ISO 18914:2013

Imaging materials - Photographic film and papers - Method for determining the resistance of photographic emulsions to wet abrasion

ISO 18914:2013 specifies a laboratory test method for determining the resistance of photographic emulsions or gelatin backings to abrasion damage during processing. This method may be used to determine the effects of variations in processing solutions, gelatin layer properties, processing solution temperatures and times, or a combination of these factors, on the wet scratch resistance of gelatin layers. This method is applicable to the determination of the physical integrity of photographic emulsions when wet.

Matériaux pour image — Films et papiers photographiques — Méthode de détermination de la résistance des émulsions photographiques à l'abrasion dans des conditions humides

General Information

• Status: Published
• Publication Date: 04-Feb-2013
• ICS: 37.040.20 - Photographic paper, films and plates. Cartridges
• Technical Committee: ISO/TC 42 - Photography
• Drafting Committee: ISO/TC 42/WG 5 - Physical properties and image permanence of photographic materials
• Current Stage: 9093 - International Standard confirmed
• Start Date: 05-Jun-2023
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 18914:2002 - Imaging materials - Photographic film and papers - Method for determining the resistance of photographic emulsions to wet abrasion
• Effective Date: 18-Aug-2012

Overview - ISO 18914:2013 (wet abrasion test for imaging materials)

ISO 18914:2013 defines a laboratory method for determining the resistance of photographic emulsions and gelatin backings to wet abrasion during processing. Commonly called the “mushiness” or wet scratch-resistance test, it measures the force (in grams) at which a stylus digs into a wet emulsion. The standard applies to photographic film and paper emulsions when wet and is intended for controlled comparisons of processing variables, emulsion formulations, ageing effects, and post‑processing treatments.

Keywords: ISO 18914, wet abrasion, photographic emulsions, gelatin layers, scratch resistance, imaging materials

Key topics and technical requirements

• Test scope: Applies only to wet emulsion or gelatin layers (not the support material).
• Specimens: Representative samples, typically 35 mm × ~250 mm; can be unprocessed or processed (clear/D).
• Apparatus:
  • Immersion tray that moves smoothly at least 30 mm horizontally (manual or power driven).
  • Spherical stylus (sapphire or diamond) mounted on a pivoted arm; 0.38 mm radius for film-base emulsions and 0.20 mm radius for paper-base emulsions.
  • Two instrument formats: constant-load (weights from ~1 g to 210 g) and continuous-load (weight increases from 0 g to 70 g over travel; additional weights up to 150 g possible).
• Procedure:
  • Specimen immersed in distilled water or actual processing solution at test temperature.
  • Tray is drawn under the stylus completing travel in 1–2 s; three scratch lines (≥30 mm) per load.
  • For multi-step processing, specimens are pre-immersed sequentially in prior solutions to simulate real processing.
• Rating and interpretation:
  • The wet-abrasion (mushiness) value = grams on the stylus that cause penetration.
  • Ratings may be made by reflected or transmitted light, wet or after drying.
  • Note: results from constant-load and continuous-load instruments may not be directly comparable. Typical significance thresholds are provided (e.g., 5 g below 20 g, 10 g between 40–100 g).

Applications and who uses this standard

• Quality assurance and R&D for photographic film and paper manufacturers to:
  • Compare emulsion formulations and gelatin treatments.
  • Evaluate effects of processing solutions, temperatures, times, and ageing on wet scratch resistance.
• Conservation scientists and photographic labs assessing physical integrity of historical or experimental materials.
• Equipment designers and process engineers optimizing processing lines to reduce abrasion damage.

Related standards

• ISO 18922 - Processed photographic films - Methods for determining dry scratch resistance (referenced for dry testing and related methodology).

This standard is essential when assessing wet mechanical durability of imaging materials and for rigorous, repeatable evaluation of processing and formulation impacts on emulsion integrity.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 18914
Second edition
2013-02-01
Imaging materials — Photographic film
and papers — Method for determining
the resistance of photographic
emulsions to wet abrasion
Matériaux pour image — Films et papiers photographiques —
Méthode de détermination de la résistance des émulsions
photographiques à l’abrasion dans des conditions humides
Reference number
©
ISO 2013
© ISO 2013
All rights reserved. Unless otherwise specified, 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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Apparatus . 1
2.1 Component parts . 1
2.2 Equipment design. 1
3 Specimen preparation . 3
4 Test method . 3
4.1 Procedure . 3
4.2 Rating . 4
4.3 Interpretation . 4
5 Test report . 4
Bibliography . 5
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 18914 was prepared by Technical Committee ISO/TC 42, Photography.
This second edition cancels and replaces the first edition (ISO 18914:2002), of which it constitutes a
minor revision with the following changes:
— the contact information contained in footnote 1 has been updated;
— the original footnotes 2 and 4 have been removed and the remaining footnotes have been reidentified;
— Annex A has been removed.
iv © ISO 2013 – All rights reserved

Introduction
If the gelatin emulsion of photographic materials is rubbed against any stationary part of a processing
machine, it may be damaged by abrasion during processing. Abrasion can also occur when film or paper
is processed in a tray by hand, as the gelatin layers are soft enough to be gouged by foreign particles,
corners, or fingernails.
Photographic emulsions are usually more susceptible to abrasions when wet than when dry. Wet
emulsions and gelatin backing are also more susceptible to abrasion than the support materials. The
test method in this International Standard is applicable only to such wet emulsions or gelatin layers. For
[1]
dry scratch resistance, see in the Bibliography.
Photographic emulsions and gelatin layers show physical changes with time. The resistance of these
layers to wet abrasion depends on the inherent properties built in at manufacture. It also varies with
the treatment received in the dry state prior to processing, such as temperature and moisture content
during storage.
The susceptibility to abrasion during processing depends not only on the inherent characteristics of the
[2]
emulsion, but also on the types of processing solutions, temperatures, and immersion times (see in
the Bibliography for descriptions). In determining emulsion resistance to abrasion, these factors are to
be carefully controlled.
The results of wet abrasion, or mushiness, tests are most significant if consideration is given to the final
usage of the particular material. For instance, some films are viewed while wet, although usually films
and photographic prints are dried prior to viewing or other use. Some materials may show less abrasion
damage when examined after drying than when examined wet. The most appropriate rating method is
to be chosen and clearly stated in the results.
The test method in this International Standard provides an excellent means of comparing emulsions
of different ages, types, processing solutions, processing immersion times, and temperatures, as well
as the effects of post-processing treatments. However, many factors are involved in the equipment and
technique in either continuous, tank, or tray processing which cannot be considered in a test procedure.
Analysis of abrasion resistance in a particular processing system can only be made in the processing
system under consideration.
This test method has also been used to measure the change in the physical integrity of the gelatin-
emulsion layer after normal or accelerated ageing. For this purpose, the wet abrasion (mushiness) is
measured when the emulsion is immersed in distilled water.
INTERNATIONAL STANDARD ISO 18914:2013(E)
Imaging materials — Photographic film and papers —
Method for determining the resistance of photographic
emulsions to wet abrasion
1 Scope
This International Standard specifies a laboratory test method for determining the resistance of
photographic emulsions or gelatin backings to abrasion damage during processing.
This method may be used to determine the effects of variations in processing solutions, gelatin layer
properties, processing solution temperatures and times, or a combination of these factors, on the wet
scratch resistance of gelatin layers.
This method is applicable to the determination of the physical integrity of photographic emulsions when
wet, but it is not applicable to the evaluation of the scratch resistance of the support material.
2 Apparatus
2.1 Component parts
The apparatus shall consist of the following elements:
— a specimen tray in which the specimen can be immersed in either distilled water or a processing
solution. The tray shall be free to move smoothly in a horizontal plane for a distance of at least
30 mm without s
...