ISO 9718:1991
(Main)Photography — Processed vesicular photographic film — Specifications for stability
Photography — Processed vesicular photographic film — Specifications for stability
Photographie — Film photographique vésiculaire traité — Prescriptions pour assurer la stabilité
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Standards Content (Sample)
I NTE R NAT1 ON AL
STANDARD
First edition
1991 -02-15
Photography - Processed vesicular
photographic film - Specifications for stability
Photographie - Film photographique vésiculaire traité - Prescriptions pour assurer
la stabilité
Reference number
IS0 9718 : 1991 (E)
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IS0 9718 : 1991 (E)
Contents page
Foreword . iii
Introduction . iv
1 Scope . 1
2 Normative references . 1
3 Definitions . 1
4 Physical requirements . 2
5 image requirements . 3
6 Accelerated ageing . 3
7 Physical test methods . 4
8 Imagetestmethods . 6
9 Classification for reporting . 7
Annexes
A Microfilm image quality . 8
B Distinction between film storage copies and work copies . 10
C Effects of heat and pressure . 11
D Effect of high humidity . 12
E Light fading of vesicular images . 13
F Corrosiveness . 14
G Bibliography . 15
O IS0 1991
All rights reserved . No part of this publication may be reproduced or utilized in any form or by any
means. electronic or mechanical. including photocopying and microfilm. without permission in
writing from the publisher .
international Organization for Standardization
Case postale !% 0 CH-I21 1 Genève 20 0 Switzerland
Printed in Switzerland
ii
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Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 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, govern-
mental and non-governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission (IEC) on all
matters of electrotechnical standardization.
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.
International Standard IS0 9718 was prepared by Technical Committee ISO/TC 42,
Photography.
Annexes A to G of this International Standard are for information only.
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IS0 9718 : 1991 (E)
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 enter-
prises, has been stimulated by a recognition of the resultant economies in storage
space, organization, accessibility, and ease of reproduction. The safe-keeping of pic-
torial film records having legal, scientific, industrial, medical, historical, military, or
other values has also become increasingly important.
The use of film for records having a long-term value necessitated the development of
International Standards to specify the characteristics of film suitable for this purpose,
and IS0 4331 and IS0 4332 have been written specifiying the requirements for silver-
gelatin films which have archival keeping qualities. Archival films have been defined as
those suitable for the preservation of records having permanent value. To date, only
silver-gelatin type film has been specified as meeting the requirements for archival
records.
However, many users of photographic film are not interested in permanence but in film
usability after extended periods of time. Accordingly, two additional film categories
have been defined : "medium-term" and "long-term" film. The establishment of these
two additional categories increases the utility of International Standards to a wider
spectrum of interested users. IS0 8225 has been written incorporating these
categories in a specification for diazo photographic film.
Criteria for properties of medium-term and long-term vesicular films are based upon
the dark-ageing stability of D,i, processed areas. Different dark-incubation tests are
specified for medium-term and long-term film but all other properties and processing
requirements are identical.
In addition to tests ensuring that the density of Dmi, areas does not increase to unac-
ceptable levels during storage, 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. [Is2] However, to give con-
fidence of acceptable image stability, the permissible density change was made very
small, within the measurement error of the densitometer. Both medium-term and long-
term vesicular films must 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 6). The light-fading tests in this International
Standard ensure satisfactory behaviour for storage copies which 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 classifications which are dependent upon
their intended use. Class A films are those which must have density in both the visual
and the actinic regions after storage. Such films can be viewed directly or reprinted
iv
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IS0 9718 : 1991 (E)
on to ultraviolet (UV)-sensitive materials. However, some films are manufactured
which are not intended to be reprinted on to UV-sensitive materials. Such films require
B films.
only visual capabilities after storage and these are designated as Class
Obviously, both Class A and Class B films can fall into the medium-term and long-term
categories. The properties and processing requirements for Class A and Class B films
are identical, with the exception of change in the D,i, area after dark incubation 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 proper
storage temperature and humidity and protection from the hazards of fire, water, light
and certain atmospheric pollutants. Conditions for the storage of record films are
specified in IS0 5466.
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IS0 9718 : 1991 (E)
l INTERNATIONAL STANDARD
I
L
Photography - Processed vesicular photographic film -
Specifications for stability
IS0 5-1 : 1984, Photography - Density measurements -
1 Scope
Part ?: Terms, symbols and notations.
1.1 This International Standard specifies requirements for
IS0 5-2 : 1985, Photography - Density measurements -
stability of safety polyester base photographic films which have
Part 2: Geometric conditions for transmission density.
a heat-processed vesicular photographic image formed by
0 nitrogen bubbles.
IS0 5-3 : 1984, Photography - Density measurements -
Part 3: Spectral conditions.
1.2 The photographic films covered by this International
I
IS0 1184 : 1983, Plastics - Determination of tensile properties
1
Standard are those intended for medium-term and long-term
of films.
I records.
IS0 4331 : 1986, Photography - Processed photographic
black-and-white film for archival records - Silver-gelatin type
1.3 This International Standard applies to photographic film
on cellulose ester base - Specifications.
in which the image layer is a discrete layer attached to a
transparent support.
IS0 4332 : 1986, Photography - Processed photographic
black-and-white film for archival records - Silver-gelatin type
This International Standard applies to roll film and sheet on polyfeth ylene terephthalate) base - Specifications.
1.4
film.
IS0 5466 : 1986, Photography - Processed safety
photographic film - Storage practices.
1.5 This International Standard characterizes only the
inherent keeping behaviour of the film covered. However, the
IS0 6077 : 1980, Photography - Determination of brittleness
suitability of a film record after extended storage depends on
of photographic film - Wedge brittleness test.
both the inherent ageing characteristics of the film and the
original image qualit;. The latter is discussed in annex A.
IS0 7830 : 1983, Photography - Safety photographic films
e
- Material specifications.
other than motion picture films
1.6 This International Standard applies only to photographic
IS0 8225 : 1987, Photography - Ammonia processed diazo
vesicular film intended and used as medium-term and long-
photographic film - Specification for stability.
term storage copies. It does not apply to vesicular film records
intended and used as "work" or "use" copies as discussed in
annex B. Most film records used in libraries are work copies
and must be durable. Medium-term and long-term storage
3 Definitions
copies must be stored in accordance with IS0 5466. The
effects of heat and pressure are discussed in annex C and of
high humidity in annex D.
For the purposes of this International Standard, the fol1 Ming
definitions apply.
2 Normative references
3.1 medium-term film: A photographic film which is
suitable for the preservation of records for a minimum of
10 years when stored under "medium-term" conditions, pro-
The following standards contain provisions which, through
vided that the original images are of suitable quality.
reference in this text, constitute provisions of this International
Standard. At the time of publication, the editions indicated
were valid. All standards are subject to revision, and parties to
agreements based on this International Standard are encouraged 3.2 long-term film: A photographic film which is suitable
to' investigate the possibility of applying the most recent for the preservation of records for a minimum of 100 years
when stored under "optimum" conditions, provided that the
editions of the standards indicated below. Members of IEC and
IS0 maintain registers of currently valid International Standards. original images are of suitable quality.
1
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IS0 9718 : 1991 (E)
I
For motion-picture applications, the nominal half-angle is I
3.3 archival film: A photographic film which is suitable for
the preservation of records having permanent value when 18,2O, which corresponds to an f-number of fl1,6 and
stored under "optimum" conditions, provided that the original simulates a projector.
images are of suitable quality.
I
NOTE - At present, only silver-gelatin films as specified in IS0 4331
4 Physical requirements
and IS0 4332 are approved for archival records.
4.1 Film base type
Class A films: Films which are usable both visually and
3.4
for printing on to ultraviolet-sensitive materials.
The base used for vesicular film shall be safety poly(ethy1ene I
terephthalate) type and can be identified by the method
3.5 Class B films: Films which are usable visually but do not
specified in 7.1.
have any density requirements for printing on to ultraviolet-
sensitive materials.
4.2 Viscosity retention
3.6 film base: The plastic support for the image layers.
The relative viscosity of a solution of film base obtained from
processed film shall not show a loss which exceeds 5 % as the
3.7 safety poly(ethylene terephthalate) base: A film base
result of accelerated ageing of the processed film. The
composed mainly of a polymer of ethylene glycol and
accelerated ageing shall be accomplished as specified in 6.2
*
terephthalic acid.
and the viscosity determined as specified in 7.2.
3.8 safety photographic film: Film that meets the
4.3 Safety characteristics
specifications with respect to hazard from fire as defined in
IS0 7830.
The film shall meet the requirements of IS0 7830.
3.9 medium-term storage conditions: Those storage con-
4.4 Base physical property loss
ditions suitable for ensuring a minimum useful life of 10 years
for medium-term films.
Processed film shall have a tensile strength and elongation at
1 of table 1 when tested as specified in
break as specified in line
3.10 optimum storage conditions: Those storage con-
7.3. The loss in tensile properties after accelerated ageing, as
ditions suitable for the preservation of photographic film having
specified in 6.2, shall not exceed the percentage specified in
permanent value.
line 2 of table 1.
NOTE - Optimum storage conditions will prolong the useful life of
both archival and non-archival films.
Table 1 - Limits for tensile properties and tensile
properties loss of poly(ethy1ene terephthalate) base film
3.1 1 transmission density: The radiant energy absorbing
Tensile
quality of a photographic image. It is expressed as the
Characteristic strength Elongation
Co-logarithm of the transmittance factor determined for
I I at break I at break I
specified geometric and spectral conditions (see IS0 5).
I 1 Unheated film I I I
Minimum permissible
3.12 visual transmission density : A density measurement
tensile properties 138 MPa*) 75 %
meeting spectral requirements specified in IS0 5-3 for visual
density. It is necessary also to describe the geometric con- 2 Film after accelerated
ageing
ditions of measurement to be specific.
Maximum permissible loss
in tensile properties 10 % -1 10 %
3.13 printing transmission density: A density measure-
ment of a spectrally non-selective film which will produce the
same response on the print material as the film measured (see
IS0 5-3). The contact printing density of a film specimen is
equal to the transmission density of a spectrally non-sensitive
modulator when they both produce the same response on the
4.5 Layer adhesion
print material when contact printed together.
4.5.1 Tape-stripping emulsion adhesion
3.14 projection density: A density measurement in which
the angular distributions of the incident and transmitted radiant
There shall be no removal of the processed image layer when
flux are equal and specified.
the film is tested before and after accelerated ageing. The
For microfilm applications, the angular distribution is a nominal
accelerated ageing shall be accomplished as specified in 6.2,
half-angle of 6,4O, which corresponds to an f-number of ff4,5 and the tape stripping test shall be performed as specified
and simulates a microfilm reader. in 7.4.
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ISQ 9718 : 1991 (E)
4.5.2 Humidity-cycling emulsion adhesion
Table 2 - Limits for image density change after light
The processed image layer shall show no separation or cracking fading test (see 8-41')
which would impair its intended use when tested as specified
Printing Projection
in 7.5.
Vesicular density levels
density density
Original levels
4.6 Blocking
d 0,4 d 0,4
4ow
Processed film shall show no evidence of blocking (sticking),
> 0,8 > 1.4
AD = (Dhigh - Diow)
delamination, or surface damage when tested before and after
Final levels2)
accelerated ageing, as specified in 6.2. Blocking shall be tested
d 0,7 c; 0,7
as specified in 7.6. DI,,
> 0,8 > 1,4
AD = (Dhigh - Diow)
A slight sticking of the film specimens which does not result in
physical damage or a change in the gloss of the surface shall be
acceptable.
4.7 Binder stability
Processed and imaged film shall not exceed a 1 mm increase in
brittleness after accelerated ageing, as specified in 6.2. Brittle-
ness shall be determined at 50 % relative humidity in accord-
5.4 Image stability - Dark ageing of minimum
ance with IS0 6077. Films shall be tested preferably in low-
density areas. density area
Minimum density patches of the processed film shall be
4.8 Thermal sticking
incubated as specified in 8.5 using the two conditions specified
for either medium-term or long-term films. After incubation at
Processed film shall show no evidence of blocking (sticking),
each of the two conditions, the low printing and projection
delamination or surface damage at high temperature when
density patches shall be 0,6 or less. These density requirements
tested before and after accelerated ageing, as specified in 6.2.
shall apply to both projection and printing densities for Class A
Thermal sticking shall be tested as specified in 7.7.
films and to projection density only for Class B films.
A slight sticking of film to glass which does not result in
physical damage shall be acceptable.
5.5 Image stability - Dark ageing of vesicular
image
5 Image requirements
A density patch having a projection density of 2,O shall be
incubated as specified in 8.6. After incubation, the projection
density shall not show a density change greater than f 0,03.
5.1 Proper development
This density requirement shall apply for both medium-term and
long-term film.
Processed film shall not show a projection density decrease
greater than 20 % when tested as specified in 8.2.
6 Accelerated ageing
5.2 Residual diazonium salt test
Processed film shall not show a density decrease greater than
6.1 Application
0,l when tested as specified in 8.3.
Processed film shall be subjected to the following accelerated
5.3 Image stability - Light fading ageing conditions when determining whether or not the film
will meet the requirements specified in clause 4 for viscosity
Low-density and high-density patches (see table 2) of the pro- loss, tape-stripping emulsion
retention, base physical property
cessed film shall be tested in a light exposure apparatus as adhesion, blocking, binder stability and thermal sticking.
specified in 8.4. After testing, the low printing and projection
density patch shall be 0,7 or less. The difference between the
6.2 Accelerated ageing conditions
high and low printing density patches shall be 0,8 or greater
and between the high and low projection density patches shall
be 1,4 or greater (see table 2). These denstiy requirements shall Mount the processed test specimens in a sample rack so that
apply to both projection and printing densities for Class A films they are freely exposed to the surrounding air. Place the rack in
and to projection densities only for Class B films (see annex E).
a glass laboratory desiccator jar. Care shall be taken to prevent
The same density requirements shall apply for both medium- contact of the specimens with each other or with the walls of
term and long-term film.
the jar.
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IS0 9718 : 1991 (E)
Heat the jar in a forced-air circulating oven for 72 h at Immerse the flasks containing the dissolved film base in a water
25 OC f 1 OC until temperature equilibrium
100 OC f 2 OC. The atmosphere within the jar shall be main- bath maintained at
tained at 20 % relative humidity. This relative humidity can be has been reached. Add solvent to adjust the volume of the
obtained by keeping a saturated solution of potassium acetate solution to 100 ml, and thoroughly mix the contents. Transfer a
portion of the liquid, by filtration (see note) if necessary, to an
in water in the bottom of the jar.') Care shall be exercised to
ensure that the saturated solution contains an excess of Ostwald pipette or an equally suitable capillary viscometer
undissolved crystals at 100 OC. The undissolved crystals shall immersed in a constant temperature bath at the same tem-
be completely covered by the saturated solution and the sur- peratu re.
face area of the solution should be as large as practical.
NOTE - Filtration must be rapid to avoid solvent loss. This may be
Maintain the jar and the salt solution at 100 OC for at least 20 h accomplished by filtering through a porous glass-wool pad.
prior to use, to ensure adequate equilibrium.
WARNING - Solutions must not be drawn into pipettes
Alternatively, exposure to these conditions of temperature and
by mouth. Use vacuum or water pumps.
humidity may be provided by means of a conditioning air
cabinet. The specimens shall be suspended to keep them
The pipette chosen shall have a flow time between 70 s and
separated from each other. The air cabinet shall be controlled
110 s for the solvent. The volume taken shall be sufficient to
to (20 f 2) % relative humidity. No other materials shall be in
half-fill the lower bulb of the pipette. Measure the time of flow
the same environment as the specimens during the heating
of the solution through the capillary of the pipette to the
period.
nearest 0,2 s. Repeat the measurement for the same volume of
the pure solvent. Make three readings for each portion. The
Specimens subjected to these accelerated ageing conditions
relative viscosity is the ratio of the average flow time of the
are hereafter designated "heated specimens".
solution to that of the solvent. Duplicate determinations shall
be made on both the unheated and heated specimens and the
averages shall be calculated separately.
7 Physical test methods
7.3 Base physical property loss
7.1 Identification of film base
Remove all emulsion, backing and sublayers from a specimen
7.3.1 Specimen preparation
of the unknown film by scraping. Prepare a sample of the base
material by scuffing the surface with a suitable tool to produce
a very fine powder. Mix this powder in a mortar with about Processed film in 16 mm form may be tested in this width.
100 times its mass of potassium bromide previously ground to Films in other sizes shall be cut 15 mm to 16 mm wide and at
about 200 mesh. Prepare a strip or Obtain an infra-red least 120 mm long, using a sharp tool which does not nick the
absorption curve from this pellet by means of an infra-red edges of the sample. Ten specimens are required for unheated
absorption spectrometer. Establish the identity of the unknown film and ten specimens for film heated as specified in 6.2. The
base by comparison with curves for known polymers. [41 unheated and heated specimens shall be cut alternately and
continuously from a single piece of film.
7.2 Relative viscosity test
7.3.2 Conditioning
Measurements shall be made on the base of two unheated
specimens of processed film and two samples that were sub-
Condition all specimens, both unheated and heated, at
jected to accelerated ageing as specified in 6.2. Remove the
23 OC f 2 OC and (50 f 2) % relative humidity for at least
emulsion and any backing layers by scraping before proceeding
15 h. This may be accomplished by means of an air-conditioned
with the relative viscosity determination. The samples of base
room or a conditioning air cabinet. The specimens shall be sup-
without coatings shall have a mass of 1,00 g each.
ported in such a way as to permit free circulaiton of air around
the film, and the linear air velocity shall be at least 15 cmls.
Dissolve the film base in approximately 95 ml of a mixture of
60 % (rnlrn) phenol and 40 % (rnlm) chlorobenzene.
7.3.3 Procedure
WARNING - The mixture of phenol and chlorobenzene
should be prepared by stirring the molten phenol into the
The film specimens shall not be removed from the conditioning
chlorobenzene. This mixture may be rapidly absorbed
atmosphere for testing. Test the unheated and heated
through the skin and can cause severe burns. In case of
specimens alternately, and calculate the averages separately.
contact, wash the area with water for at least 15 min.
Solvent mixture should be used only with adequate ven-
Determine the tensile strength and percentage elongation at
tilation and hot solutions should be used only in a hood.
break as specified in IS0 1184. Measure the thickness of each
The base may be dissolved by repeated shaking or stirring for 0,002 mm and the width to the nearest
specimen to the nearest
30 min in an oil bath at 140 OC f 1 OC. 0,l mm.
1) The relative humidity is based on the nominal vapour pressure of the salt solution but the relative humidity tolerances cannot be specified.
4
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IS0 9718 : 1991 (E)
7.4 Tape-stripping adhesion test atmosphere. Place the jar for 8 h in a forced-air circulating oven
maintained at 50 OC f 2 OC. The atmosphere within the jar
shall be maintained at 96 % relative humidity, which can be
7.4.1 Specimen preparation
obtained by keeping a saturated solution of potassium sulphate
in water[51 in the bottom of the jar.’) After 8 h, place the rack
Although the dimensions of the processed film specimen are
for 16 h in a second desiccator jar in the same oven. The
not critical, one dimension shall be approximately 150 mm.
atmosphere within this second jar shall be maintained at 11 %
Measurements shall be made on two specimens of unheated,
relative humidity, which can be obtained by keeping a saturated
processed film and on two heated specimens.
solution of lithium chloride in waterc5] in the bottom of the jar.’)
The precautions specified in 6.2 shall be taken to ensure that
the proper humidity is obtained.
7.4.2 Conditioning
Times of 8 h at the high humidity and 16 h at the low humidity
Condition specimens as specified in 7.3.2.
shall constitute one cycle.
7.4.3 Procedure
NOTE 1 - This can be most easily accomplished by placing the
96 % relative humidity jar in the morning and the
specimens in the
11 YO relative humidity jar in the evening.
7.4.3.1 The film specimens shall not be removed from the
conditioning atmosphere for testing.
During a weekend interruption in the cycling procedure, the
film shall be kept at 50 OC f 2 OC and 11 % relative humidity.
Apply a strip of pressure-sensitive, plastic-base, adhesive tape
150 mm long to the image surface of the processed film.
about
Subject the film to 12 humidity cycles, then remove it from the
Press the tape down with thumb pressure to ensure adequate
rack and examine the image for peeling, flaking or cracking.
contact, leaving enough tape at one end to grasp. No portion
of the tape shall extend beyond the edges of the film or cover
NOTE 2 - Films may sometimes exhibit small pinholes in the image
areas of the film perforations.
processing. These can be caused by dirt or dust particles on the sur-
face at the time raw film is exposed and should not be confused with
While holding the film firmly on a flat surface, rapidly remove
holes or cracks in the image layer. The existence of such pinholes in the
the tape from the film surface be peeling the tape back on itself
image prior to humidity cycling should be noted so that their presence
and pulling the end so that it is removed from the film at an
does not lead to false interpretation of an adhesion weakness.
angle of approximately 180O. Removal by the tape of any
portion of the surface layer on any of the specimens shall be
Examine the film under the same magnification and lighting
considered as failure.
conditions as normal for the end use of the product.
7.4.3.2 The results of the tape-stripping test may be very
7.6 Blocking test
dependent upon the adhesive tape used if the bonding force
between it and the particular film surface under test is not suf-
ficiently high. For this reason, a minimum bonding force of 4 N
7.6.1 Specimen preparation
per centimetre of tape width is required.
At least five specimens of processed film shall be conditioned
Determine the bonding force by applying the adhesive tape to
to 62 % relative humidity at 40 OC f 2 OC. A specimen size of
the film surface, in the same manner as specified in 7.4.3.1, and
50 mm square is convenient where the size of the film permits,
peeling it back rapidly from the film surface at an angle of
but the dimensions are not critical provided that all specimens
approximately 180O. Measure the peel-back force required to
are of uniform size.
separate the tape from the film by use of a strain gauge or
maximum-reading spring scale.
7.6.2 Procedure
7.5 Humidity-cycling adhesion test
Place the specimens in a glass laboratory desiccator jar so that
they are freely exposed to the required conditioning at-
mosphere for at least 15 h. Place the jar containing the
7.5.1 Specimen preparation
specimens in a forced-air circulating oven at 40 OC f 2 OC and
about 62 % relative humidity. A relative humidity of approxi-
A specimen 50 mm square or 50 mm by the film width is con-
mately 62 % can be obtained by keeping a saturated solution of
venient, but the dimensions are not critical. Two specimens of
sodium nitrite161 in water in the bottom of the jar.’) The pre-
processed film shall be selected from a high-density area.
cautions specified in 6.2 shall be taken to ensure that the proper
...
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