ISO 18948:2025

Imaging materials - Photo books - Test methods for permanence and durability

This document specifies test methods to assess the permanence and durability of photo books, including cover and pages. This document is applicable to photo books which contain reflection colour prints made with colour hardcopy materials of all types, including those from either traditional analogue printing or modern digital printing processes. The same performance test methods apply, regardless of the printing process. Because of the large number of combinations of sizes, cover materials, binding options and printing processes, testing of all possible combinations is not within the scope of this document. Instead, a representative selection of printed pages, cover materials and binding options that are used in the makeup of the photo book are tested.

Matériaux pour l’image — Albums photos — Méthodes d’essai de permanence et de durabilité

General Information

• Status: Published
• Publication Date: 25-Feb-2025
• ICS: 37.040.99 - Other standards related to photography
• Technical Committee: ISO/TC 42 - Photography
• Drafting Committee: ISO/TC 42/WG 5 - Physical properties and image permanence of photographic materials
• Current Stage: 6060 - International Standard published
• Start Date: 26-Feb-2025
• Due Date: 04-Dec-2025
• Completion Date: 26-Feb-2025

Relations

• Revises: ISO 18948:2018 - Imaging materials - Photo books - Test methods for permanence and durability
• Effective Date: 08-Jun-2024

Overview

ISO 18948:2025 - Imaging materials - Photo books - Test methods for permanence and durability provides standardized test methods to assess the long‑term performance of photo books. The standard applies to photo books containing reflection colour prints produced by any printing process (analogue or digital). It covers tests for both covers and pages, focusing on the permanence of printed images and the physical durability of the book structure. The 2025 edition is a minor revision of the 2018 edition and is published by ISO/TC 42 (Photography).

Key topics and technical requirements

ISO 18948:2025 defines a structured test program and reporting requirements rather than prescribing pass/fail limits. Major technical topics include:

• Image permanence tests

  • Thermal stability during long‑term dark storage
  • Light stability testing for covers and pages
  • Ozone stability
  • Humidity stability

• Book integrity tests

  • Page pull (binding strength) procedures and calculation methods
  • Peeling, lamination durability, and internal bond strength tests
  • Attachment of book block to cover (heat durability), opening/closing durability

• Blocking and deformation

  • Procedures for testing book blocking under hot/dry, warm/humid and transport conditions
  • Deformation tests: page waviness and cover warp caused by humidity

• Sample selection and reporting

  • Emphasis on testing a representative selection of printed pages, cover materials and binding options rather than every possible combination
  • Detailed requirements for sample preparation, conditioning, and standardized reporting of results

• Annexes

  • Informative guidance on data interpretation, abrasion, extreme tests
  • Normative lamination/delamination procedures and a sandwich thermal test method

Practical applications - who uses this standard

ISO 18948:2025 is relevant to:

• Photo book manufacturers and print service providers for product development and quality control
• Materials and component suppliers (papers, cover stocks, laminates, adhesives) for performance verification
• Independent testing laboratories performing permanence and durability assessments
• Archivists, conservators and collections managers evaluating long‑term preservation
• Procurement and compliance teams assembling specifications and supplier contracts
• Marketers making evidence‑based claims about product durability and permanence

Practical uses include selecting materials and binding methods, establishing QA test plans, comparing suppliers, and documenting product performance for warranty or archival guidance.

Related standards

• Developed by ISO/TC 42 (Photography); other ISO imaging and photographic permanence standards may be relevant when specifying environmental conditions and measurement methods.

For full test procedures, calibration details and reporting templates, obtain the complete ISO 18948:2025 document from ISO.

Standards Content (Sample)

International
Standard
ISO 18948
Second edition
Imaging materials — Photo books
2025-02
— Test methods for permanence
and durability
Matériaux pour l’image — Albums photos — Méthodes d’essai de
permanence et de durabilité
Reference number
© ISO 2025
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Image permanence tests for covers and pages . 4
4.1 General .4
4.2 Sample preparation .4
4.3 Thermal stability during long-term dark storage .5
4.3.1 General .5
4.3.2 Procedures .5
4.3.3 Reporting .5
4.4 Light stability .5
4.4.1 General .5
4.4.2 Covers .6
4.4.3 Pages .6
4.4.4 Reporting .6
4.5 Ozone stability .6
4.5.1 General .6
4.5.2 Covers .6
4.5.3 Pages .7
4.5.4 Reporting .7
4.6 Humidity stability . .7
4.6.1 General .7
4.6.2 Covers and pages .7
4.6.3 Reporting .7
5 Book integrity tests . 7
5.1 General .7
5.2 Ageing conditions .8
5.3 Page pull test .8
5.3.1 General .8
5.3.2 Test procedure.9
5.3.3 Alternate test procedure .9
5.3.4 Calculation of the binding strength .9
5.4 Peeling and lamination durability . .10
5.4.1 General .10
5.4.2 Resistance to delamination .10
5.4.3 Assessment of age related lamination and binding strength .10
5.4.4 Peeling resistance and lamination bond strength for protective laminate .11
5.4.5 Internal bond strength for glued single side sheets .11
5.4.6 Test sample preparation, results assessment and reporting.11
5.5 Book block attachment to the cover (heat durability) . 12
5.5.1 General . 12
5.5.2 Book binding strength (heat durability) . 12
5.5.3 Opening and closing durability . 12
6 Book blocking .13
6.1 General . 13
6.2 Test conditions . 13
6.3 Test target design .14
6.4 Conditioning of test specimen . 15
6.5 Test methods . 15
6.5.1 General . 15
6.5.2 Equipment and calibration .16

iii
6.5.3 Test environment control .16
6.5.4 Long term storage (hot/dry) test .17
6.5.5 Long term storage (warm/humid) test .17
6.5.6 Short term transport test .17
6.6 Evaluation .17
6.6.1 General considerations .17
6.6.2 Reporting .17
6.6.3 Additional evaluations .18
7 Deformation caused by humidity . .18
7.1 Page deformation of a photo book (waviness) .18
7.1.1 General .18
7.1.2 Procedure .18
7.1.3 Reporting .19
7.2 Cover deformation of a photo book (warp) . 20
7.2.1 General . 20
7.2.2 Procedure . 20
7.2.3 Reporting .21
Annex A (informative) Guidelines for data interpretation .22
Annex B (informative) Abrasion .24
Annex C (informative) Extreme photo book tests .26
Annex D (informative) Sandwich thermal test method .29
Annex E (normative) Lamination and delamination testing procedures .31
Bibliography .34

iv
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 42, Photography.
This second edition cancels and replaces the first edition (ISO 18948:2018), of which it constitutes a minor
revision.
The changes are as follows:
— two editorial clarifications in Terms and definitions;
— minor punctuation and grammar changes in Clauses 4 and 6;
— consistency of calculation terms in Clause 7;
— minor editorial clarifications in the annexes.
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.

v
Introduction
Photo books are bound books with printed pages comprised of integrated photos, along with artwork and
text, designed by and usually dedicated to a limited group of people.
Like photographic prints, photo books are produced on the widest available spectrum of production, from
large run commercial facilities to one-off home kits. Their expected permanence and durability can cover
a similarly broad range. Careful consideration should be given to the materials used in the construction of
[33] [34]
photo books to insure high permanence of the printed images and of the books themselves .
Photo books are typically stored in a closed condition, either in a stack or on a book shelf; consequently
environmental factors that may adversely affect displayed prints, such as light and ozone, may not be
applicable to the preservation of the inside pages of a photo book. The user is cautioned that these factors
may become relevant if the photo book is displayed or otherwise exposed to light or other environmental
factors for an extended period of time. ISO 18937 (all parts) and ISO 18941 provide guidelines on testing for
the effect of light and ozone on photo books.
The test methods included in this document assume that the photo book will be stored and used in
environments that may or may not be climate controlled. For this reason, it includes test conditions designed
to assess the adverse effects of humidity and temperature that may be outside of recommended long-term
and medium-term storage conditions as described in ISO 18920. It also includes test conditions intended to
simulate short duration exposure of photo books to the interior of a hot vehicle.
This document contains many specific tests for various binding systems and printing processes. It is not
the intention of this document to require that all possible combinations be tested. Testing all combinations
of sizes, cover materials, binding options and printing processes is not possible due to the large number of
combinations. However, testing representative combinations of materials is encouraged.

vi
International Standard ISO 18948:2025(en)
Imaging materials — Photo books — Test methods for
permanence and durability
1 Scope
This document specifies test methods to assess the permanence and durability of photo books, including
cover and pages.
This document is applicable to photo books which contain reflection colour prints made with colour
hardcopy materials of all types, including those from either traditional analogue printing or modern digital
printing processes. The same performance test methods apply, regardless of the printing process. Because of
the large number of combinations of sizes, cover materials, binding options and printing processes, testing
of all possible combinations is not within the scope of this document. Instead, a representative selection of
printed pages, cover materials and binding options that are used in the makeup of the photo book are tested.
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 527-3, Plastics — Determination of tensile properties — Part 3: Test conditions for films and sheets
ISO 11800:1998, Information and documentation — Requirements for binding materials and methods used in
the manufacture of books
ISO 18924, Imaging materials — Test method for Arrhenius-type predictions
ISO/TR 18931, Imaging materials — Recommendations for humidity measurement and control
ISO 18936, Imaging materials — Processed colour photographs — Methods for measuring thermal stability
ISO 18937 (all parts), Imaging materials — Methods for measuring indoor light stability of photographic prints
ISO 18941:2020, Imaging materials — Colour reflection prints — Test method for ozone gas fading stability
ISO 18946, Imaging materials — Reflection colour photographic prints — Method for testing humidity fastness
ISO 18949, Imaging materials — Reflection colour photographic prints — Method for testing stability under low
humidity conditions
ISO 19594, Graphic technology — Test method for the determination of the binding strength for perfect-bound
products — Page-pull test working upwards
ASTM F904, Standard Test Method for Comparison of Bond Strength or Ply Adhesion of Similar Laminates Made
from Flexible Materials
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp

— IEC Electropedia: available at https:// www .electropedia .org/
3.1
photo book
bound book with printed pages comprised of integrated personal photos along with artwork and text,
designed by and usually dedicated to a limited group of people
3.2
cover
protective covering on the front, back, and spine of a book, including any associated adhesives, binding
boards, liners, and laminates
3.3
blister
localized delamination of a multilayer assembly that looks like a bubble
3.4
delamination
separation of a laminated assembly (3.8) into its constituent layers, either in whole or in part
3.5
laminate
layer of material that goes over one or both sides of a printed page
Note 1 to entry: Usually the laminate layer provides moisture barrier and abrasion resistance, as well as UV shielding,
to add protection to the photo images from physical damage and colour fading.
3.6
laminate
clear polymeric layer applied using thermosetting or pressure-sensitive adhesive to one or both
surfaces of a print to improve durability
3.7
laminate
water-based, solvent-based, or UV-curable liquid protective coating applied to one or both
surfaces of a print to improve durability
3.8
laminated assembly
multilayer structure typically comprising a paper support, one or more barrier layers, an imaging layer, and
a protective laminate (3.5) top layer
Note 1 to entry: Laminated assemblies include films or coatings adhered to the surface of pages or covers, prints
adhered back-to-back to each other forming a completed page.
3.9
lay-flat
binding that allows for an uninterrupted image across the binding either by using flexible, hinged pages or
by using adhesives to adhere the back of two adjacent pages
3.10
sandwich sample holder
metal fixture intended to hold three components in a flattened, pressed-together position so that airflow to
the printed areas of the middle component is restricted as a function of the permeability of the two outer
components
Note 1 to entry: This type of sample holder is suitable for sandwich thermal test method written in Annex D.
3.11
sample sandwich thermal test method
thermal stability test method that complies with ISO 18936 except that the sandwich sample holder (3.10) is
used in place of the free hanging sample holding method

3.12
blocking
undesired adhesion between sheets of printed material that occurs under moderate pressure, high
temperature, or high humidity, while in storage or in use that leads to undesirable effects such as delamination
(3.4), paper splitting, tearing, ferrotyping, colourant transfer, or edge deformation
3.13
sticking
temporary adhesion of prints in a stack or pages in a photo book (3.1) but without physical damage when
adjacent prints or pages are separated
3.14
ferrotyping
changes in surface gloss resulting from intimate contact with another surface, often associated with high
humidity
Note 1 to entry: The term ferrotyping is derived from a historical term associated with silver halide photography. It
is a process used to produce a very high gloss surface on a gelatine silver halide print in which a damp print is placed
in contact with a highly polished surface, such as chromium-plated steel, and dried under conditions of elevated
temperature and pressure.
3.15
bleeding
lateral migration of colourant
3.16
colourant transfer
transfer of colourant from one sheet to the other sheet, when both sheets are placed in direct contact
3.17
cumulative exposure
the aggregated total exposure of a test sample to a series of exposures to a specific condition (e.g., light
intensity) over a specific duration.
Note 1 to entry: For example, receiving five separate exposures to a light intensity of 10 klx for 24 hours each, would
have a cumulative exposure of 1 200 klx-h (5 x 10 x 24)
3.18
curling
physical deformation of a page, a cover, a stack of prints or a bound photo book (3.1) resulting in departure
from physical flatness with the tendency to curve into a concave or convex shape
3.19
wrinkling
physical deformation of a page or a cover of a photo book (3.1) resulting in departure from physical flatness
with the tendency to make furrows, crinkles, folds, ridges or creases
3.20
warp
distortion of the front and/or back covers of a bound book, so that the covers do not lie flat against the book block
3.21
book block
text block, including the endpapers and other materials added by the binder, before casing in
3.22
waviness
physical deformation of a page or a cover of a photo book (3.1) resulting in departure from physical flatness
with the tendency to curve alternately in opposite directions, resembling or suggesting waves

3.23
cockle
planar distortion in flat materials, especially paper or vellum, that is characterized by puckering, waves, or
rippling
3.24
edge fluting
wave-shaped deformation along the edges of cut sheets and can be caused by an expansion of the edge of the
material, which is exposed to greater variations in temperature and humidity than the centre
4 Image permanence tests for covers and pages
4.1 General
Although the individual pages of most photo books are not typically exposed to light and pollutants in the
ambient environment for long periods of time, it is useful to know how stable the printed pages are if the
book were to be left open to the environment for extended periods of time. Therefore, the tests described in
this clause are intended to be carried out on individual printed sheets or pages of a photo book. In addition,
these tests are also intended for photo book covers. Different use profiles are addressed in specification
documents.
Thermal stability, light stability, ozone resistance and humidity resistance of printed sheets and covers
may be evaluated according to the test methods given in ISO 18936, ISO 18937 (all parts), ISO 18941, and
ISO 18946, respectively.
Light stability and ozone resistance, as measured according to ISO 18937 (all parts) and ISO 18941 will
reflect the performance that can be expected for a cover that contains pictures or for the underlying printed
sheets, if a cover has a window opening that shows the first page, or if the book is displayed or otherwise left
in an open state for long periods of time. However the most important issue regarding image permanence of
photo books is generally dark storage.
NOTE Information regarding physical abrasion testing is provided in Annex B.
4.2 Sample preparation
The samples shall consist of the parts of a photo book, including pages, liner and end sheets, and covers,
separated into individual page size components. Printable components, including a printable cover — if
applicable — shall be printed with a test target. These parts are then bound in the same process (time and
machine settings) as the book for which the test is intended. At least two replicate samples are recommended.
Alternatively, test specimens shall be cut off from the book. For general testing purposes, users of this
document are free to choose whatever target patches and starting densities they feel are appropriate for
their testing needs. An example of such a target is included in ISO 18944 along with requirements and
recommendations for sample preparation. Applicable International Standard(s) for specification of print life
may require the use of specific targets. If a protective lamination film or varnish coating is applied to the
photo book, either on the book cover or in its inner sheets, the same protective film or varnish coating shall
be applied on the test samples. The photo book components shall be conditioned at 23 °C and 50 % RH for
24 h prior to testing.
NOTE Be aware that different starting densities of the test prints may yield different test results in terms of fading
rate. Once a test sample density is chosen, it is important to be consistent across all test samples for comparison. If
testing is being done according to a standard that uses specific starting densities it is important that those densities
be adhered to.
At least two replicate samples of each photo book component part are required, both printed and unprinted.
Replicates of each photo book component part shall be located in different regions of the respective test
chambers (light, ozone, etc.).
The measurement and sample holding conditions and measurement procedures given in ISO 18936 shall
be followed. In particular, care shall be taken to use consistent ambient light levels and hold times in each

iteration of the sample holding and measurement process. Density shall be measured for printed patch
areas, and colorimetric values shall be measured in the D (minimum density) patch areas of the printable
min
components and in the centre, of each unprinted component. Density and colorimetric values from the
replicate samples shall be averaged before calculations are performed.
4.3 Thermal stability during long-term dark storage
4.3.1 General
Long term stability shall be evaluated in accordance with ISO 18936, the test method, and ISO 18924, the
Arrhenius analysis. It should be noted that the test results of the short term high temperature test may not
correspond to the long term stability.
4.3.2 Procedures
The sealed bag method, as detailed in ISO 18936, shall be used to test individual pages or covers. In addition
to the required sealed bag method, the ‘free hanging’ method, also detailed in ISO 18936, may be used to
minimize page or cover interactions; it does not, however, reflect the actual storage conditions of the photo
book. The ‘free hanging’ test does not simulate interactions between components that may be present in
a photo book, such as between the cover and the first page. To simulate those interactions the user may
conduct a “sandwich” type thermal ageing test as described in Annex D.
During actual storage of photo books the temperature and humidity will fluctuate, including potentially large
fluctuations depending on the differences in seasons. The testing shall be done at a relative humidity (RH)
of 50 %. However, because the effects of humidity on image stability can differ markedly from one product
to another, it is useful to evaluate its effect. This is done by means of a temperature test series carried out at
different relative humidity. If the relative humidity during storage is expected to be significantly lower than
50 % RH, such as when stored in accordance with some conditions specified in ISO 18911, ISO 18920 or in an
arid climate, or significantly higher, as in a tropical climate, the relative humidity selected for the test should
correspond to the storage conditions. Such tests are often conducted at conditions of various % RH levels,
such 20 % RH to pick up low humidity effects and 70 % RH to pick up high humidity effects. In order to make
use of the Arrhenius method in ISO 18924, the temperatures used shall span a minimum range of 20 °C.
4.3.3 Reporting
Reporting shall comply with the reporting requirements of ISO 18936. The results of these tests are
reported as temperatures and time for thermal testing to reach the observed losses in optical densities,
together with the percentage of optical density losses, or the amount of densitometric and/or colorimetric
change observed for a given temperature and time. Reporting shall include results for each tested photo
book component, printed and unprinted. For each photo book component, reporting shall also include the
presence or absence of physical and biological changes including, but not limited to, delamination, adhesive
failure, mould growth, and blocking. In particular, if a sample photo book component held in the interior of
a three-layer sandwich in the sandwich sample holder adheres to or transfers colourant to the materials
comprising the outer layers of the three-layer sandwich, this failure shall be reported. In addition, visible
edge yellowing, differentiating the component edge region from the interior shall be reported.
4.4 Light stability
4.4.1 General
The test method for “simulated indoor daylight typical home display” according to ISO 18937 (all parts), shall
be used. For general testing purposes, users of this document are free to choose whatever target patches and

starting densities they feel are appropriate for their testing needs. An example of such a target is included in
ISO 18944 along with requirements and recommendations for sample preparation.
NOTE Be aware that different starting densities of the test prints can yield different test results in terms of fading
rate. Once a test sample density is chosen, it is important to be consistent across all test samples for comparison. If
testing is being done according to a standard that uses specific starting densities it is important that those densities
be adhered to.
4.4.2 Covers
The total cumulative exposure shall be 20 Mlx·h. Data may also be collected at lower and higher cumulative
exposures if applicable to the usage case.
4.4.3 Pages
The total cumulative exposure shall be 2 Mlx·h. Data may also be collected at lower and higher cumulative
exposures if applicable to the usage case.
NOTE The total cumulative exposure of 20 Mlx·h corresponds to 25 y exposure assuming that 12 h a day at a light
level of 200 lx. 200 lx is the light level for book shelves at library which is described in ISO/CIE 8995-1. The pages are
typically not exposed to as much light as the covers, and it is estimated to be less than ten percent of the cover value.
4.4.4 Reporting
Reporting shall comply with the reporting requirements of ISO 18937 (all parts). The results of these
tests are reported as the amount of densitometric or colorimetric change observed for a given cumulative
exposure (lx·h) together with the percentage losses in optical densities. If multiple exposures are used, the
results are reported as the cumulative exposure to reach the observed densitometric or colorimetric change
together with the percentage losses in optical densities.
4.5 Ozone stability
4.5.1 General
The test method described in ISO 18941 shall be used. For general testing purposes, users of this document
are free to choose whatever target patches and starting densities they feel are appropriate for their testing
needs. An example of such a target is included in ISO 18944 along with requirements and recommendations
for sample preparation.
NOTE Be aware that different starting densities of the test prints can yield different test results in terms of fading
rate. Once a test sample density is chosen, it is important to be consistent across all test samples for comparison. If
testing is being done according to a standard that uses specific starting densities it is important that those densities
be adhered to.
4.5.2 Covers
The total cumulative exposure shall be 1 450 μl/l·h. Data may also be collected at lower and higher
cumulative exposures if applicable to the usage case. Unless otherwise specified, the test shall be carried
out at 1,0 μl/l, with an operational uniformity of ±0,1 μl/l ozone as specified in ISO 18941:2020, 9.4. Other
optional concentrations, such as 0,5 μl/l or 5,0 μl/l, may be useful for testing. If concentrations other than
1,0 μl/l are used, the operational uniformity tolerances shall be ±10 % of aim or the best achievable with
the test equipment. If greater than ±10 %, the actual tolerance shall be reported. If optional concentrations
are used, the tester should evaluate the materials for ozone reciprocity behaviour before making any
comparative conclusions. For testing at ozone concentrations greater than 1,0 μl/l, reciprocity testing shall
be conducted at an ozone concentration of 1,0 μl/l or lower (as discussed in ISO 18941:2020, Annex B).
−6
NOTE 1 μl/l = 1 ppm (1 × 10 ) and is measured in terms of volume.

4.5.3 Pages
The total cumulative exposure shall be 145 μl/l·h. Data may also be collected at lower and higher cumulative
exposures if applicable to the usage case. Unless otherwise specified, the test shall be carried out at 1,0 μl/l,
with an operational uniformity of ±0,1 μl/l ozone as specified in ISO 18941:2020, 9.4. Other optional
concentrations, such as 0,5 μl/l or 5,0 μl/l, may be useful for testing. If concentrations other than 1,0 μl/l
are used, the operational uniformity tolerances shall be ±10 % of aim or the best achievable with the test
equipment. If greater than ±10 %, the actual tolerance shall be reported. If optional concentrations are used,
the tester should evaluate the materials for ozone reciprocity behaviour before making any comparative
conclusions. For testing at ozone concentrations greater than 1,0 μl/l, reciprocity testing shall be conducted
at an ozone concentration of 1,0 μl/l or lower (as discussed in ISO 18941:2020, Annex B).
NOTE The total cumulative exposure of 1 450 μl/l·h corresponds to 25 y exposure to ozone gas of 6,6 nl/l
concentration. Median ambient indoor ozone concentrations of 9 nl/l and 4,5 nl/l were determined for different
regions worldwide. The 6,6 nl/l is the half point of the discussion. The pages are typically not exposed to as much
ozone as the covers, and it is estimated to be less than ten percent of the cover value.
4.5.4 Reporting
Reporting shall comply with the reporting requirements of ISO 18941:2020, Clause 10. The results of these
tests are reported as the amount of densitometric or colorimetric change observed for a given cumulative
exposure (μl/l·h) together with the percentage losses in optical densities. If multiple exposures are used, the
results are reported as the cumulative exposure to reach the observed densitometric or colorimetric change
together with the percentage losses in optical densities.
4.6 Humidity stability
4.6.1 General
The test method and target patches described in ISO 18946 and ISO 18949 shall be used.
4.6.2 Covers and pages
The tests of Method A of ISO 18946 (high humidity) and ISO 18949 (low humidity) shall be run and results
reported as described in ISO 18946 and ISO 18949.
4.6.3 Reporting
Reporting shall comply with the reporting requirements of ISO 18946 and ISO 18949. Reporting the specific
humidity fastness test result (Method A of ISO 18946 and ISO 18949) shall include reporting of the humidity
(% RH) and temperature test conditions, the test time duration and the delta E resulting over the test
duration. For each photo book component, reporting shall also include the presence or absence of physical
and biological changes including, but not limited to, delamination, adhesive failure, mould growth, and
blocking.
5 Book integrity tests
5.1 General
Testing the book integrity of a photo book is conducted by a set of mechanical durability tests, which are
related to transportation, usage, and storage on a bookshelf.
In general, some material used as binding or lamination may degrade gradually with age. Therefore, each
mechanical durability test is performed on a photo book in its initial state and after a period of short term ageing.

Test methods of book integrity consist of page-pull test, peeling and delamination tests (including for covers
and pages), and book block attachment to the cover.
NOTE 1 Page adhesion of a photo book caused by heat and humidity is addressed in Clause 6.
NOTE 2 Deformation of a photo book caused by heat and humidity is addressed in Clause 7.
NOTE 3 Information in extreme tests for photo book integrity is provided in Annex C.
5.2 Ageing conditions
Parameters of accelerated sample ageing for assessing the changes in ageing related mechanical integrity
include: temperature range, relative humidity set point and total test duration. Users of this document
are encouraged to select a proper set of test conditions based on their application needs and the expected
storage environment in the life-cycle of the photo book products for the market they are servi
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