SIST ISO 18912:2011

INTERNATIONAL ISO
STANDARD 18912
First edition
2002-11-01
Imaging materials — Processed vesicular
photographic film — Specifications for
stability
Matériaux pour l'image — Film photographique vésiculaire traité —
Spécifications relatives à la stabilité

Reference number
©
ISO 2002
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ii © ISO 2002 – All rights reserved

Contents Page
Foreword . iv
Introduction. v
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 2
4 Film base requirements. 3
5 Processed film requirements. 3
5.1 Safety film. 3
5.2 Tensile properties and loss in tensile properties . 3
6 Requirements for the emulsion and backing layers of processed film. 4
6.1 Layer adhesion. 4
6.2 Blocking. 4
6.3 Binder stability. 4
6.4 Thermal sticking. 4
7 Image stability requirements. 4
7.1 Proper development. 4
7.2 Residual diazonium-salt test. 5
7.3 Light-fading. 5
7.4 Dark-ageing of minimum-density area. 5
7.5 Dark-ageing of vesicular image . 5
8 Test methods. 5
8.1 Identification of film base. 5
8.2 Accelerated-ageing conditions. 6
8.3 Tensile-property test for processed film . 6
8.4 Tape-stripping adhesion test . 7
8.5 Humidity-cycling adhesion test . 8
8.6 Blocking test. 8
8.7 Thermal sticking test . 9
9 Image test methods. 9
9.1 Densitometry. 9
9.2 Proper development test . 9
9.3 Residual diazonium-salt test. 9
9.4 Light-fading test. 10
9.5 Dark-ageing test for the minimum-density area . 10
9.6 Dark-ageing test for the vesicular image. 11
10 Classification for reporting. 11
Annex A (informative) Numbering system for related International Standards. 12
Annex B (informative) Distinction between film storage (record) copies and work (reference) copies. 14
Annex C (informative) Microfilm image quality. 15
Annex D (normative) Effects of heat and pressure. 17
Annex E (informative) Effects of high humidity. 18
Annex F (informative) Light-fading of vesicular images. 19
Annex G (informative) Corrosiveness . 20
Bibliography. 21

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 3.
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 International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 18912 was prepared by Technical Committee ISO/TC 42, Photography.
ISO 18912 cancels and replaces the second edition of ISO 9718:1995, of which it constitutes a technical revision.
This International Standard is one of a series of International Standards dealing with the physical properties and
stability of imaging materials. To facilitate identification of these International Standards, they are assigned a
number within the block from 18900 – 18999 (see annex A).
Annexes A to G of this International Standard are for information only.
iv © ISO 2002 – All rights reserved

Introduction
Since 1930, great advances have been made in the use of photographic films for the preservation of records. The
preservation of records on film by national, state and municipal governments, by banks, insurance companies,
industry and other enterprises has been stimulated by recognition of the resultant economies in storage space,
organization, accessibility and ease of reproduction. The safe-keeping of pictorial film records having legal,
scientific, industrial, medical, historical, military or other values has also become increasingly important.
The use of film for records having long-term values necessitated the development of International Standards to
specify the characteristics of film suitable for this purpose. ISO 18901 specifies the requirements for silver-gelatin
films which are suitable for storage. This International Standard (for vesicular film) and ISO 18905 (for diazo film)
give the requirements for photographic duplicate films suitable for storage.
The term “archival film” has been discontinued and the new concept of “life expectancy” is introduced. Film life is
classified by the LE or life expectancy rating as defined in this International Standard. For example, LE-100
represents film with a life expectancy of 100 years when stored at 21 °C and 50 % RH.
Criteria for properties of LE-10 and LE-100 vesicular films are based upon the dark-ageing stability of D

min
processed areas. Different dark-incubation tests are specified for LE-10 and LE-100 films. All other properties and
processing requirements for medium and long-term vesicular films are identical.
In addition to tests to ensure that the density of D areas does not increase to unacceptable levels during storage,

min
a test is also specified on high-density areas. This is to guard against the possibility of vesicle (or bubble) collapse
during storage. This test has to be carried out at temperatures below the softening point of the image binder, as
tests above this temperature have no practical meaning (see [1], [2] in the bibliography). However, to give
confidence of acceptable image stability, the permissible density change was set as low as possible, in line with the
measurement error of the densitometer. Both LE-10 and LE-100 vesicular films shall meet the same requirement.
It is recognized that vesicular images may show density changes after exposure to light. However, this International
Standard covers only films used as storage copies, not as work copies (as defined in annex B). The light-fading
requirements specified in this International Standard ensure satisfactory behaviour for storage copies that are not
intended to be subjected to frequent light exposure.
In addition to the characterization of films with respect to their expected storage life, vesicular films are also
separated into two classes (A and B) which are dependent upon their intended use. Class A films are those which
retain density in both the visual and actinic region (printing) after storage. Such films can be viewed directly or
reprinted onto ultraviolet (UV)-sensitive materials. However, some vesicular films are not intended to be reprinted
onto UV-sensitive materials and require only visual capabilities after storage. Such films are designated as Class B
films. Obviously, both Class A and Class B films can faIl into the LE-10 and LE-100 categories. The requirements
for Class A and Class B films are identical, with the exception of image-stability tests after dark-ageing and after
light-fading.
Everyone concerned with the preservation of records on photographic film should realize that specifying the
chemical and physical characteristics of the material does not, by itself, assure satisfactory behaviour. It is also
essential to provide the correct storage temperature and humidity, as well as protection from the hazards of fire,
water, light and certain atmospheric pollutants. Conditions for the storage of record films are specified in ISO 18902
and ISO 18911.
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