ISO 18913:2012

INTERNATIONAL ISO
STANDARD 18913
Second edition
2012-06-01

Imaging materials — Permanence —
Vocabulary
Matériaux pour image — Permanence — Vocabulaire




Reference number
ISO 18913:2012(E)
©
ISO 2012

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ISO 18913:2012(E)

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ISO 18913:2012(E)
Contents Page
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
Bibliography . 22

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ISO 18913:2012(E)
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 18913 was prepared by Technical Committee ISO/TC 42, Photography.
This second edition cancels and replaces the first edition (ISO 18913:2003), which has been technically
revised.
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ISO 18913:2012(E)
Introduction
This International Standard is one of a series dealing with the physical properties and stability of imaging
materials.

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INTERNATIONAL STANDARD ISO 18913:2012(E)

Imaging materials — Permanence — Vocabulary
1 Scope
This International Standard establishes a vocabulary of terms and definitions used in relation to the
permanence of imaging materials, related storage materials and digital storage media.
In most cases these terms and definitions are generic and are applicable to the entire imaging industry. For
terms and definitions specific to particular applications, industry standards are applicable. However, in some
cases the definition of a term is still evolving and/or is used by different user groups in different ways. In these
cases, a definition related to permanence of imaging materials work is given and a note to this effect is
included.
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.
ISO 5-3, Photography and graphic technology— Density measurements — Part 3: Spectral conditions
ISO 10716, Paper board — Determination of alkali reserve
ISO 14644-1, Cleanrooms and associated controlled environments — Part 1: Classification of air cleanliness
by particle concentration
ISO 18902, Imaging materials — Processed imaging materials — Albums, framing and storage materials
ISO 18906, Imaging materials — Photographic films — Specifications for safety film
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
abrasion
wearing away of a surface by friction as a result of rubbing
3.2
absolute humidity
mass of water vapour per unit volume of air
3.3
accelerated ageing
changes in the characteristics of an image-bearing material that occur when one or more of the environmental
factors (such as temperature, light, or air pollutants) is intentionally increased above that found in typical use
or storage conditions, usually to induce change in a shorter period of time
NOTE This is done in order to predict the behaviour of a product under typical storage or display conditions.
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ISO 18913:2012(E)
3.4
accuracy
closeness of the agreement between the result of a measurement and a true value of the measurement
NOTE 1 Accuracy is a qualitative concept.
NOTE 2 The term precision should not be used for accuracy.
3.5
acid-free adhesive
mounting adhesive with a cold extraction pH between 7,0 ± 0,2 and 9,5 ± 0,2, as stipulated in ISO 18902
3.6
acid-free paper or paperboard
paper or paperboard with a cold extraction pH between 7,0 ± 0,2 and 9,5 ± 0,2 that is produced in an acid-free
process and sized in a neutral or alkaline manner, as stipulated in ISO 18902
3.7
album
binder or book structure having front and back covers (usually opaque and rigid) in which pages are bound
along one edge either by plastic straps, gluing, sewing, metal posts or rings
3.8
albumen plate
glass sheet bearing a silver halide/albumen layer which yields a visible image after exposure and processing
3.9
ambient conditions
working environment
NOTE For preservation purposes these may or may not be the same as the storage environment.
3.10
ambrotype plate
glass plate collodion positive, i.e. glass sheet bearing a thin silver halide/cellulose nitrate layer which yields a
visible image after exposure and processing
NOTE The processed negative silver image appears as a positive when backed by a dark field.
3.11
anti-blocking agent
component of a material that provides microscopic bumps on the surface in order to lower contact area,
reduce the coefficient of friction and minimize ferrotyping, blocking and the occurrence of Newton's rings
EXAMPLE Talc, silicates or matte beads.
3.12
aperture card
card of standard dimensions with one or more openings into which a microfilm frame or frames can be
mounted or inserted
3.13
aperture window
opening in the flange that is used to facilitate threading of magnetic tape on the hub and inspection of the wind
3.14
archival (deprecated)
material that can be expected to preserve images forever, so that such images can be retrieved without
significant loss when properly stored
NOTE As no such material exists, this is a deprecated term and as such is not to be used in International Standards
for imaging materials or in systems specifications.
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ISO 18913:2012(E)
3.15
Arrhenius plot
plot of the logarithm of the time for a given change in a characteristic proportional to the reaction rate (dye loss,
tensile strength change, D yellowing, etc.) versus the reciprocal of the temperature expressed in Kelvin
min
NOTE The Arrhenius plot can be used to predict behaviour at a temperature lower than that at which a test is run, as
[1]
described in ISO 18924 .
3.16
base
support in a recording material on which the image receiving/recording layers or magnetic layer (and, if
necessary, the back layer) are coated
3.17
baseline
condition representing a hard copy system (print, optical disc, etc.) at time of manufacture
NOTE This is customarily the initial parameter measurement taken prior to any application of stress. The designation
is usually t = 0 for a stress time equal to zero hours.
3.18
blister
localized delamination of a multilayer assembly that looks like a bubble
3.19
Block Error Rate
BLER
ratio of erroneous blocks to total blocks on an optical disc measured at the input of the first (C1) decoder
(before any error correction is applied)
NOTE The more commonly reported value for BLER is the number of erroneous blocks per second measured at the
input of the C1-decoder during playback at the standard (1X) data rate.
3.20
blocking
sticking together of similar or dissimilar materials in physical contact
cf. anti-blocking agent (3.11)
3.21
blue print
defect resulting from a drastic reduction in the light stability of the yellow dye in a chromogenic print
NOTE A common cause is when a print has been lacquered in a very humid environment or was not thoroughly dried
before lacquering.
3.22
brittleness
property of a material that causes it to crack or break when bent or flexed
3.23
buffered
paper or paperboard with alkali reserve (as defined in ISO 10716) that is equivalent to at least 2,0 % mass
fraction calcium carbonate (CaCO )
3
3.24
can
metal or plastic container for a roll of recording material, such as photographic film or magnetic tape
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ISO 18913:2012(E)
3.25
carrier
medium upon which information is recorded
cf. medium (3.114)
3.26
carton or box
outer container that can hold one or more individual units and which may be a fabrication of paper, card stock
or plastic
3.27
cartridge
housing for a roll of recording material, such as photographic film or magnetic tape, wound on a single hub or
reel
cf. cassette (3.28)
NOTE The term cartridge is also used in some cases to describe an ink container.
3.28
cassette
housing for a roll of recording material, such as photographic film or magnetic tape, whose ends are attached
to two hubs or reels
cf. cartridge (3.27)
3.29
CD-ROM
compact disc read only medium
optical disc to which information is transferred during manufacture to certain areas in the compact disc format
NOTE The information can be read many times.
3.30
CD-RW
compact disc rewritable
recordable optical disc in which information can be recorded to certain areas in the compact disc format
NOTE The information can be erased and rerecorded many times.
3.31
cellulose-acetate base
base for recording materials composed mainly of cellulose esters of acetic acid
3.32
cellulose-ester base
base for recording materials composed mainly of cellulose esters of acetic, propionic or butyric acid, or
mixtures thereof
3.33
class 100 000 clean room
controlled environment in which the level of airborne contaminates meets the requirements of ISO 14644-1
3.34
collodion plate
collodion wet plate
collodion dry plate
glass sheet bearing a thin silver halide/cellulose nitrate layer which yields a visible image after exposure and
processing
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ISO 18913:2012(E)
3.35
colour screen plate
glass sheet bearing a colour screen consisting of dyed elements in contact with a silver halide/gelatine layer
which yields a visible image after exposure and processing
3.36
compact disc
CD
CD-ROM optical disc format on which the information layer is located at one surface of a substrate and the
data can be read by an optical beam
NOTE Described in IEC 60908.
3.37
compact disc-recordable
CD-R
recordable optical disc in which information can be recorded to certain areas in compact disc format
NOTE 1 Information can be recorded one time and read many times.
NOTE 2 The term "compact disc-write once" (CD-WO) has also been used to describe this type of disc.
3.38
conditioning
exposure of a specimen to air at a given relative humidity and temperature until equilibrium is reached
3.39
conservation
examination and analysis, documentation and treatment of library or archive materials, artwork or objects to
stabilize them chemically or strengthen them physically, prolonging their life in the original form
3.40
container
box, can or carton used for storage and shipping of recording materials
EXAMPLE The box into which a reel, cassette, cartridge, disc or shell is placed.
NOTE Reels, cassettes, cartridges or shells are not containers.
3.41
copy
reproduction of the information from a master
3.42
core
metal or plastic cylinder on which recording material is wound
cf. hub (3.84)
3.43
crazing
network of fine cracks on the surface of a print or film usually the result of environmental stresses on the
surface layer
3.44
cupping
departure of film or paper from physical flatness characterized by the condition where the four corners of a
rectangular sheet turn up but the edges do not
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ISO 18913:2012(E)
3.45
curl
departure of film, paper or magnetic tape from physical flatness with the tendency to curve into a cylindrical
shape
3.46
cyan spots
defect that results when the ultraviolet absorber in an older technology chromogenic print crystallizes and
permits the back-scattering of light
3.47
dark stability
ability of a print, negative or transparency to resist fading or staining to ambient environmental factors in the
absence of light
3.48
daylight filter
optical filter or combination of filters that modifies the spectral power distribution of a light source to better
represent some defined daylight spectrum
3.49
delamination
separation of a laminate into its constituent layers
3.50
dew point
temperature at which moisture begins to condense on a surface, corresponding to saturation for a given
absolute humidity
cf. relative humidity (3.163)
EXAMPLE The more humid the air, the higher the dew-point temperature.
3.51
differential dimensional change
difference between the dimensional changes of the material in the two principal directions (length and width)
NOTE Polyester-based films frequently have maximum and minimum dimensional changes in directions other than
the length or width. These can be determined by rotating and viewing the uncoated base between a pair of crossed
polarizers. When the direction corresponding to either the maximum or minimum dimensional change is coincident with
the optical axis of one polarizer, there is minimum light transmission through the base.
3.52
digital print
print where the image is printed from the digital domain
NOTE There is substantial confusion around the definition of this term by users, particularly in the consumer market
where it may be taken to mean a print where the original image is produced or manipulated in the digital domain.
3.53
digital printing media
media used by colour hard copy printers
EXAMPLE Silver halide, thermal dye transfer (“dye sub”), inkjet, electrophotography, paper, plastic, canvas, fabric or
ink receptive materials.
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ISO 18913:2012(E)
3.54
digital versatile disc
DVD
optical disc format in which one or more information layers are located between two substrates and the data
can be read by an optical beam
NOTE Formerly called digital video disc.
3.55
dimensional change
processing permanent dimensional change caused by photographic processing alone
NOTE This can be conventional wet chemical processing, vapour processing or heat processing. The dimensional
change is measured after conditioning at the same relative humidity and temperature as used for the original
measurement and is expressed as a percentage.
3.56
dimensional change
processing and ageing together permanent dimensional change that occurs as a result of processing plus
ageing of the processed material
NOTE It is measured after conditioning of the processed, aged film or paper at the same relative humidity and
temperature as used for the original measurement and is expressed as a percentage.
3.57
dimensional hysteresis
difference in the absolute dimensions of a specimen in equilibrium with air at a given relative humidity, when
conditioned from a higher relative humidity and when conditioned from a lower relative humidity
3.58
duplicate
reproduction of a master, retaining the same polarity and size
3.59
dye diffusion thermal transfer print
D2T2 print
digital print made by the thermally induced transfer of dry colourant from a donor sheet or ribbon to the
surface of a specially coated substrate
NOTE This process is sometimes known as “dye sub”, short for "dye sublimation". This is a misnomer as the dyes
melt to form a liquid which is transferred to the substrate rather than subliming through the vapour phase. The misnomer
arises from a similarity to an earlier textile printing process.
3.60
electrophotographic print
digital print made from electrostatically charged toner particles or droplets
3.61
emulsion layer(s)
image or image-forming layer(s) of silver halide photographic films, papers and plates
3.62
encapsulation
sealing of all edges of a specimen that has been laminated on both front and back surfaces
NOTE Usually done by laminating with sheets that are larger in dimension than the specimen and then sealing at the
overlaps.
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ISO 18913:2012(E)
3.63
encapsulation - irreversible
protective coating applied to both sides of a flat object such as paper or film and sealed at the edges which
cannot be removed
NOTE Use of liquid coatings (liquid laminates) on two sides is not considered a form of encapsulation.
3.64
encapsulation - reversible
protective coating applied to both sides of a flat object such as paper or film and sealed at the edges which
can be removed
3.65
enclosure
folder, envelope, sleeve or clam shell that is intended for physical protection against mechanical damage
3.66
end-of-life
time at which a film, print or digital file stored is no longer suited for its intended purpose
3.67
endpoint
defined measurable change in an image characteristic (such as density), often indicating the end of an ageing
test
3.68
envelope
bag
enclosure that is sealed with adhesive, mechanically joined or heat-sealed on two edges with a bottom fold
and one side open
3.69
extended-term storage conditions
storage conditions suitable for the preservation of recorded information having permanent value
3.70
ferrotyping
changes in surface gloss resulting from intimate contact with another surface, often associated with high
humidity
NOTE The term ferrotyping is derived from a historical term associated with silver halide photography. It is a
process used to produce a very high gloss surface on a silver halide print in which a damp print is placed in contact with a
highly polished surface, such as chromium-plated steel, and dried under conditions of elevated temperature and pressure.
3.71
film base
plastic support for the emulsion, receiving or backing layers
3.72
fire-protective storage
facility designed to protect records against excessive temperatures, water and other fire-fighting agents and
steam developed by insulation of safes or caused by the extinguishing of fires and collapsing structures
3.73
fire-resistant vault
fire-resistant vault as defined in appropriate national standards and regulations
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ISO 18913:2012(E)
3.74
flange
fixed or removable circular disc that is connected to the hub to make a reel for the purpose of protecting the
roll of recording materials
cf. reel (3.160)
3.75
folder
single sheet that is folded, does not have adhesive seams and can be made from either paper or plastic
3.76
folding endurance
measure of fatigue resistance after multiple flexing
3.77
frost point
temperature to which moisture-laden air must be cooled for frost or ice formation
3.78
full-reversal processing
reversal photographic processing that consists of development, bleach, clear, reexposing and second
development, followed by fixing and washing
3.79
gelatine plate, gelatine dry plate
glass sheet bearing a silver halide/gelatine layer which yields a visible image after exposure and processing
3.80
glass transition
reversible change in an amorphous polymer from or to a viscous or rubber condition from or to a hard and
relatively brittle one
3.81
glass transition temperature
T
g
approximate mid-point of the temperature range over which glass transition takes place
NOTE 1 T can be determined readily only by observing the temperature at which a significant change takes place in a
g
specific electrical, mechanical or other physical property.
NOTE 2 T can also be sensitive to the moisture content of the polymer.
g
3.82
graininess
high frequency density variation
[2]
NOTE ISO 13660:2001 contains the following numeric definition: “Aperiodic fluctuations in density at a spatial
frequency greater than 0,4 cycles per millimetre in all directions”.
3.83
heads out
configuration of roll film or magnetic tape stored on its core or reel or in its cassette, such that the film or tape
is positioned to play from the beginning of the recorded information
3.84
hub
metal or plastic cylinder on which recording material is wound
cf. core (3.42)
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ISO 18913:2012(E)
3.85
humidistat
device that senses the moisture content of the air for the purpose of controlling it
3.86
humidity coefficient of expansion
change in dimension per unit length per a 1 % change in the relative humidity at constant temperature
3.87
humidity expansion/contraction
dimensional change caused by the gain/loss of moisture as a result of changes in the relative humidity of the
ambient air at constant temperature
3.88
humidity fastness
ability of a reflection print to resist changes in density or sharpness upon extended exposure to high or low
relative humidity
3.89
hygrometer
instrument that measures the moisture content of a sample of air
3.90
information
data recorded and/or stored in a system
3.91
ink jet print
digital print made by the deposition of ink droplets
3.92
insulated record container
storage box designed to withstand elevated temperatures and conforming to national standards and
regulations
3.93
insulated record containers (Class 150)
insulated record containers (Class 150) as defined in appropriate national standards and regulations
3.94
isoperm lines
lines of constant life plotted as a function of temperature and relative humidity
3.95
jacket
two transparent sheets separated by divider strips with single or multiple film channels (sleeves) made to hold
single or multiple film images
3.96
just noticeable difference
the smallest detectable difference between a starting and secondary level of a particular sensory stimulus,
usually preceded by a percent (commonly 50 %) indicating the percentage of trials for which that difference is
noticed
3.97
lacquer
coating composition that is based on synthetic thermoplastic film-forming material dissolved in organic or
aqueous solvent that dries primarily by solvent evaporation
NOTE Lacquers may include matting agents, plasticizers, cellulose derivative, acrylic polymer and solvents.
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ISO 18913:2012(E)
3.98
laminate
layer of material that goes over the top or bottom of a specimen
NOTE Usually water resistant to provide physical and/or ultraviolet (UV) light protection of the specimen during a
weathering test.
3.99
laminate – film
clear polyester or vinyl layer applied using thermosetting, pressure-sensitive or contact adhesive to one or
both surfaces of a print to improve durability
3.100
laminate – liquid
water-based, solvent-based or UV-curable liquid protective coating designed for use with prints, generally
applied with roller machine or sprayed
3.101
lantern-slide plate
glass sheet bearing a silver halide/gelatine layer which yields a visible image after exposure and processing
NOTE 1 The image layer of a lantern-slide plate is usually protected with a cover glass, bound on all edges with
adhesive tape, as this type of plate is viewed by projection.
NOTE 2 Albumen and colour-screen plates are also found as lantern slides.
3.102
leader
flexible plastic or paper strip which can be spliced to either end of a roll of recording material
3.103
leafing
multiple popped strand(s) in a magnetic-tape wind
cf. stepped pack (3.186)
3.104
length direction
direction of the film or paper parallel to its forward movement in the film or paper-making machine
NOTE This is also termed “grain” or “machine direction” in the case of papers.
3.105
life expectancy
LE
rating for the life expectancy of recording materials and associated retrieval systems
NOTE The number following the LE symbol is a prediction of the minimum life expectancy in years for which
information can be retrieved without significant loss when stored at the conditions as defined in the relevant standards.
EXAMPLE LE-100 indicates that information can be retrieved after at least 100 years' storage.
3.106
lightfastness
ability of a reflection print or transparency to resist fading or staining upon extended exposure to light
3.107
lignin-free
paper or paperboard with a Kappa number of 7,0 or less, corresponding to a lignin concentration of
approximately 1,0 % or less by mass
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ISO 18913:2012(E)
3.108
long-term preservation
the process of retaining information so that it remains useful for multiple generations, i.e. more than 100 years
3.109
loose pack
undesirable pack condition in a roll of recording material, such that the outer portion of the roll can be moved
and tightened by pulling on the end
3.110
macroenvironment
atmospheric conditions (temperature, relative humidity and pollutants) in a large area in which records are
kept
3.111
magnetic field intensity
magnitude of the magnetic field, in amperes per metre, at a point in space
3.112
mar resistance
the ability of a coating to resist permanent deformation or fracture, resulting from the application of dynamic
mechanical force
NOTE It is directly related to the coating’s ability to retain gloss in abraded areas.
3.113
matting agent
liquid that is applied to modify the optical characteristics of an assembly by reducing the gloss of a surface
and that also alters the physical characteristics of this surface by increasing the surface roughness, reducing
the susceptibility of the surface to stick to other surfaces
3.114
medium (media, pl)
material on which information is recorded
cf. carrier (3.25)
3.115
medium-term storage conditions
storage conditions suitable for the preservation of recorded information for a minimum of 10 years
3.116
microenvironment
atmospheric conditions (temperature, relative humidity and pollutants) inside a storage enclosure in which
records are kept
3.117
MO disc
optical disc in which the information is recorded using magneto-optical technology in some specified format
and which can be read many times and overwritten many times
3.118
moderately water resistant
print exhibiting some change or damage by water but still considered usable for its intended application
NOTE The damage can manifest itself as slight media curl, partial delamination along an edge, or ring-like
watermarks due to gloss changes or a minor amount of colourant migration. This damage can be mitigated by the rapid
removal of the water (careful blotting, shaking off the water, etc.).
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ISO 18913:2012(E)
3.119
monochrome image
image with recording in one colour or one shade of hue
NOTE In the case of images within the scope of this International Standard, these images are often close to neutral
in colour.
3.120
morphological changes
changes in the physical structure of the association of the molecules
3.121
mottle
non-uniform visual density variation
[2]
NOTE ISO 13660:2001 contains the following numerical definition “Aperiodic fluctuations of density at a spatial
frequency less than 0,4 cycles per millimetre in all directions”.
3.122
natural ageing
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