of black-and-white half-tone films for process printing that pertains to one process colour

NOTE There are usually four colour-separation films in a set.
3.8
control patch
area produced for control or measurement purposes
3.9
control strip
one-dimensional array of control patches
3.10
core density

〈half-tone film〉 transmittance density in the centre of an isolated opaque image element such as a half-tone

dot or line
NOTE The unit is 1.
3.11
deviation tolerance

permissible difference between the OK print (3.26) from a production run and the reference value

3.12
film emulsion orientation

orientation of a colour separation film relative to the observer with respect to the emulsion side

NOTE Normal orientation is emulsion up, i.e. towards the observer.
3.13
fringe width

〈isolated opaque image element〉 average distance between the density contour lines corresponding to 10 %

and 90 % of the minimum core density specified for the printing process under consideration

NOTE Fringe width is expressed in units of micrometres.
3.14
grey balance

set of tone values for cyan, magenta and yellow on the colour-separation films (3.7) that appears as an

achromatic colour under specified viewing conditions if printed under specified printing conditions

NOTE There are two practical definitions for grey: “a colour having the same CIELAB a* and b* values as the print

substrate” and “a colour that has the same CIELAB a* and b* values as a half-tone tint of similar L* value printed with

black ink”.
3.15
half-tone film

film for use with a half-tone printing process showing image elements such as dots or lines

3.16
hard-dot film

colour-separation film with half-tone dots that reproduce reliably in film duplication and production of the

printing forme
© ISO 2004 – All rights reserved 3
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ISO 12647-1:2004(E)
3.17
ICC colour management

communication, by means of an ICC profile, of the associated data, required for unambiguous interpretation of

colour content data and application of colour data conversions using this profile, as required, to produce the

intended reproductions

NOTE 1 This definition is adapted from that in ISO 15076, which is under preparation.

NOTE 2 Colour content can consist of text, line art, graphics, and pictorial images, in raster or vector from, all of which

can be colour managed.

NOTE 3 Colour management considers the characteristics of input and output devices in determining colour data

conversions for these devices.
[adapted from ISO 15076-1]
3.18
International Color Consortium
ICC

industry body responsible for the ICC profile specification and colour management architecture

3.19
ICC profile
set of colorimetric transforms prepared in accordance with ICC.1
[Reference 4]
3.20
image orientation

orientation of text and images, designated right-reading if text appears as it is intended to be read and images

are in the orientation intended for viewing by the end user and wrong-reading for the opposite

NOTE 1 The film-emulsion orientation requires specification as well: state “emulsion up” or “emulsion down”. “Emulsion

up” is usually assumed if there is no film-emulsion orientation statement.

NOTE 2 A typical reference is “wrong-reading emulsion up” which is equivalent to “right-reading emulsion down”.

3.21
mid-tone spread
quantity defined by the equation
S = max[(A −A ),(A −A ),(A −A )] − min[(A −A ),(A −A ),(A −A )]
c c0 m m0 y y0 c c0 m m0 y y0
where
A is the measured tone value of the cyan process colour image;
A is the specified tone value of the cyan process colour image;
A is the measured tone value of the magenta process colour image;
A is the specified tone value of the magenta process colour image;
A is the measured tone value of the yellow process colour image;
A is the specified tone value of the yellow process colour image.

EXAMPLE For measured values A = 22, A 17 and A = 20 and specified values A = 20, A = 20 and

c m y c0 m0
A = 18):
S = max[(22−20),(17−20),(20−18)] − min[(22−20),(17−20),(20−18)] = 2−(−3) = 5
4 © ISO 2004 – All rights reserved
---------------------- Page: 10 ----------------------
ISO 12647-1:2004(E)
3.22
moiré pattern

unwanted periodic structure produced by interference between two or more two-dimensional periodic

structures
3.23
negative film polarity

property of a colour separation film, whose clear and solid areas on the film correspond to solid and unprinted

areas on the print, respectively
3.24
non-periodic half-tone screen
half-tone screen without a regular half-tone dot pattern
3.25
off-press proof print

print produced by a method other than press printing whose purpose is to show the results of the colour

separation process in a way that closely simulates the results on a production press

NOTE Also known as artificial or pre-press proof.
3.26
OK print
OK sheet

production print (during production printing) singled out as the reference for the remaining production run

3.27
on-press proof print

print produced by press printing (production or proof press) whose purpose is to show the results of the colour

separation process in a way that closely simulates the results on a production press

3.28
positive film polarity

property of a colour separation film (3.7), whose clear and solid areas correspond to unprinted and solid

areas on the print, respectively
3.29
principal axis

axis of a screen that coincides with the direction of the longest diameter of an oblong-shaped (e.g. elliptical or

diamond-shaped) half-tone dot
NOTE Circular and square shaped half-tone dots do not have a principal axis.
3.30
printing condition

set of printing details which fully describe the conditions associated with a specific printed output, usually

associated with characterization data measured from an ISO 12642 or similar target

NOTE Such parameters usually include (as a minimum) printing process, print substrate type, printing ink, screen

type and screen frequency, manner used to produce the printing forme, and surface finish.

3.31
printing forme

tool whose surface is prepared such that some parts transfer printing ink whereas other parts do not

3.32
print substrate
material bearing the printed image
© ISO 2004 – All rights reserved 5
---------------------- Page: 11 ----------------------
ISO 12647-1:2004(E)
3.33
process colours
〈four-colour printing〉 cyan, magenta, yellow, black
3.34
reference direction
〈image〉 horizontal direction as viewed by the end user
3.35
reflectance factor

ratio of the measured reflected flux from the specimen to the measured reflected flux from a perfect-reflecting

and perfect-diffusing material located in place of the specimen
[ISO 5-4]
NOTE The unit is 1.
3.36
reflection densitometer
instrument which measures reflectance factor density (3.37)
3.37
reflection density
reflectance factor density
logarithm to base ten of the reciprocal of the reflectance factor (3.35)
NOTE 1 This definition for reflection density is taken from ISO 5-4.
[3]
NOTE 2 This definition for reflection factor density is taken from CIE 17.4 .
NOTE 3 The unit is 1.
3.38
reflectometer
photometer for measuring quantities pertaining to reflection
[3]
[845-05-26 of CIE 17.4 ]
3.39
relative density

density from which the density of a reference such as the film base, or the unprinted print substrate, has been

subtracted
NOTE The unit is 1.
3.40
sampling aperture size

dimensions of the surface area of a specimen that contributes to the measurement of the reflectance or

transmittance factor density, governed by the design of the instrument
3.41
screen angle

angle (for oblong-shaped half-tone dots) which the principal axis of the screen makes with the reference

direction (3.34), or the smallest angle (for circular and square dot shapes) which an axis of the screen makes

with the reference direction
NOTE Screen angle is expressed in units of degrees.
6 © ISO 2004 – All rights reserved
---------------------- Page: 12 ----------------------
ISO 12647-1:2004(E)
3.42
screen frequency
screen ruling

number of image elements, such as dots or lines, per unit of length in the direction which produces the highest

value

NOTE Screen frequency or screen ruling is expressed in units of reciprocal centimetres.

3.43
screen width
reciprocal of screen ruling (3.42)
NOTE Screen width is expressed in units of micrometres.
3.44
surface finishing

process by which a print is either covered by varnish (lacquer) or laminated with a transparent polymeric film

3.45
tone value

〈data file〉 proportional printing value encoded in a data file and interpreted as defined in the file format

specification
NOTE 1 Tone value is expressed in units of percent.

NOTE 2 Most files store these data as 8-bit integer values, i.e. 0 to 255. The tone value of a pixel is typically computed

from the equation
VV−
A=×100
VV−
100 0
where
V is the integer value of the pixel;
V is the integer value corresponding to a tone value of 0 %;
V is the integer value corresponding to a tone value of 100 %.
100
3.46
tone value
〈film〉 value given in percent as calculated from one of the following equations:
−−()DD
t0
11− 0
for half-tone film of positive polarity, A=×100 , or
−−()DD
11− 0
−−()DD
t0
11− 0
half-tone film of negative polarity, A=×100 1−
−−()DD
11− 0
where
D is the transmittance density of the clear half-tone film;
D is the transmittance density of the solid;
D is the transmittance density of the half-tone.
© ISO 2004 – All rights reserved 7
---------------------- Page: 13 ----------------------
ISO 12647-1:2004(E)

NOTE Formerly known as the film printing dot area. “Dot area” is now a deprecated term.

3.47
tone value

〈print〉 〈printing forme〉 percentage of the surface which appears to be covered by colorant of a single colour (if

light scattering in the print substrate and other optical phenomena are ignored), calculated from the equation

−−()DD
t0
11− 0
A=×100
−−()DD
11− 0
where

D is the reflectance factor density of the unprinted print substrate, or the non-printing parts of the

printing forme;
D is the reflectance factor density of the solid;
D is the reflectance factor density of the half-ton
...

SLOVENSKI STANDARD
SIST ISO 12647-1:2005
01-januar-2005
*UDILþQDWHKQRORJLMD9RGHQMHSURFHVDL]GHODYHUDVWULUDQLKEDUYQLKL]YOHþNRY
SUHVNXVQLKLQSURL]YRGQLKRGWLVRYGHO3DUDPHWULLQPHULOQHPHWRGH

Graphic technology -- Process control for the production of half-tone colour separations,

proof and production prints -- Part 1: Parameters and measurement methods

Technologie graphique -- Maîtrise de procédé pour la production des séparations de

couleur en ton tramé, des épreuves et des tirages en production -- Partie 1: Paramètres

et méthodes de mesurage
Ta slovenski standard je istoveten z: ISO 12647-1:2004
ICS:
37.100.01 *UDILþQDWHKQRORJLMDQD Graphic technology in
VSORãQR general
SIST ISO 12647-1:2005 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ISO 12647-1:2005
---------------------- Page: 2 ----------------------
SIST ISO 12647-1:2005
INTERNATIONAL ISO
STANDARD 12647-1
Second edition
2004-08-01
Graphic technology — Process control
for the production of half-tone colour
separations, proof and production
prints —
Part 1:
Parameters and measurement methods
Technologie graphique — Maîtrise de procédé pour la production des
séparations de couleur en ton tramé, des épreuves et des tirages en
production —
Partie 1: Paramètres et méthodes de mesurage
Reference number
ISO 12647-1:2004(E)
ISO 2004
---------------------- Page: 3 ----------------------
SIST ISO 12647-1:2005
ISO 12647-1:2004(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.

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ISO 12647-1:2004(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

1 Scope...................................................................................................................................................... 1

2 Normative references........................................................................................................................... 1

3 Terms and definitions........................................................................................................................... 2

4 Requirements........................................................................................................................................ 9

4.1 General................................................................................................................................................... 9

4.2 Data file, colour separation films and printing formes ..................................................................... 9

4.3 Proof or production print ................................................................................................................... 11

5 Test methods....................................................................................................................................... 13

5.1 Screen angles...................................................................................................................................... 13

5.2 Tone value on a colour-separation film or of a data file ................................................................. 14

5.3 Tone value on the print....................................................................................................................... 14

5.4 Tone value increase on the print....................................................................................................... 15

5.5 Gloss.................................................................................................................................................... 15

5.6 Spectral measurement, computation of CIELAB colour co-ordinates and CIELAB colour

differences ........................................................................................................................................... 15

Annex A (normative) Reporting ...................................................................................................................... 17

Annex B (informative) Determination of quality parameters of half-tone dots on a colour

separation film..................................................................................................................................... 19

Bibliography ..................................................................................................................................................... 21

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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 12647-1 was prepared by Technical Committee ISO/TC 130, Graphic technology.

This second edition, which has been extensively revised by the introduction of digital data as input, the

addition of several definitions and a general clean up, cancels and replaces the first edition

(ISO 12647-1:1996).

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 printing
 Part 5: Screen printing
 Part 6: Flexographic printing

Part 7: Processes using digital printing or reproductions made on various traditional printing processes from

digital files is in preparation.
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Introduction

When producing a colour reproduction, it is important that the persons responsible for colour separation,

proofing and printing operations have previously agreed on a minimum set of parameters that uniquely defines

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 analogue or digital 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.

It is the purpose of this part of ISO 12647 to list and explain the minimum set of primary process parameters

(see below) required to uniquely define the visual characteristics and related technical properties of a proof or

production print produced directly from digital data or from a set of half-tone separation films. Other parts of

ISO 12647 define specific values for these parameters that are appropriate for specific processes (such as

lithography, gravure, flexography, screen printing). For some processes certain parameters are more

significant than others and may be specified as mandatory while the remainder are optional. However, in this

part of ISO 12647, all parameters are treated equally.

Primary parameters are defined here as having a direct bearing on the visual characteristics of the image;

secondary parameters are defined as those which may 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 film emulsion surface;
 presence of colour marking or register marks;
 printing sequence.

Where necessary for specific process applications, secondary parameters and further related details may be

specified in addition to primary parameters, but they are not included in this part of ISO 12647 except in the

definitions.

During the process of colour separation for multi-colour printing, a digital data set comprising CMYK tone

values ready for printing is normally produced from digital data that relate to a multi-coloured continuous-tone

original. This usually consists of a photographic transparency or a reflection copy print, although any

multicoloured graphic in analogue or digital form may be used as input.

The majority of printing processes covered by ISO 12647 requires continuous-tone images to be broken up

into half-tone screens before they can be put on a printing forme. However, there are new processes like

inkjet that do not require screening. For these processes, this part of ISO 12647 may be equally applied, with

the exception of the specifications for screen width, screen angle, half-tone dot shape and, of course, film

quality. It should be noted that a number of off-press proofing systems produce images without recourse to

half-toning. In this case, the proof cannot be used to predict artefacts like moiré that may be caused by

interferences between periodic structures of the image and half-tones used in production printing.

The process of colour separation does not provide a unique transformation of the colour values of the original

into those of the production print. For every distinguishable spot of the original, the colour (characterizable by

three colorimetric values, e.g. X, Y, Z or L*, a*, b* or hue, saturation and lightness) has to be separated into

tone values for four or more process colours. However, in most cases, the density range (and, hence, the

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colour gamut) of the original is wider than that achievable in printing. As a result, the classical colour

separation process requires some degree of interpretation of the original by the operator and the resultant

transformation may differ from one original to another. With ICC colour management, the mentioned ambiguity

is reduced to vendor-specific options for the user; within a given option set the results are reproducible. A

further source of variation is the degree and manner by which the achromatic component of a colour is

generated with black ink rather than by a suitable mix of the chromatic inks. Here again, a number of options

exist, which may to some degree be vendor-specific.

Whatever freedom exists for the colour separation process, it is important that it take account of the values of

the process parameters of the printing condition to be used for production. This is because the process steps

that follow colour separation, namely output on film (if required), proofing (on- or off-press), the production of

the printing forme (if required), production printing and print surface finishing, are normally carried out with a

rigid set of process parameters which include
 the properties of the print substrate;
 the optical properties of solid prints of the process inks;
 the tone value increase curve.

Maintaining consistent values for the parameters at all steps in the process is important to ensure predictable

reproduction. Any unforeseen variation of these values is usually to the detriment of the visual characteristics

of the image.

The technical background discussed so far shows that the processes of colour separation and proofing

require prior knowledge of the values of the process parameters encountered in production printing. It is

virtually impossible to print all jobs with the same set of process parameters, irrespective of the type of printing

press or digital printing unit, printing forme, printing ink, print substrate, or surface finishing used. Therefore,

there has to be an efficient information exchange between the pre-press service provider, the proof printer and

the production printer which defines the specific parameters for that job.

To facilitate the information interchange, this part of ISO 12647 defines a complete set of parameters whose

values should be specified as a minimum when a pre-press job consisting of a digital file or a set of colour-

separation films, both with accompanying proof print, is being ordered. Specific values for each parameter are

assigned in other parts of ISO 12647; this part is only concerned with definitions, principal requirements,

reporting and test methods.

Because the proof print is the principal means of communication between pre-press, print-buyer and printer, it

is important that

 the proof print be made using the best achievable simulation of the intended printing condition, and

 production printing attempt to match the visual characteristics of the approved proof print.

One of the major variations between and within printing processes is between tone-value-increase curves

(formerly “dot gain curves”), examples of which are shown schematically in Figure 1. One such curve, with

appropriate tolerances, may be specified for every process colour, for each specific combination of print

substrate type and printing process.
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INTERNATIONAL STANDARD ISO 12647-1:2004(E)
Graphic technology — Process control for the production of
half-tone colour separations, proof and production prints —
Part 1:
Parameters and measurement methods
1 Scope

This and other parts of ISO 12647 specify parameters that define printing conditions for the various processes

used in the graphic arts industry. Practitioners wishing to work to common goals may use the values of the

parameters specified in the exchange of data to characterize the intended printing condition and/or for the

process control of printing.
This part of ISO 12647

 defines vocabulary and establishes a minimum set of process parameters that uniquely determine a

printed four-colour half-tone image (which are also referenced from other parts of ISO 12647). The

parameters were selected based on the following process stages “colour separation”, “making of the

printing forme”, “proofing”, “production printing” and “surface finishing”. These are directly applicable to

proofing and printing processes that use colour separation films as input;

 is directly applicable to proofing and printing from printing surfaces produced by filmless methods as long

as direct analogies to film production systems are maintained;

 is 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;

 is applicable to line screens and, where relevant, to those that do not have regular screen angles or

regular screen rulings.
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 5-2, Photography — Density measurements — Part 2: Geometric conditions for transmission density

ISO 5-3, Photography — Density measurement — Part 3: Spectral conditions

ISO 5-4, Photography — Density measurements — Part 4: Geometric conditions for reflection density

ISO 13655, Graphic technology — Spectral measurement and colorimetric computation for graphic arts

images
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3 Terms and definitions

For the purpose of all parts of ISO 12647 the following definitions apply, they are given in alphabetical order.

For convenience, some definitions are included in anticipation of their use in subsequent parts of ISO 12647.

NOTE For quantities, the preferred unit is given together with the definition. By definition, the unit of the so-called

dimensionless quantities is 1.
3.1
achromatic colour
perceived colour devoid of hue, in the perceptual sense
[3]
[adapted from 845-02-26 of CIE 17.4 ]

NOTE 1 The colour names white, grey and black are commonly used or, for transmitting objects, colourless and neutral.

NOTE 2 In printing practice, achromatic colours can be produced either by a single ink or three chromatic inks suitably

balanced.
3.2
axis of a screen

one of the two directions in which the half-tone pattern shows the highest number of image elements, such as

dots or lines, per length
3.3
chromatic colour
perceived colour possessing hue, in the perceptual sense
[3]
[adapted from 845-02-27 of CIE 17.4 ]
NOTE The process inks cyan, magenta and yellow are the chromatic colour inks.
3.4
CIELAB colour difference
CIE 1976 L*, a*, b* colour difference

difference between two colour stimuli defined as the Euclidean distance between the points representing them

in L*, a*, b* space
[3]
[adapted from 845-03-55 of CIE 17.4 ]
NOTE The unit is 1.
3.5
CIELAB colour space
CIE 1976 L* a* b* colour space

three-dimensional, approximately uniform colour space produced by plotting L*, a*, b* in rectangular co-

ordinates
[3]
[adapted from 845-03-56 of CIE 17.4 ]
3.6
colorimeter

instrument for measuring colorimetric quantities, such as the tristimulus values of a colour stimulus

[3]
[845-05-18 of CIE 17.4 ]

NOTE A tristimulus colorimeter achieves this by the analogue integration of the spectral product of object reflectance

or transmittance factor, illuminant and filters which are defined by standard illuminant and the standard observer functions.

A spectrocolorimeter achieves this by calculation from the spectral data.
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3.7
colour-separation film

one of a set of black-and-white half-tone films for process printing that pertains to one process colour

NOTE There are usually four colour-separation films in a set.
3.8
control patch
area produced for control or measurement purposes
3.9
control strip
one-dimensional array of control patches
3.10
core density

〈half-tone film〉 transmittance density in the centre of an isolated opaque image element such as a half-tone

dot or line
NOTE The unit is 1.
3.11
deviation tolerance

permissible difference between the OK print (3.26) from a production run and the reference value

3.12
film emulsion orientation

orientation of a colour separation film relative to the observer with respect to the emulsion side

NOTE Normal orientation is emulsion up, i.e. towards the observer.
3.13
fringe width

〈isolated opaque image element〉 average distance between the density contour lines corresponding to 10 %

and 90 % of the minimum core density specified for the printing process under consideration

NOTE Fringe width is expressed in units of micrometres.
3.14
grey balance

set of tone values for cyan, magenta and yellow on the colour-separation films (3.7) that appears as an

achromatic colour under specified viewing conditions if printed under specified printing conditions

NOTE There are two practical definitions for grey: “a colour having the same CIELAB a* and b* values as the print

substrate” and “a colour that has the same CIELAB a* and b* values as a half-tone tint of similar L* value printed with

black ink”.
3.15
half-tone film

film for use with a half-tone printing process showing image elements such as dots or lines

3.16
hard-dot film

colour-separation film with half-tone dots that reproduce reliably in film duplication and production of the

printing forme
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3.17
ICC colour management

communication, by means of an ICC profile, of the associated data, required for unambiguous interpretation of

colour content data and application of colour data conversions using this profile, as required, to produce the

intended reproductions

NOTE 1 This definition is adapted from that in ISO 15076, which is under preparation.

NOTE 2 Colour content can consist of text, line art, graphics, and pictorial images, in raster or vector from, all of which

can be colour managed.

NOTE 3 Colour management considers the characteristics of input and output devices in determining colour data

conversions for these devices.
[adapted from ISO 15076-1]
3.18
International Color Consortium
ICC

industry body responsible for the ICC profile specification and colour management architecture

3.19
ICC profile
set of colorimetric transforms prepared in accordance with ICC.1
[Reference 4]
3.20
image orientation

orientation of text and images, designated right-reading if text appears as it is intended to be read and images

are in the orientation intended for viewing by the end user and wrong-reading for the opposite

NOTE 1 The film-emulsion orientation requires specification as well: state “emulsion up” or “emulsion down”. “Emulsion

up” is usually assumed if there is no film-emulsion orientation statement.

NOTE 2 A typical reference is “wrong-reading emulsion up” which is equivalent to “right-reading emulsion down”.

3.21
mid-tone spread
quantity defined by the equation
S = max[(A −A ),(A −A ),(A −A )] − min[(A −A ),(A −A ),(A −A )]
c c0 m m0 y y0 c c0 m m0 y y0
where
A is the measured tone value of the cyan process colour image;
A is the specified tone value of the cyan process colour image;
A is the measured tone value of the magenta process colour image;
A is the specified tone value of the magenta process colour image;
A is the measured tone value of the yellow process colour image;
A is the specified tone value of the yellow process colour image.

EXAMPLE For measured values A = 22, A 17 and A = 20 and specified values A = 20, A = 20 and

c m y c0 m0
A = 18):
S = max[(22−20),(17−20),(20−18)] − min[(22−20),(17−20),(20−18)] = 2−(−3) = 5
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3.22
moiré pattern

unwanted periodic structure produced by interference between two or more two-dimensional periodic

structures
3.23
negative film polarity

property of a colour separation film, whose clear and solid areas on the film correspond to solid and unprinted

areas on the print, respectively
3.24
non-periodic half-tone screen
half-tone screen without a regular half-tone dot pattern
3.25
off-press proof print

print produced by a method other than press printing whose purpose is to show the results of the colour

separation process in a way that closely simulates the results on a production press

NOTE Also known as artificial or pre-press proof.
3.26
OK print
OK sheet

production print (during production printing) singled out as the reference for the remaining production run

3.27
on-press proof print

print produced by press printing (production or proof press) whose purpose is to show the results of the colour

separation process in a way that closely simulates the results on a production press

3.28
positive film polarity

property of a colour separation film (3.7), whose clear and solid areas correspond to unprinted and solid

areas on the print, respectively
3.29
principal axis

axis of a screen that coincides with the direction of the longest diameter of an oblong-shaped (e.g. elliptical or

diamond-shaped) half-tone dot
NOTE Circular and square shaped half-tone dots do not have a principal axis.
3.30
printing condition

set of printing details which fully describe the conditions associated with a specific printed output, usually

associated with characterization data measured from an ISO 12642 or similar target

NOTE Such parameters usually include (as a minimum) printing process, print substrate type, printing ink, screen

type and screen frequency, manner used to produce the printing forme, and surface finish.

3.31
printing forme

tool whose surface is prepared such that some parts transfer printing ink whereas other parts do not

3.32
print substrate
material bearing the printed image
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3.33
process colours
〈four-colour printing〉 cyan, magenta, yellow, black
3.34
reference direction
〈image〉 horizontal direction as viewed by the end user
3.35
reflectance factor

ratio of the measured reflected flux from the specimen to the measured reflected flux from a perfect-reflecting

and perfect-diffusing material located in place of the specimen
[ISO 5-4]
NOTE The unit is 1.
3.36
reflection densitometer
instrument which measures reflectance factor density (3.37)
3.37
reflection density
reflectance factor density
logarithm to base ten of the reciprocal of the reflectance factor (3.35)
NOTE 1 This definition for reflection density is taken from ISO 5-4.
[3]
NOTE 2 This definition for reflection factor density is taken from CIE 17.4 .
NOTE 3 The unit is 1.
3.38
reflectometer
photometer for measuring quantities pertaining to reflection
[3]
[845-05-26 of CIE 17.4 ]
3.39
relative density

density from which the density of a reference such as the film base, or the unprinted print substrate, has been

subtracted
NOTE The unit is 1.
3.40
sampling aperture size

dimensions of the surface area of a specimen that contributes to the measurement of the reflectance or

transmittance factor density, governed by the design of the instrument
3.41
screen angle

angle (for oblong-shaped half-tone dots) which the principal axis of the screen makes with the reference

direction (3.34), or the smallest angle (for circular and square dot shapes) which an axis of the screen makes

with the reference direction
NOTE Screen angle is expressed in units of degrees.
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3.42
screen frequency
screen ruling

number of image elements, such as dots or lines, per unit of length in the direction which produces the highest

value

NOTE Screen frequency or screen ruling is expressed in units of reciprocal centimetres.

3.43
screen width
reciprocal of screen ruling (3.42)
NOTE Screen width is expressed in units of micrometres.
3.44
surface finishing

process by which a print is either covered by varnish (lacquer) or laminated with a transparent polymeric film

3.45
tone value

〈data file〉 proportional printing value encoded in a data file and interpreted as defined in the file format

specification
NOTE 1 Tone value is expressed in units of percent.

NOTE 2 Most files store these data as 8-bit integer values, i.e. 0 to 255. The tone value of a pixel is typically computed

from the equation
VV−
A=×100
VV−
100 0
where
V is the integer value of the pixel;
V is the integer value corresponding to a tone va
...

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