ISO 18913:2021

INTERNATIONAL ISO
STANDARD 18913
Third edition
2021-12
Imaging materials — Permanence —
Vocabulary
Matériaux pour l'image — Permanence — Vocabulaire
Reference number
© ISO 2021
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
Bibliography .30
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 42, Photography.
This third edition cancels and replaces the second edition (ISO 18913:2012), which has been technically
revised.
iv
Introduction
This document is one of a series dealing with the physical properties and stability of imaging materials.
v
INTERNATIONAL STANDARD ISO 18913:2021(E)
Imaging materials — Permanence — Vocabulary
1 Scope
This document establishes a vocabulary of terms and definitions used in respect of 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, refer to industry standards. However, in
some cases the definition of a term is still evolving and/or is used by different user groups in different
ways. In this case a definition fit for use in Imaging Materials – Permanence work is given and a note to
this effect is included.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
abrasion
loss of material from a surface or deformation of a surface, with changes in gloss, colour, or density, due
to frictional forces as a result of rubbing
Note 1 to entry: Surface deformations can result in changes in gloss and colour.
Note 2 to entry: See also mar resistance (3.122), rub resistance (3.186), scuff (3.190), smudge (3.201), and wet rub
(3.238).
3.2
absolute humidity
mass of water vapour per unit volume of wet gas
Note 1 to entry: It is a measure of the amount of water present as part of the chemical analysis of the space, i.e.,
how much water is available for chemical activity.
Note 2 to entry: See also dew point (3.56) and relative humidity (3.181).
3.3
accelerated ageing
procedure to simulate normal ageing process by subjecting a product to stresses (3.216) that are more
severe or more frequent than normal environmental or operational stresses, thus shortening the test
period relative to the normal ageing period
3.4
acid-free adhesive
adhesive material that does not release acidic species, such that the cold extraction pH is equal to or
greater than the reference water minus 0,5 and less than 10,0
Note 1 to entry: ISO 18902 provides a cold extraction pH test method, which may be used to establish a
specification for acid-free adhesive materials for intended photographic applications.
Note 2 to entry: An adhesive may contain acids, but the cold extraction pH test only measures acidic species
released into water to determine pH.
3.5
acid-free paper or paperboard
paper or paperboard materials that do not release acidic species, such that the cold extraction pH is
equal to or greater than the reference water minus 0,5 and less than 10,0
Note 1 to entry: ISO 18902 provides a cold extraction pH test method, which may be used to establish a
specification for acid-free or alkaline paper and paperboard materials for intended photographic applications.
Note 2 to entry: A paper or paperboard may contain acids, but the cold extraction pH test only measures acidic
species released into water to determine pH.
3.6
album
binder or book structure having front and back covers in which pages are bound along one edge either
by plastic straps, gluing, sewing, metal posts or rings, and in which photographs are attached and
related contents may be included
3.7
albumen plate
glass sheet bearing a silver halide/albumen layer which yields a visible image after exposure and
processing
3.8
ambient conditions
conditions of the affecting environment
Note 1 to entry: For preservation (3.164) purposes these may or may not be the same as the storage environment
(3.214).
3.9
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 1 to entry: The processed negative (3.134) silver image appears as a positive when backed by a dark field.
3.10
analogue print
print where the image is printed from the analogue domain
Note 1 to entry: In graphic printing, the marking information of an analogue print is generated by means of an
off-line produced forme with which the ink is printed on the media. Examples of traditional forme-based ink
printing as defined in ISO 12637-1 are flexographic, letterpress, letterset, (offset) lithographic, gravure, intaglio,
pad-transfer printing, screen, and stencil printing.
Note 2 to entry: Ambiguous use also for chromogenic (silver-halide) print, where image information is exposed
conventionally (“analogue”) through a film negative (3.134) or positive, or actual scene images are exposed
through camera lenses.
Note 3 to entry: See also digital print (3.58).
3.11
anti-blocking agent
additive or component which prevents sticking (3.211) or fusing of adjacent surfaces
EXAMPLE Talc, silicates or matte beads.
Note 1 to entry: See ISO 18902.
Note 2 to entry: See blocking (3.20)
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 (3.80) of a cassette that is used to facilitate threading of magnetic tape on the hub
(3.46) and inspection of the wind (3.240)
3.14
archival
medium (3.124) that can be expected to preserve images at a stated level of quality or usefulness for a
specified extended period of years
3.15
Arrhenius plot
plot of the logarithm of the time for a given change in a characteristic proportional to the reaction rate
versus the reciprocal of the temperature expressed in K (Kelvin)
Note 1 to entry: The Arrhenius plot can be used to predict behaviour at a temperature lower than that at which a
test is run, as described in ISO 18924.
Note 2 to entry: Changes in characteristics may include dye loss, tensile strength change, D (3.55) yellowing,
min
etc.
3.16
artificial accelerated weathering
artificial weathering
laboratory weathering
exposure of a material in a laboratory weathering device to conditions which may be cyclic and may be
intensified compared with conditions encountered in outdoor or in-service exposure
Note 1 to entry: The purpose of artificial accelerated weathering is to accelerate changes in the material that can
correspond to changes observed after long-term, continuous, natural or end-use exposure.
3.17
base
support in a recording material (3.176) on which the image receiving/recording layers or magnetic layer
(and, if necessary, the back layer) are coated
Note 1 to entry: Substrate (3.218) is the preferred term for the physical support of a receiving layer. The term
'base' should be used only in reference to pH.
3.18
blister
localized delamination (3.54) 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 (3.142) measured at the input of the first (C1)
decoder (before any error correction is applied)
Note 1 to entry: 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
undesired adherence between sheets of printed material
Note 1 to entry: Blocking can occur under a variety of pressures, temperatures, and humidity conditions, while
in storage or in use.
Note 2 to entry: Blocking effects include delamination (3.54), paper splitting, tearing, gloss changes, physical
image transfer, permanent bonding to adjacent materials and prints, and edge deformation.
Note 3 to entry: See also 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
(3.32)
Note 1 to entry: Be aware that “blue print” is not to be confused with “blueprint”.
Note 2 to entry: A common cause in the case of a blue print is when a print has been lacquered in a very humid
environment or was not thoroughly dried before lacquering.
3.22
book printing
printing of books and publishing of monographs (reference books, photo-books, comic, paperback,
textbooks and directories)
Note 1 to entry: See also commercial printing (3.38), newspaper and periodical printing (3.135), package printing
(3.146), sign printing (3.195), and transactional and direct mail printing (3.228).
3.23
brittleness
property of a material that causes it to crack or break when deformed by bending or flexing
3.24
buffered
characteristic of paper or paperboard materials containing a certain amount of alkali reserve
to neutralize future attacks by acidic species, either from atmospheric pollutants or released from
material degradations in the ageing process
Note 1 to entry: See ISO 10716 for a standard test method to determine the amount of alkaline reserve in paper
materials.
Note 2 to entry: See ISO 18902 for specifications for alkaline reserve in paper and paper boards for albums,
framing, and storage materials.
3.25
can
metal or plastic container (3.44) for a roll of recording material (3.176), such as
photographic film or magnetic tape
3.26
carrier
medium (3.124) upon which information is recorded
3.27
cartridge
housing for a roll of recording media, such as photographic film or magnetic tape,
wound on a single hub (3.46) or reel (3.178)
Note 1 to entry: The term “cartridge” is also used in some cases to describe a colorant (e.g., ink, toner) container.
Note 2 to entry: See also cassette (3.28).
3.28
cassette
housing for a roll of recording material (3.176), such as photographic film or
magnetic tape, whose ends are attached to two hubs or reels
Note 1 to entry: See also cartridge (3.27).
3.29
cellulose-acetate base
base for recording materials (3.176) composed mainly of cellulose esters of acetic acid
3.30
cellulose-ester base
base for recording materials (3.176) composed mainly of cellulose esters of acetic, propionic, or butyric
acid, or mixtures thereof
3.31
cellulose-nitrate base
base for recording materials (3.176) composed mainly of cellulose esters of nitric acid with a plasticizer
(3.157) such as camphor
3.32
chromogenic print
gelatin print in which the colour image is composed of cyan, magenta, and yellow dye layers formed by
a coupling reaction between the dye couplers (dye precursors) in the emulsion layers (3.69) as a result
of silver development
Note 1 to entry: During development of exposed silver halide, the resulting oxidized colour developer molecules
will react with the dye couplers (dye precursors, typically incorporated in the emulsion layers during
manufacture but could be added during development), forming microdroplets of cyan, magenta, and yellow dyes.
The silver image is then bleached and dissolved via a bleach-fix bath and then is washed away, and the colour
image remains.
Note 2 to entry: To further distinguish chromogenic prints, note that in chromolytic prints, which use the
silver dye bleach process typical for positive printing (as in Cibachrome and Ilfochrome), the dyes are already
incorporated during the production process and present before exposure. During development the latent silver
image is processed to develop silver. Next the silver dye bleach reaction destroys the dye into colourless products
and dissolves the silver. Finally, the layer sequence in chromolytic prints is different from that of chromogenic
prints, the chromolytic dye layers top to bottom are yellow, magenta, cyan.
Note 3 to entry: See also blue print (3.21), cyan spots (3.50), red print (3.177), and yellow print (3.244).
3.33
class 100 000 clean room
controlled environment in which the level of airborne contaminates meets standard requirements
Note 1 to entry: See ISO 14644-1 for the requirements to meet.
3.34
cockle
deformation of a sheet of paper due to unequal shrinkage giving it a planar distortion in the form of
waves or ripples
Note 1 to entry: See also edge fluting (3.67) and waviness (3.236).
3.35
collodion plate
collodion wet or dry plate
glass sheet bearing a thin silver halide/cellulose nitrate layer which yields a visible image after exposure
and processing
3.36
colorant
dye or pigment
Note 1 to entry: Colorant is typically a component of transfer ribbon, chromogenic material, toner or ink.
3.37
colour screen plate
glass sheet bearing a colour screen consisting of dyed elements in contact with a silver halide/gelatin
layer which yields a visible image after exposure and processing
3.38
commercial printing
printing for graphic products for commercial application such as catalogue, advertisement (flyer,
pamphlet, leaflet, direct marketing, free magazines), and others (manuals)
Note 1 to entry: See also book printing (3.22), newspaper and periodical printing (3.135), package printing (3.146),
sign printing (3.195), and transactional and direct mail printing (3.228).
3.39
compact disc
CD
CD-ROM (3.40) optical disc (3.142) format in which the information layer is located at one surface of a
substrate (3.218) and the data can be read by an optical beam
Note 1 to entry: Described in IEC 60908.
Note 2 to entry: See also rewritable compact disc (3.185), compact disc-recordable (3.41), and read-only-medium
compact disc (3.173).
3.40
compact disc read-only memory
CD-ROM
optical disc (3.142) to which information is transferred during manufacture to certain areas in the
compact disc format
Note 1 to entry: The information can be read many times.
Note 2 to entry: See also rewritable compact disc (3.185), compact disc (3.39), compact disc-recordable (3.41), and
read-only-medium compact disc (3.173).
3.41
compact disc-recordable
CD-R
recordable optical disc (3.142) in which information can be recorded to certain areas in compact disc
format
Note 1 to entry: Information can be recorded one time and read many times.
Note 2 to entry: The term "compact disc-write once" (CD-WO) has also been used to describe this type of disc.
Note 3 to entry: See also compact disc read-only memory (3.40), rewritable compact disc (3.185), compact disc
(3.39), and read-only-medium compact disc (3.173).
3.42
conditioning
exposure of a specimen to air at a given relative humidity (3.181) and temperature until equilibrium is
reached
3.43
conservation
all activities taken toward the long-term preservation (3.164) of cultural heritage, including examination,
documentation, treatment, and preventive care, supported by research and education
3.44
container
box, can (3.25), or carton used for storage and shipping of recording materials
(3.176)
EXAMPLE The box into which a reel (3.178), cassette (3.28), cartridge (3.27), optical disc (3.142) or shell
(3.192) is placed.
Note 1 to entry: Reels (3.178), cassettes (3.28), cartridges (3.27), and shells (3.192) are not containers.
3.45
copy
reproduction of the information from a master
Note 1 to entry: A copy is a reproduction that may be on a different media and in a different size or format than
the master, whereas a duplicate (3.64) is an identical reproduction.
3.46
core
hub
metal or plastic cylinder on which recording material (3.176) is wound
Note 1 to entry: See also flange (3.80), reel (3.178), slot (3.200), and tape pack (3.220).
3.47
crazing
network of fine cracks on the surface of a print or film that is the result of environmental stresses on
the surface layer
3.48
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
3.49
curl
departure of film, paper or magnetic tape from physical flatness with the tendency to curve into a
cylindrical shape
Note 1 to entry: See ISO 11556.
3.50
cyan spots
defect that results when the ultraviolet absorber in an older technology chromogenic print (3.32)
crystallises and permits the back-scattering of light
3.51
dark stability
ability of a print, negative (3.134), or transparency (3.230) to resist fading or staining due to ambient
environmental factors in the absence of light
3.52
daylight filter
optical filter (or set of filters) used to modify the spectral irradiance (3.203) of a light source to simulate
outdoor terrestrial daylight
3.53
daylight through window glass filter
window glass filter
optical filter (or set of filters) used to modify the spectral irradiance (3.203) of a light source to simulate
outdoor terrestrial daylight transmitted through standard architectural window glass
3.54
delamination
separation of a laminated assembly into its constituent layers, either in whole or in part
3.55
density minimum
minimum density
D
min
density corresponding to the maximum transmittance, in the case of film, or reflectance, in the case of
paper, that a photographic product can achieve
3.56
dew point
temperature at which moisture begins to condense on a surface, corresponding to saturation for a given
absolute humidity (3.2)
EXAMPLE The higher the absolute humidity of air, the higher the dew-point temperature of the air. See also,
relative humidity (3.181).
3.57
differential dimensional change
difference between the dimensional change (3.60) or dimensional change after ageing (3.61) of a material
in the two principal directions of length and width
Note 1 to entry: 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.
3.58
digital print
print where the image is printed directly from the digital domain
Note 1 to entry: Digital print is a print made directly from digital data in a process such that the image forming
mechanisms are refreshed for each impression, thus each impression can have different content.
Note 2 to entry: Offset printing in its various forms as defined in the ISO 12647 (all parts) is typically categorized
as “analogue printing” even though data may stem from the digital domain as in the case of computer-to-plate
systems. See analogue print (3.10)
Note 3 to entry: 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.
3.59
digital versatile disc
DVD
optical disc (3.142) format in which one or more information layers are located between two substrates
(3.218) and the data can be read by an optical beam
Note 1 to entry: Formerly called digital video disc.
3.60
dimensional change
permanent change in dimension caused by photographic processing alone
Note 1 to entry: This can be the conventional wet chemical processing, vapour processing, or heat processing. The
dimensional change is measured after conditioning (3.42) at the same relative humidity (3.181) and temperature
as used for the original measurement and is expressed as a percentage.
Note 2 to entry: See also differential dimensional change (3.57), dimensional change after ageing (3.61), and
dimensional hysteresis (3.62).
3.61
dimensional change after ageing
dimensional change due to processing plus ageing
permanent dimensional change (3.60) that occurs as a result of processing plus ageing of the processed
material
Note 1 to entry: It is measured after conditioning (3.42) of the processed, aged film or paper at the same relative
humidity (3.181) and temperature as used for the original measurement and is expressed as a percentage.
3.62
dimensional hysteresis
difference in the absolute dimensions of a specimen in equilibrium with air at a given relative humidity
(3.181), when conditioned from a higher relative humidity and when conditioned from a lower relative
humidity
Note 1 to entry: See also differential dimensional change (3.57) and dimensional change (3.60).
3.63
direct spectral irradiance
irradiation from a source without shading, scattering, or additional filtering at a specific wavelength
over a narrow bandwidth, or as a function of wavelength; also, the derivative with respect to wavelength
-2 -1
of irradiance, represented as Eλ or E(λ)[W·m ·nm ]
Note 1 to entry: In the context of solar irradiance, an alternative use of the term pertains to the radiation that is
not scattered by the atmosphere (water vapor and other constituents). Its counterpart is “diffuse” radiation. The
total of direct and diffuse equals what is called “global” radiation.
Note 2 to entry: See also spectral irradiance (3.203).
3.64
duplicate
identical (1:1) reproduction of a master, comprised of the same media and size
Note 1 to entry: A duplicate is an identical reproduction whereas a “copy”, as defined in this document, is a
reproduction that may be on a different media and in a different size or format than the master.
3.65
durability
resistance of an image print to physical, mechanical, and environmental stresses
3.66
dye diffusion thermal transfer (D2T2) print
digital print (3.58) made using thermal print heads controlled by digital data and using donor ribbons
coated with dye-based colorants that diffuse due to heating to reproduce images on an image receiving
layer of a substrate (3.218)
Note 1 to entry: 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.
Note 2 to entry: See ISO 12637-1.
3.67
edge fluting
wave-shaped deformation along the edges of cut sheets, which may be caused by an expansion of the
edge of the material, particularly when the edge is exposed to greater variations in temperature and
humidity than the centre of the sheet
Note 1 to entry: See also cockle (3.34) and waviness (3.236).
3.68
electrophotographic print
print made from electrostatically charged toner particles or droplets that are transferred from a
photoconductive medium (3.124)
3.69
emulsion layer(s)
image or image-forming layer(s) of silver halide photographic films (3.152), papers, and plates
3.70
encapsulation
process of placing a document between two sheets of plastic (usually polyester), which are sealed at the
edges, in order to provide support and protect it from handling and the atmosphere
Note 1 to entry: Usually done using protective sheets that are larger in dimension than the specimen and then
sealing at the overlaps.
Note 2 to entry: See also irreversible encapsulation (3.102) and reversible encapsulation (3.184).
3.71
enclosure
box, case, cartridge, folder, envelope, sleeve, or clam shell that is intended for physical protection against
mechanical damage
Note 1 to entry: See also envelope or bag (3.74), open enclosure (3.140), photographic enclosure (3.151), pocket-style
page (3.158), protective enclosure (3.168), seam (3.191), sleeve or sheath (3.197), and storage enclosure (3.213).
3.72
end-of-life
time at which a film, print or digital file stored is no longer suited for its intended purpose
3.73
endpoint
defined measurable densitometric, colorimetric, or physical change in a print parameter used to define
the point at which a print is no longer usable or acceptable in a particular application
Note 1 to entry: The term “endpoint” is not to be confused with “end of test”, which is the point at which a
test is terminated after a pre-defined level of physical or chemical stress (3.216) has been applied, or after an
accumulated exposure of the stresses which is determined based on the assumption of the exposure level of the
use or the required level of longevity for the product.
3.74
envelope or bag
enclosure (3.71) that is sealed with adhesive, mechanically joined or heat-sealed on two-edges with a
bottom fold and one side open
3.75
extended-term storage conditions
storage conditions suitable for the preservation (3.164) of recorded information having permanent
value
3.76
ferrotyping
changes in surface gloss resulting from intimate contact with another surface, often associated with
high humidity
Note 1 to entry: 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 (3.196) 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.
3.77
film substrate
film base
transparent support in a film recording material (3.176) on which the image recording layers are coated
Note 1 to entry: See substrate (3.218).
3.78
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
3.79
fire-resistant vault
fire-resistant vault as defined in appropriate national standards and regulations
3.80
flange
fixed or removable circular disc that is connected to the hub (3.46) to make a reel (3.178) for the purpose
of protecting the roll of recording materials (3.176)
3.81
folder
single sheet that is folded, does not have adhesive seams, and can be made from either paper or plastic
3.82
folding endurance
measure of the ability of a material to withstand folding under specified conditions of test
Note 1 to entry: See ISO 5127.
3.83
frost point
temperature to which moisture-laden air must be cooled for frost or ice formation
3.84
full-reversal processing
reversal photographic processing that consists of development, bleach, clear, re-exposing and second
development, followed by fixing and washing
3.85
gelatin plate, gelatin dry plate
glass sheet bearing a silver halide/gelatin layer which yields a visible image after exposure and
processing
3.86
general indoor light filter
optical filter (or set of filters) use to modify the spectral irradiance (3.203) of a light source to simulate
a typical spectral irradiance observed in a shaded part of a room in distance from windows, which is
indirectly illuminated by daylight through window glass filter (3.53)
Note 1 to entry: See ISO 18937.
3.87
glass transition
reversible change in an amorphous polymer from, or to, a viscous or rubber condition to, or from, a
hard and relatively brittle one
Note 1 to entry: See also glass transition temperature (3.88).
3.88
glass transition temperature
T
g
mid-point of the temperature range over which glass transition (3.87) takes place
Note 1 to entry: T can be determined readily only by observing the temperature at which a significant change
g
takes place in a specific electrical, mechanical or other physical property.
Note 2 to entry: T can also be sensitive to the moisture content of the polymer.
g
3.89
graininess
appearance of unintended, microscopic, but visible, aperiodic fluctuations of lightness and colour, with
higher frequency compared to mottle (3.131)
Note 1 to entry: ISO/IEC 24790 contains the following note applicable to measurement: “Microscopic means:
variations with spatial frequencies greater than about 0,4 cy/mm.”
3.90
heads out
configuration of roll film or magnetic tape stored on its core (3.46), reel (3.178), or in its cassette (3.28),
such that the film or tape is positioned to play from the beginning of the recorded information
3.91
humidistat
device that senses the moisture content of the air for the purpose of controlling it
3.92
humidity coefficient of expansion
change in dimension per unit length per a 1 % change in the relative humidity (3.181) at constant
temperature
3.93
humidity expansion/contraction
dimensional change (3.60) caused by the gain/loss of moisture as a result of changes in the relative
humidity (3.181) of the ambient air at constant temperature
3.94
humidity fastness
ability of a reflection print (3.179) to resist changes in density or sharpness upon extended exposure to
high or low relative humidity (3.181)
3.95
hygrometer
instrument that measures the moisture content of a sample of air
3.96
image permanence
ability of a printed image to remain stable over long periods of time
3.97
indirect spectral irradiance
irradiation from a source shaded, scattered, or through additional filtering (e.g. window glass) at a
specific wavelength over a narrow bandwidth, or as a function of wavelength; also, the derivative with
-2 -1
respect to wavelength of irradiance, represented as Eλ or E(λ)[W·m ·nm ]
EXAMPLE Indirect daylight – such as “daylight through window glass filter” and “daylight through general
indoor filter” – is an important case.
Note 1 to entry: See also spectral irradiance (3.203).
3.98
ink jet print
digital print (3.58) made by the deposition of ink droplets
3.99
insulated record container
storage box designed to provide an environmental buffer against temperature and humidity fluctuations
3.100
insulated record containers (Class 150)
insulated record containers (Class 150) as defined in appropriate national standards and regulations
3.101
interval scale
scale established by a psychophysical method, which, in addition to possessing the
attributes of rank order (3.170), is distinguished by the fact that equal differences between numerical
values correspond to equal differences between properties measured, or in sensory analysis, intensities
perceived
Note 1 to entry: Larger values correspond to larger perceived intensities and the size of the difference between
two values reflects the size of the difference in perceived intensity of the property being measured. However, a
numerical value of zero may not indicate a total absence of the property and the ratio of two values cannot be
assumed to reflect the ratio of the perceived intensities.
3.102
irreversible encapsulation
encapsulation (3.70) that cannot be removed without damaging the object
Note 1 to entry: Use of liquid coatings (liquid laminates) on two sides is not considered a form of encapsulation.
3.103
irreversible mounting
mounting (3.132) that employs pressure sensitive, thermoplastic or solvent-based adhesives that are
not easily reversed without damage to the print, or may not be photo-safe (3.156)
3.104
isoperm lines
lines of constant life plotted as a function of temperature and relative humidity (3.181)
3.105
jacket
two transparent sheets separated by divider strips with single or multiple film channels (sleeves), also
known as pocket pages or page protectors, made to hold single or multiple film images
3.106
just noticeable difference
stimulus difference that leads to a 75:25 proportion of responses in a paired comparison task
Note 1 to entry: See ISO 20462-1.
3.107
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 1 to entry: Lacquers may include matting agents (3.123), plasticizers (3.157), cellulose derivative, acrylic
polymer, and solvents. Lacquer, polyurethane, and shellac are all types of varnish (3.232).
3.108
laminate
layer of material that goes over the top or bottom of a specimen
Note 1 to entry: Usually water resistant to provide physical and/or ultraviolet (UV) light protection of the
specimen.
3.109
laminate
clear polyester or vinyl layer applied using thermosetting, pressure-sensitive or contact adhesive
to one or both surfaces of a print to improve durability (3.65)
3.110
laminate
water-based, solvent-based, or UV-curable liquid protective coating designed for use with
prints, generally applied with a roller machine or spray system
3.111
laminated assembly
multilayer structure typically comprising a paper support, one or more barrier layers, an imaging layer,
and a protective laminate top layer
3.112
lantern-slide plate
glass sheet bearing a silver halide/gelatin, silver halide/albumen, silver halide/collodion, or colour
screen image that is usually protected with a cover glass bound on all sides with an adhesive tape and is
intended for viewing by projection
Note 1 to entry: A lantern slide is generally a positive image. There are also later lantern slides for projection
which were made by sandwiching a sheet of film (black and white or colour film) between two plates of glass and
bound on all edges with adhesive tape.
3.113
leader
flexible plastic or paper strip which can be spliced to either end of a roll of recording material (3.176)
3.114
leafing
multiple popped strand(s) (3.162) in a magnetic-tape wind
Note 1 to entry: See also stepped pack (3.210).
3.115
length direction
machine direction
direction of the film or paper parallel to its forward movement in the film or paper-making machine
Note 1 to entry: This is also termed “grain” in the case of papers.
Note 2 to entry: See also width direction (3.239).
3.116
life expectancy
LE
rating for the life expectancy of recording materials (3.176) and associated retrieval systems
Note 1 to entry: 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.
3.117
lightfastness
ability of a reflection print (3.179) or transparency (3.230) to resist fading, staining, or physical
degradation, upon extended exposure to light
3.118
lignin-free
characteristic of 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
3.119
loose pack
undesirable pack condition in a roll of recording material (3.176), such that the outer portion of the roll
can be moved and tightened by pulling on the end
3.120
macroenvironment
atmospheric conditions, being temperature, relative humidity (3.181), and pollutants, in a large area in
which records are kept
3.121
magnetic field intensity
magnitude of the magnetic field, in amperes per metre, at a point in space
3.122
mar resistance
ability of a coating to resist permanent deformation or fracture without removal of material, under the
action of dynamic mechanical force; as such is directly related to the coating’s ability to retain gloss in
response to such force
Note 1 to entry: In general, the distinction between abrasion resistance and mar resistance is that abrasion
implies removal of material from the surface, while mar implies smear or deformation of the surface without
mass loss.
Note 2 to entry: See also abrasion (3.1) and rub resistance (3.186).
3.123
matting agent
substance applied to modify the optical characteristics of an assembly by reducing the gloss of a surface
Note 1 to entry: A matting agent may also alter the physical characteristics of a surface by increasing the surface
roughness, reducing susceptibility of the surface to stick to other surfaces
3.124
medium (media, pl)
material on which information is recorded
Note 1 to entry: See also carrier (3.26).
3.125
medium-term storage conditions
storage conditions suitable for the preservation (3.164) of recorded information for a minimum of 10
years
3.126
microenvironment
atmospheric conditions, being temperature, relative humidity (3.181), and pollutants, inside a storage
enclosure (3.213) in which records are kept
3.127
MO disc
optical disc (3.142) 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
3.128
moderately water resistant
print that exhibits some change or damage by water but is still considered usable for its intended
application
Note 1 to entry: The damage can manifest itself as slight media curl (3.49), partial delamination (3.54) along an
edge, ring-like watermarks due to gloss changes or a minor amount of colorant migration. This damage can be
mitigated by the rapid removal of the water (careful blotting, shaking off the water, etc.).
3.129
monochrome image
image with recording in one colour or one shade of hue; in the case of images within the scope of this
standard these images are often close to neutral in colour
3.130
morphological changes
changes in the physical structure of the association of the molecules
3.131
mottle
measure of the appearance of unintended, aperiodic macroscopic fluctuations of lightness and colour,
with lower frequency compared to graininess (3.89), but higher frequency compared to shading
Note 1 to entry: ISO/IEC 24790 contains the following note applicable to measurement “Macroscopic means:
variations with spatial frequencies less than about 0,4 cy/mm.”
3.132
mounting
local attachment or overall adhesion of a photographic image/print to a rigid material (paperboard,
metal and/or plastic) for purposes of framing, display, or physical support
EXAMPLE A local attachment can be at a corner using a mounting corner, hinge or adhesive.
Note 1 to entry: See also reversible conservation mounting (3.183) and irreversible mounting (3.103).
3.133
natural ageing
changes in the characteristics of imaging materials that occur under typical use or storage conditions
Note 1 to entry: See also ambient conditions (3.8).
3.134
negative
photographic image in which the light and dark regions and colours are reversed, which upon projection
with transmitted light onto another negative silver halide sensitised print medium (3.124) will produce
a positive image after processing
3.135
newspaper and periodical printing
printing for graphic products for newspaper (colour, B&W) and periodical magazines (monthly, weekly)
Note 1 to entry: See also book printing (3.22), commercial printing (3.38), package printing (3.146), sign printing
(3.195), and transactional and direct mail printing (3.228).
3.136
Newton's rings
faint coloured rings or fringe patt
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