ISO/TR 12031:2000

.
TECHNICAL ISO/TR
REPORT 12031
First edition
2000-04-01
Micrographics — Inspection of silver-
gelatin microforms for evidence of
deterioration
Micrographie — Inspection des microformes en argent-gélatine pour mise
en évidence de détérioration
Reference number
©
ISO 2000
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ii © ISO 2000 – All rights reserved

Contents Page
Foreword.v
Introduction.vi
1 Scope .1
2 References.1
3 Terms and definitions .1
4 Inspection conditions.2
5 Equipment and supplies .2
5.1 General.2
5.2 Light box and film rewinds for 16 mm and 35 mm film.2
5.3 Eye loupe (eye glass) .2
5.4 Microscope.2
5.5 Specular light source .2
5.6 Black velvet .2
5.7 Inspection gloves.2
6 Sampling method.3
6.1 General.3
6.2 Division into survey groups .3
7 Inspection procedures .3
7.1 General.3
7.2 Procedure for all microforms .3
7.3 Checks for all microforms .3
7.4 Additional checks for roll film .4
7.5 Additional checks for jackets.4
7.6 Additional checks for aperture cards .4
8 Inspection reporting .4
8.1 Classification.4
8.2 Data collection, general .5
8.3 History and description of group or collection .5
8.4 Individual microform inspection report.6
8.5 Data analysis (optional) .6
9 Types of defects.7
9.1 General.7
9.2 Microbiological growths .7
9.3 Redox blemishes .8
9.4 Residual processing chemicals .8
9.5 Emulsion adhesion .9
9.6 Separation of the emulsion from the film base.9
9.7 Brittleness.9
9.8 Base shrinkage .9
10 Remedial action .9
10.1 General.9
10.2 Subsequent re-inspections.10
Annex A Determination of base type .11
Annex B Factors affecting deterioration .12
B.1 General.12
B.2 Inappropriate choice of film material.12
B.3 Processing.12
B.3.1 Improper fixing.12
B.3.2 Improper washing .12
B.3.3 Insufficient drying.12
B.4 Improper climatic conditions during storage .12
Annex C Examples of types of defects.13
C.1 Microbiological growths.13
C.2 Redox blemishes .14
C.2.1 Exposed leader .15
C.2.2 Silver sheen.15
C.3 Separation of the emulsion from the film base.16
iv © ISO 2000 – All rights reserved

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.
In exceptional circumstances, when a technical committee has collected data of a different kind from that which is
normally published as an International Standard ("state of the art", for example), it may decide by a simple majority
vote of its participating members to publish a Technical Report. A Technical Report is entirely informative in nature
and does not have to be reviewed until the data it provides are considered to be no longer valid or useful.
Attention is drawn to the possibility that some of the elements of this Technical Report may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TR 12031 was prepared by Technical Committee ISO/TC 171, Document imaging applications, Subcommittee
SC 1, Quality.
Introduction
The purpose of this Technical Report is to provide a uniform method of selecting and inspecting silver-gelatin
microforms for evidence of deterioration. Improper processing, handling, and storage conditions have long been
known to promote biological attack and various other kinds of image degradation. Examination of some large
collections of microfilmed records within the last decade has revealed a number of instances of spot blemishes.
This may be influenced by the number of years and by the number of different processing conditions used. These
instances serve to focus attention on the fact that, although film may be processed and stored in the best available
conditions, the only assurance that such records are being well maintained is a systematic programme of careful
inspection. Silver-gelatin microforms which have been manufactured, exposed, developed, and stored according to
existing standards and which have a long life expectancy may not require extensive inspection.
vi © ISO 2000 – All rights reserved

TECHNICAL REPORT ISO/TR 12031:2000(E)
Micrographics — Inspection of silver-gelatin microforms for
evidence of deterioration
1 Scope
This Technical Report applies to all forms of silver-gelatin microfilm, whether in roll, aperture card, jacket or
microfiche format. It describes the equipment and procedures necessary to identify and monitor deterioration. This
information serves to identify the extent and nature of the problem and will ultimately provide a sound basis for any
remedial action that may be required.
2 References
ISO 417:1993, Photography — Determination of residual thiosulfate and other related chemicals in processed
photographic materials — Methods using iodine-amylose, methylene blue and silver sulfide.
ISO 543:1990, Photography — Photographic films — Specifications for safety film.
ISO 2859-0:1995, Sampling procedures for inspection by attributes — Part 0: Introduction to ISO 2895 attribute
sampling system.
ISO 2859-1:1999, Sampling procedures for inspection by attributes — Part 1: Sampling plans indexed by
acceptable quality level (AQL) for lot-by-lot inspection.
ISO 2859-2:1985, Sampling procedures for inspection by attributes — Part 2: Sampling plans indexed by limiting
quality (LQ) for isolated inspection.
ISO 2859-3:1991, Sampling procedures for inspection by attributes — Part 3: Skip-lot sampling procedures.
ISO 5466:1996, Photography — Processed safety photographic film — Storage practices.
ISO 6196-1:1980, Micrographics — Vocabulary — Part 01: General terms.
ISO 10602:1995, Photography — Processed silver-gelatin type black-and-white films — Specifications for stability.
3 Terms and definitions
For the purpose of this Technical Report, the terms and definitions given in ISO 6196-1 and the following apply.
3.1
frilling
separation of the emulsion from the film base during initial processing
4 Inspection conditions
The inspection room or location selected for inspection should be clean with a relatively dust-free atmosphere and
the temperature should not exceed 23 °C and relative humidity should not exceed 50 %. The work-top area should
be clean and free of objects and substances that might damage the microfilm.
Changes in temperature and/or humidity during inspection or during transportation from the film storage facility to
inspection room should be avoided.
5 Equipment and supplies
5.1 General
The inspection equipment should be such that the film cannot be damaged during the inspection process.
5.2 Light box and film rewinds for 16 mm and 35 mm film
Light boxes of this nature usually are equipped with a light source covered by translucent glass or plastic.
Fluorescent lights can be used to minimize the heat build-up of the inspection station. Tungsten or tungsten-
halogen lights can also be used.
5.3 Eye loupe (eye glass)
Two eye loupes with magnification of approximately 5� and 15� should be used. The lower magnification will
provide a wider field of view, while the higher magnification will allow much closer inspection of specific defects.
5.4 Microscope
A microscope with a magnification capability of at least 25� and 50� will be required for occasional close
examination. A fairly intense substage illuminator is essential to penetrate the high density areas of the leader and
trailer. A microscope having a surface illuminator may be helpful in evaluating surface characteristics. A camera to
take photomicrographs of the defects may be helpful to record progression of any deterioration of the microfilm.
5.5 Specular light source
Another light source other than room ambient light should be available to inspect the film surface with and without
magnification for image degradation, scratches and other defects. This light source is necessary for microfiche,
jackets, aperture cards and roll film.
5.6 Black velvet
Placing a swatch of black velvet behind the film may be of help for detecting scratches, water spots, and abrasions.
5.7 Inspection gloves
Clean, lint-free white cotton or nylon gloves should be worn to avoid marking the film with fingerprints. These
gloves should be used exclusively for this purpose. It is highly recommended that the gloves be changed regularly.
2 © ISO 2000 – All rights reserved

6 Sampling method
6.1 General
It is preferable that each film be inspected. If this is not possible, a suitable sampling procedure as given in
ISO 2859 should be used to provide representative data of the total population of the group or lot sample.
6.2 Division into survey groups
The collection should be divided into groups of similar types. Examples of such similarities are groups stored under
the same conditions; similar film sizes such as 16 mm and 35 mm; similar formats and film types, i.e. jackets,
aperture cards, polyester film, and acetate film; record series type; etc. As most types of deterioration seem to be
progressive with age, some form of separation by date may be significant. In a library or archives setting, an
ongoing collection of newspaper files or a series of books or private papers microfilmed over a specific period of
time could be considered a significant lot or group.
7 Inspection procedures
7.1 General
The microfilm inspector should be thoroughly familiar with the various types of ageing defects as well as defects
normally associated with film processing (see clause 9). The inspector should also be aware that older film should
be treated carefully until it has been established that normal handling will not damage the film.
7.2 Procedure for all microforms
Both sides of the film should be examined.
Rotate film so that the light reflects off the film surface.
Examine the reverse side of the film. Some forms of deterioration can be detected with the unaided eye at this
initial stage.
Some defects are more easily seen over the light boxes, without the aid of an eye loupe, while others need to be
viewed under stronger magnification. Inspection procedures for microforms having higher reduction ratios may
require more critical evaluation.
The inspector should carefully examine the film using both transmitted and reflected light. To detect scratches
inspection should be made through film illuminated from behind and toward black velvet.
7.3 Checks for all microforms
Verify that the base is not cellulose nitrate (see annex A.)
NOTE The base of some older collections may be cellulose nitrate.
Smell the film, the carrier, and inside the container for unusual odours. Check especially for acetic odour with
triacetate base film.
Check the constitution of the film surface, especially for scratches, coverings, fungus, or coating separation.
Check to see if storage containers, such as film boxes, storage cabinets, and other containers, show any signs of
deterioration.
7.4 Additional checks for roll film
Holding the centre of the reel between thumb and index finger, turn the reel with the free hand so that the leader
falls free. If it does not fall free, carefully determine the reason. It is not unusual for film that has not been unwound
for a long time period to stick slightly. If the leader and following coil cannot be freed without damaging the film, the
inspector should consult a film specialist.
Holding the reel in one hand, unwind sufficient leader to examine the black area in the ambient room light for
evidence of a silver sheen on the emulsion side of the film.
Place the roll of film on the rewinds with the emulsion side facing up, and slowly advance the film over the light box.
At approximately every 3 m of film, stop the film to carefully examine the images with the aid of the eye loupe or
microscope, using both transmitted and reflected light for evidence of deterioration on the emulsion side of the film.
Check roll film for possible defective splices due to improper tape or splicing procedures, and for improper material
or adhesives that may cause defects.
7.5 Additional checks for jackets
Examine the carrier in ambient room light. The channel joiners may become separated and consequently unable to
retain the images in the proper channel.
Check the channel for dust and soiling. The channel and film should not stick together; sticking would indicate
improper dryin
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