ISO/TS 15311-1:2019

TECHNICAL ISO/TS
SPECIFICATION 15311-1
Second edition
2019-02
Graphic technology — Print quality
requirements for printed matter —
Part 1:
Measurement methods and reporting
schema
Technologie graphique — Exigences de qualité d'impression pour les
imprimés —
Partie 1: Méthodes de mesure et schémas de rapport
Reference number
ISO/TS 15311-1:2019(E)
©
ISO 2019

---------------------- Page: 1 ----------------------
ISO/TS 15311-1:2019(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/TS 15311-1:2019(E)

Contents Page
Foreword .iv
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Requirements . 3
4.1 General . 3
4.2 Single or multiple sheet assessment . 4
4.2.1 Total number of sheets . 4
4.2.2 Number of sheets measured . 4
4.2.3 Reporting . 5
4.3 Print quality measures . 5
4.3.1 Overview . 5
4.3.2 Colour, tone reproduction and gloss . 6
4.3.3 Uniformity .12
4.3.4 Detail rendition capabilities .15
4.3.5 Permanence . .18
4.3.6 Artefacts .24
4.4 Printing conditions .24
Annex A (informative) Sampling of sheets .25
Annex B (informative) Estimation of BlackPoint from control strip .27
Annex C (informative) Calculation of 95th percentile .28
Bibliography .31
© ISO 2019 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO/TS 15311-1:2019(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 130, Graphic technology.
This second edition of ISO/TS 15311-1 cancels and replaces the first edition (ISO/TS 15311-1:2016),
which has been technically revised.
The main changes compared to the previous edition are as follows:
a) All references are now undated, unless reference is made to a specific element of the cited document.
b) 4.3.2.3 Absolute colour reproduction (process colours)
1) Title changed to: Colour accuracy (absolute colour reproduction, process colours).
c) 4.3.2.4 Media relative colour reproduction (process colours)
1) Title changed to: Colour accuracy (media relative colour reproduction, process colours).
d) Subclauses added:
1) 4.3.2.5 Colour accuracy (media relative colour reproduction with BlackPoint compensation)
2) 4.3.2.7 Colour accuracy (spot colours)
3) 4.3.3.7 Print-through resistance
4) 4.3.4.8 Registration
5) 4.3.5.5 Water resistance
6) 4.3.5.6 Scratch resistance
7) 4.3.5.7 Abrasion resistance (transportation of sheets)
iv © ISO 2019 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/TS 15311-1:2019(E)

8) 4.3.6.1 Background extraneous marks and voids (monochrome)
e) Annex B added
1) Estimation of BlackPoint from control strip
f) Annex C added
1) Calculation of 95th percentile
g) 4.3.2.4 Colour accuracy (media relative colour reproduction, process colours) modified
1) Reference colour values are now adjusted instead of adjusting measurement values as in the
published version of this standard. This was done to be consistent with the method used to
assess media relative colour reproduction with BlackPoint compensation.
A list of all parts in the ISO/TS 15311 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
© ISO 2019 – All rights reserved v

---------------------- Page: 5 ----------------------
ISO/TS 15311-1:2019(E)

Introduction
When producing a colour reproduction, it is important that the persons responsible for data creation,
colour separation, proofing and printing operations have previously agreed a minimum set of
parameters that define the visual characteristics and other technical properties of the planned print
product. This document identifies a number of metrics that can be applied to printed sheets and that
can be used as the basis for such communication. The range of metrics is large and it is not intended
that all of these metrics are to be applied to any given printed product and for any given application,
the range of metrics is to be carefully selected, for example based on subsequent parts of ISO/TS 15311.
The metrics described by this document can be applied to any type of print. They are likely most often
to be applied to digitally printed prints.
When selecting the set of metrics, only those metrics that have a clear specification and that correlate
well with human perception are included in this document. Since this is an area of significant research
activity, new metrics are expected to emerge and existing metrics to be revised in the next few years.
For this reason, we anticipate the need to revise this document within a very short time scale as new
metrics are tested and found to be reliable.
Additional tests to those specified in this document, for example visual assessment of smoothness,
images and other elements may be required when assessing print quality.
As with any parameter that is used as part of a product specification, it is important for readers to
understand clearly what the metric means. For this reason, a reporting schema is to be followed when
reporting measurements in conformance with this document.
vi © ISO 2019 – All rights reserved

---------------------- Page: 6 ----------------------
TECHNICAL SPECIFICATION ISO/TS 15311-1:2019(E)
Graphic technology — Print quality requirements for
printed matter —
Part 1:
Measurement methods and reporting schema
1 Scope
This document defines print quality metrics, measurement methods and reporting requirements for
printed sheets that are suitable for all classes of printed products.
Guidance as to which of these metrics to apply to any given product category along with acceptable
conformance criteria is provided in subsequent parts of ISO/TS 15311.
Although this document is expected to be used primarily to measure prints from digital printing
systems, the metrics are general and may be applied to other kinds of print.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 2813, Paints and varnishes — Determination of gloss value at 20°, 60° and 85°
ISO 8254-1, Paper and board — Measurement of specular gloss — Part 1: 75° gloss with a converging beam,
TAPPI method
ISO 12642-2, Graphic technology — Input data for characterization of 4-colour process printing — Part 2:
Expanded data set
ISO 12647-8, Graphic technology — Process control for the production of half-tone colour separations,
proof and production prints — Part 8: Validation print processes working directly from digital data
ISO 13655, Graphic technology — Spectral measurement and colorimetric computation for graphic
arts images
ISO 15184, Paints and varnishes — Determination of film hardness by pencil test
ISO 18619, Image technology colour management — Black point compensation
ISO 18924, Imaging materials — Test method for Arrhenius-type predictions
ISO 18930, Imaging materials — Pictorial colour reflection prints — Methods for evaluating image stability
under outdoor conditions
ISO 18935, Imaging materials — Colour images — Determination of water resistance of printed colour images
ISO 18936, Imaging materials — Processed colour photographs — Methods for measuring thermal stability
ISO 18937:2014, Imaging materials — Photographic reflection prints — Methods for measuring indoor
light stability
ISO 18947, Imaging materials — Photographic reflection prints — Determination of abrasion resistance of
photographic images
© ISO 2019 – All rights reserved 1

---------------------- Page: 7 ----------------------
ISO/TS 15311-1:2019(E)

ISO/IEC 24790, Information technology — Office equipment — Measurement of image quality attributes
for hardcopy output — Monochrome text and graphic images
ISO/IEC 29112, Information technology — Office equipment — Test pages and methods for measuring
monochrome printer resolution
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
banding
appearance of one dimensional variation within an area that should be homogeneous
3.2
CIEDE2000 colour difference
total colour difference as defined in ISO/CIE 11664-6:2014 (CIE S 014-6/E:2013)
Note 1 to entry: The unit is ΔE . The default weights for lightness, chroma and hue are (1:1:1).
00
3.3
colour deviation
colour difference between the colour aim value and a colour measurement or the mean of a set of colour
measurements
Note 1 to entry: In addition to the ΔE the ΔL* with Δa* and Δb* and/or with ΔC* and ΔH* may be reported.
00
3.4
colour variation
colour difference between the mean of a set of colour measurements and each sample
Note 1 to entry: Colour variation is also known as colour fluctuation and may be reported as the mean or 95th
percentile.
3.5
digital print
print where the image is printed directly from the digital domain
Note 1 to entry: Digital printing is a process for text and image reproduction with a colour marker on a medium
using a marking device, on which the marking information is generated from digital data directly to the medium.
It differs from traditional ink-based printing on which the marking information is generated from a form
produced offline prior to imaging on the medium.
[SOURCE: ISO 18913:2012]
3.6
permanence
ability to remain chemically and physically stable over long periods of time
[SOURCE: ISO 18913:2012, 3.134]
2 © ISO 2019 – All rights reserved

---------------------- Page: 8 ----------------------
ISO/TS 15311-1:2019(E)

3.7
image quality
impression of the overall merit or excellence of an image, as perceived by an observer
Note 1 to entry: For a meaningful technical evaluation of image quality, the evaluation should be based on a
third-party assessment, i.e. by an observer neither associated with the artistic creation of the image, nor closely
or emotionally involved with the subject matter being depicted. This restriction is designed to eliminate sources
of variability that arise from more idiosyncratic aspects of image perception that are outside control of imaging
system designers.
[SOURCE: Handbook of Image Quality: Characterization and prediction, by Brian W. Keelan]
3.8
printing condition
set of primary process parameters which describe the conditions associated with a specific printed
output, associated with spectral, colorimetric and/or densitometric aim values
Note 1 to entry: Such parameters usually include (as a minimum) printing process, paper category, printing ink,
screening and printing sequence. The aim values typically comprise the colorant description and tone value
increase aims.
Note 2 to entry: For the purposes of colour management, a printing condition is fully characterized by giving the
relationship between the digital input values (for example as stipulated in ISO 12642-2) and the corresponding
measured colorimetric values.
Note 3 to entry: Based on a given set of characterization data according to 3.9, Note 2 entry and a definition of
achromatic perception, a grey printing condition might be extracted.
3.9
tone value
proportional printing value encoded in a data file and interpreted as defined in the file format
specification
VV−
 
p 0
A=×100 %
 
VV−
 
100 0
where
V is the integer value of the pixel;
p
V is the integer value corresponding to a tone value of 0 %;
0
V is the integer value corresponding to a tone value of 100 %.
100
Note 1 to entry: Tone value is expressed in units of percent.
Note 2 to entry: 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 formula.
3.10
URI
Uniform Resource Identifier as specified by the World Wide Web Consortium (W3C)
4 Requirements
4.1 General
The following sub-clauses provide a number of metrics that define attributes of printed sheets and
requirements for reporting them.
© ISO 2019 – All rights reserved 3

---------------------- Page: 9 ----------------------
ISO/TS 15311-1:2019(E)

In many cases, the existing standards use CIE ΔE* rather than CIEDE2000. Although these are not
ab
interchangeable quantities, ΔE* has been superseded by CIEDE2000 in ISO/TC 130 standards. For
ab
this reason, CIEDE2000 shall be used to report colour difference metrics in this document.
Similarly, printing density is seldom used to measure colour and where the referenced standards
specify printing density, approximately equivalent CIELAB colour measurements shall be used.
4.2 Single or multiple sheet assessment
Unless otherwise specified, metrics shall be assumed to apply to the assessment of a single sheet.
In many cases, it is useful to be able to report metrics for a set of sheets; for example, the set of sheets
produced in a single print run or the set of sheets to be delivered as part of an order for print. In these
cases, it is important to be able to indicate the likely variation across the entire set of sheets.
Sheets should be selected randomly with no replacement.
NOTE Best practice sampling is time-stamped to demonstrate what time and date the sample was taken.
Samples should be selected with the following provisos:
a) sheets should be selected throughout the entire press run;
b) sheets should not be selected synchronous to any press event, e.g. at each roll change or after every
blanket wash.
In cases where metrics are reported for a set of sheets, the report shall indicate the following: the total
number of sheets in the set to be assessed, the number of sheets measured and, unless random selection
with no replacement is used, the sampling method used to select the sheets shall be indicated.
4.2.1 Total number of sheets
The total number of sheets in the set of sheets assessed shall be reported. Details of the printing system
used to create the sheets should also be reported.
4.2.2 Number of sheets measured
Conformance with this document requires only that values measured for the sampled set of sheets are
reported. As a general rule, the higher the number of sheets measured from the set, the closer this value
will be to that of the entire set of sheets. Where there are a large number of sheets in the set, it may be
impractical to measure a high percentage of these sheets and so the likely spread of values may be high.
Table 1 provides guidelines for the suggested number of sheets to be assessed for different numbers of
sheets in the set.
Table 1 — Guidelines for the number of sheets to be assessed
Total number of Suggested number of
sheets in set sheets to be measured
50 12
100 13
1 000 and greater 15
Table 1 provides typical sampling strategies used in the industry today. Users should be aware that
where these values are used, the average value (and the 95th percentile) for the total set of sheets may
vary substantially from the average measured for the sample set. Annex A provides details of how
the likely difference between these two values varies with the sample size and provides a method for
finding the sampling rate needed to increase the confidence in the metric to a required level.
NOTE ISO 186 Paper and board — Sampling to determine average quality suggests increasing the number of
samples to 20 for run lengths greater than 5000.
4 © ISO 2019 – All rights reserved

---------------------- Page: 10 ----------------------
ISO/TS 15311-1:2019(E)

In order to verify whether the difference between the two values is statistically significant, the variable
E of Annex A can be used as a point of reference. The number of samples may be chosen to avoid
overlapping error bars by selecting an appropriate value for E.
4.2.3 Reporting
When multiple sheets are assessed, the total number of sheets and the number of sheets assessed shall
be reported as shown in the example below.
EXAMPLE 1 Sheets assessed: 15 (500).
When multiple sheets are assessed, the mean and standard deviation for each metric shall be reported
as shown below except when reporting colour difference metrics.
EXAMPLE 2 Estimated line width: sample mean = 0,12 mm, sample standard deviation = 0,01 mm.
When reporting colour difference metrics for a single colour measured on multiple sheets, both the
colour deviation and colour variation should be reported.
The colour deviation shall be calculated as follows: calculate the mean CIELAB value of the samples. The
colour deviation is given by the CIEDE2000 colour difference between the CIELAB colour aim value and
the mean CIELAB value. In addition to the ΔE value the ΔL*, Δa* and Δb* values (Mean - Reference)
00
should be reported.
EXAMPLE 3 Colour deviation 3,2 ΔE , ΔL* = 2,8, Δa* = 0,3, Δb* = 1,4.
00
The colour variation shall be calculated as follows: calculate the mean CIELAB value of the samples.
Calculate the CIEDE2000 colour differences between this mean and the CIELAB of each sample. The
colour variation is given by the mean value of these CIEDE2000 colour differences or the corresponding
95th percentile. Refer to Annex C for details on the calculation of the 95th percentile.
EXAMPLE 4 Colour variation 0,8 DE .
00
Where the spread of colour variation is reported, the mean colour difference and the 95th percentile
(and not the standard deviation) should be used.
EXAMPLE 5 Colour variation 0,8 DE , 95th percentile 1,2 DE .
00 00
NOTE 1 Standard deviation is not an appropriate measure for colour difference as this assumes a normal
distribution, whereas colour differences are not normally distributed. The 95 percentile provides a more reliable
estimate of the spread of values.
NOTE 2 The parameters of arithmetic average (mean from a small sample set) and 95th percentile are well
known and easy to compute. But, neither parameter is insensitive to the changes in the underlying distribution
of readings or the presence of erroneous or outlier readings (statistical robustness). With the small numbers
of readings being collected, a single bad read could move either the mean or the 95th percentile several points
further away from their ideal values. When reporting these parameters, if the results are much larger than
expected, then the data should be examined for values that are much larger than the rest of the sample. If this is
the case, then that reading should be examined to determine if there is a cause for this difference and this may
provide justification to leave that outlier out of the analysis.
Colour errors across multiple sheets shall be calculated and reported as follows. For all patches on all
sheets, calculate the colour error between the patch and the corresponding reference colour. This results
in a total of n x m colour errors where n is the number of colour patches on each sheet and m is the
number of sheets. Calculate and report the mean and 95th percentile of this entire set of colour errors.
4.3 Print quality measures
4.3.1 Overview
Image quality metrics or attributes are aspects, dimensions or components of overall perceived print
image quality.
© ISO 2019 – All rights reserved 5

---------------------- Page: 11 ----------------------
ISO/TS 15311-1:2019(E)

The visual attributes specified in this document, to be used by the remaining parts of ISO/TS 15311, are
defined in the following clauses.
4.3.2 Colour, tone reproduction and gloss
4.3.2.1 General
Colour accuracy describes the visual closeness between a defined reference and a reproduction. It is
important to distinguish two concepts: absolute and media relative colour accuracy.
Absolute colour accuracy is usually required for side-by-side viewing, whereas media relative colour
accuracy is usually more desirable for sequential viewing where the prints being compared are never
viewed together.
When selecting a suitable metric, it is important to know which kind of comparison is expected and
when reporting colour metrics, the colour accuracy method and the intended evaluation method should
be indicated.
4.3.2.2 Print substrate
In some cases, it may be desirable to indicate the substrate that is used when reporting other attributes.
For example, the colour accuracy achieved for a particular reference printing condition usually depends
on the substrate. This is only likely to be useful for cases where isotropic (paper-like) substrates are used.
When such substrate attributes are included they shall be reported as shown in Table 2.
Table 2 — Substrate reporting requirements
Print substrate attribute Description Example
Substrate name (Required) A text string that Substrate name: StoraEnso NovaPress
provides details of the substrate
used. This should include suffi-
cient
detail to enable purchase of simi-
lar substrate.
Substrate colour (Required) CIELAB D50/2° M1 Substrate colour: (95,0.5, −2) CIELAB
colour value of the substrate
measured as specified in
ISO 13655
Other metrics from (Optional) Report metric as indicated in ISO 15397
ISO 15397 may be reported
4.3.2.3 Colour accuracy (absolute colour reproduction, process colours)
In some cases, particularly when proofing, it is useful to be able to estimate the accuracy to which the
print simulates a reference printing condition and this attribute is called “absolute colour accuracy”.
When reported, assessment of absolute colour accuracy shall be performed by printing and measuring
an ISO 12642-2 characterization data chart or where appropriate a subset of these patches (control
strip patches) according to ISO 12647-8 (Validation print control strip).
NOTE Where the option to preserve 100 % K elements is used, the 100 % K patch on the control strip is
likely to include an unexpected error.
The values shown in Table 3 shall be reported using the measurement units shown and values shall be
reported to two significant figures.
6 © ISO 2019 – All rights reserved

---------------------- Page: 12 ----------------------
ISO/TS 15311-1:2019(E)

Table 3 — Reporting absolute colour reproduction parameters
Description Full label Abbreviated label Units
Colour difference for substrate Substrate Sub ΔE
00
Maximum colour difference for all control Control strip maximum CSMax ΔE
00
strip patches
The 95th percentile for the control strip Control strip 95th percentile CS95 % ΔE
00
patches
Average colour difference for control Control strip average CSAve ΔE
00
strip patches
Maximum chromaticness difference for Control strip neutrals maximum CSMaxNeutral ΔC
h
1
CMY neutral control strip patches
Average chromaticness difference for CMY Control strip neutrals average CSAveNeutral ΔC
h
neutral control strip patches
Average colour difference for selected Characterization chart surface CCAveSurface ΔE
00
surface gamut patches patches average
The average colour difference for the Characterization chart average CCAve ΔE
00
characterization chart
The 95th percentile for the characteriza- Characterization chart 95th CC95 % ΔE
00
tion chart percentile
1 See ISO 13655 for the description of ΔC and the method of calculation.
h
NOTE  Technically speaking the ‘unit’ in this table represents the method by which the value is calculated.
EXAMPLE 1 Absolute colour accuracy: Sub (1,2 ΔE ), CSMax (8,0 ΔE ), CS95 % (6,0 ΔE ), CSAve (3,0 ΔE
...