ISO 18922:2003

INTERNATIONAL ISO
STANDARD 18922
First edition
2003-05-01
Imaging materials — Processed
photographic films — Methods for
determining scratch resistance
Matériaux pour image — Films photographiques développés —
Méthodes de détermination de la résistance à la rayure

Reference number
©
ISO 2003
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Contents Page
1 Scope . 1
2 Normative references . 1
3 Method A . 1
3.1 Apparatus . 1
3.2 Specimen preparation . 2
3.3 Procedure . 2
3.4 Rating . 4
3.5 Evaluation . 4
3.6 Interpretation . 4
3.7 Test report . 5
4 Method B . 5
4.1 Apparatus . 5
4.2 Specimen preparation . 5
4.3 Procedure . 6
4.4 Test report . 6
Annexes
Annex A (informative) Numbering system for related International Standards . 7
Annex B (informative) Validity of test methods . 9
Bibliography . 11
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ISO 2003 – All rights reserved iii

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 18922 was prepared by Technical Committee ISO/TC 42, Photography.
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 18 900 to 18 999 (see Annex A).
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iv ISO 2003 – All rights reserved

Introduction
Processed photographic film should have sufficient scratch or abrasion resistance to permit satisfactory
performance when it is used in equipment for which it is intended and under conditions likely to be encountered.
Treatments to enhance the scratch resistance of film are commercially available. Test methods are needed to
evaluate the effectiveness of such treatments, as well as to rate the inherent scratch resistance of photographic
film.
Scratch resistance is a complex and abstruse characteristic. Processed photographic film is subjected to
several varieties of scratch, such as those caused by grit particles or by cinching in rolls. Since each variety has
a different physical mechanism, scratch resistance of film is not an absolute, singular property. One film may be
rated superior to another in one test, while the opposite ranking may be found in another test. There is not a
scratch or abrasion test capable of ranking a variety of film types as they would behave under different practical
conditions. The test methods described in this document yield results that correlate rather successfully with
practical use in some applications, but not in all.
The scratch resistance of photographic film is affected by relative humidity, processing conditions and surface
friction. This means that scratch tests on photographic film are to be carried out in a controlled atmosphere with
proper processing and without touching of the film surface or other handling that might unintentionally lubricate
the surface. In some cases, such as lacquered or freshly processed film, the scratch resistance may change
with age. Lubrication generally increases the scratch resistance of a film surface. Lubrication can be detected
by the method described in ISO 18904.
Both the emulsion layer and the base side of processed photographic film are susceptible to scratching or
abrasion. However, many film-handling machines are designed to protect the emulsion side as much as
possible, so that the base side takes the brunt of the wear. The test methods given in this document are
applicable to both sides of the film.
Scratch resistance greatly depends upon the geometry of the stylus used in the test. Styli that are nominally the
same may differ widely in scratch characteristics. For this reason, the methods described in this International
Standard are good for material comparisons using a single stylus point. However, agreement of scratch levels
obtained with different equipment may be poor.
Unprocessed photographic emulsions generally exhibit photographic scratch or abrasion sensitivity (made
visible by development) at lower levels than those where physical scratch is apparent. Method A (see Clause 3)
can be used to determine photographic abrasion sensitivity, if desired; the test should be performed in the dark,
and the specimen should then be processed.
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ISO 2003 – All rights reserved v

.
vi
INTERNATIONAL STANDARD ISO 18922:2003(E)
Imaging materials — Processed photographic films — Methods
for determining scratch resistance
1Scope
This International Standard is applicable to evaluating the scratch resistance of dry, processed photographic
film. It specifies two test methods for evaluating the scratch resistance on either the emulsion or the base side.
The two test methods usually give comparable results. It provides empirical laboratory tests made under
controlled conditions, but does not necessarily predict the actual scratch resistance of a film in any particular
commercial machine.
Method A (see Clause 3) gives a measure of the minimum load requirement to produce a scratch, requires less
elaborate evaluation equipment and is less stringent in its requirements of the optical condition of the
specimens. Method B (see Clause 4) provides a measurement of haze produced by various stylus loads, is a
more complete measure of scratch characteristics of a material and is the preferred method.
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.
ANSI/ASTM D1003-95, Test method for haze and luminous transmittance of transparent plastics
3MethodA
3.1 Apparatus
The apparatus shall consist of a specimen holder that will hold the specimen flat on a smooth glass plate. The
specimen holder should permit smooth, linear, horizontal travel of the specimen for a distance of at least 20 mm
without sidewise motion, and the holder may be either manually operated or power driven.
1)
A spherical sapphire stylus of either 0,050 mm or 0,075 mm radius shall be used . It shall be mounted at the
end of a pivoted arm, so that it can be lowered onto the specimen and thereby scribe a line on it when the
specimen holder travels along under the stylus. The stylus shall make perpendicular contact with the specimen.
The stylus arm may be pivoted on a threaded hinge with a knurled knob or other provision for positioning the
stylus laterally so that many parallel scribe lines can be made on the same specimen. Alternatively, the
specimen holder can be provided with lateral positioning and a simple pivot used on the stylus arm.
1) Sapphire styli generally give results that usually reflect trade experience. They may be obtained from the following
sources: Stanton, Inc., 101 Sunnyside Blvd., Plainview, NY 11803, USA; Carbide Probes, Inc., 1328 Research Park Dr.,
Dayton, OH 45432, USA; Sinto Kagaku, Co., Ltd., Nukui 2-16-30, Nerina, Tokyo 176, Japan. This information is given for
the convenience of users of this International Standard and does not constitute an endorsement by ISO of these suppliers.
Diamond styli have the advantage of greater durability, but because of their different friction properties they are frequently
less sensitive to differences between materials.
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ISO 2003 – All rights reserved 1

The stylus arm shall be counterbalanced so that it produces no load on the stylus. The weights shall be
designed so that, when used singly or in combination, the centre of gravity of the mass will be positioned directly
over the stylus. Preferably, this should provide for automatic, accurate positioning. These weights should range
from 1 g to 100 g, but are not necessarily limited to this range.
An example of a scratch test instrument is shown in Figure 1. Figure 2 shows a mechanical drawing of the same
apparatus. Exact dimensions are not critical, except with respect to the stylus.
NOTE The test apparatus for mushiness, described in ISO 18914, may be adapted for this test which is constructed so that
the load is continuously increased as the stylus arm is drawn across the specimen. However, it is not as satisfactory since
only a single point, rather than a line, is obtained at each load level.
Key
1hinge
2 knob
3 pivoted arm
4stylus
5 specimen holder
6 aperture
Figure 1 — Spherical stylus scratch tester
3.2 Specimen preparation
Film specimens should preferably be processed so that there is no significant optical density. Film exposed with
an image that contains some clear areas is also usable. Film shall be processed in the normal manner for the
specific product, except where the effect of processing variables is being investigated.
NOTE Some optical density, up to 0,7, can be tolerated with only a minor effect on the results. However, it is best to avoid
density entirely when possible.
Care shall be taken in handling specimens to avoid fingerprints. Use of “medicated” cotton gloves, or any other
practice that might contaminate the film surface shall be avoided.
Film shall be conditioned in individual strip format for at least 2h at the relative humidity (RH) at which the test
will be conducted. During the conditioning operation, there shall be no handling of the test surface.
3.3 Procedure
◦
A temperature of 23C5 and a relative humidity of 0% are suggested test conditions. However, other relative
humidities, such as 15 % RH and 70 % RH, may prove useful.
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2 ISO 2003 – All rights reserved

Key
1hinge
2knob
3 pivoted arm
4stylus
5 specimen holder
6 aperture
Figure 2 — Const
...