SIST ISO 5-1:2010

SLOVENSKI STANDARD
SIST ISO 5-1:2010
01-maj-2010
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SIST ISO 5-1:1996
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Photography and graphic technology - Density measurements - Part 1: Geometry and
functional notation
Photographie et technologie graphique - Mesurages de la densité - Partie 1: Géométrie
et notation fonctionnelle
Ta slovenski standard je istoveten z: ISO 5-1:2009
ICS:
01.040.37 Slikovna tehnologija (Slovarji) Image technology
(Vocabularies)
37.040.01 Fotografija na splošno Photography in general
SIST ISO 5-1:2010 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 5-1:2010

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SIST ISO 5-1:2010

INTERNATIONAL ISO
STANDARD 5-1
Second edition
2009-12-01

Photography and graphic technology —
Density measurements —
Part 1:
Geometry and functional notation
Photographie et technologie graphique — Mesurages de la densité —
Partie 1: Géométrie et notation fonctionnelle




Reference number
ISO 5-1:2009(E)
©
ISO 2009

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SIST ISO 5-1:2010
ISO 5-1:2009(E)
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© ISO 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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ii © ISO 2009 – All rights reserved

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SIST ISO 5-1:2010
ISO 5-1:2009(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Equations .4
5 Instrument representation.5
6 Coordinate system .6
7 Description of geometry .7
8 Functional notation .8
8.1 General .8
8.2 Geometric conditions.8
8.3 Spectral conditions .11
8.4 Examples of functional notation.12
Annex A (informative) Terms and definitions used in other parts of ISO 5 .13
Bibliography.16

© ISO 2009 – All rights reserved iii

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SIST ISO 5-1:2010
ISO 5-1:2009(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 5-1 was prepared by ISO/TC 42, Photography, and ISO/TC 130, Graphic technology, in a Joint Working
Group.
This second edition cancels and replaces the first edition (ISO 5-1:1984), which has been technically revised.
In the course of this technical revision, all parts of ISO 5 have been reviewed together, and the terminology,
nomenclature and technical requirements have been made consistent across all parts.
ISO 5 consists of the following parts, under the general title Photography and graphic technology — Density
measurements:
⎯ Part 1: Geometry and functional notation
⎯ Part 2: Geometric conditions for transmittance density
⎯ Part 3: Spectral conditions
⎯ Part 4: Geometric conditions for reflection density
iv © ISO 2009 – All rights reserved

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SIST ISO 5-1:2010
ISO 5-1:2009(E)
Introduction
The measurement of the transmission and reflection characteristics of objects is essential to the science of
photography and graphic arts. When light, or other radiant energy, is incident upon an object, it is either
absorbed or propagated. Propagation can involve reflection, transmission, refraction, diffraction, scattering,
fluorescence, and polarization. The propagated light is distributed in various directions about the object. In
most practical applications it is neither necessary nor desirable to consider the light distributed in every
direction, but only that which leaves the object in the direction for which there is response by a receiver, such
as the eye.
The object modulates the flow of radiant energy from the illuminator to the receiver. The time rate of flow of
radiant energy is called radiant flux, or simply flux. This part of ISO 5 provides methods to describe the
measurements of the flux modulation in any system. To specify such a system accurately, geometric
characteristics of the system, the spectral distribution of the flux incident on the object to be measured, and
the spectral responsivity of the receiver need to be given. If the reflection characteristics of the illuminator or
receiver affect the measurement, as they do in transmission measurements by the opal glass method, they
need to be specified.
The area under consideration is defined by a sampling aperture, the dimensions of which can be important in
some applications and need to be specified if the object has appreciable non-uniformity. If the measurement is
to quantify the way the object would modulate flux in a given practical application, such as viewing or contact
printing, the geometric and spectral conditions of measurement need to simulate those conditions in the
practical application.
Modulation is measured and expressed as a dimensionless ratio of fluxes; that is, the flux propagated in the
direction of the receiver and that part of the spectrum of interest divided by some reference flux. The reference
flux can be the incident flux or the flux propagated through the system when the object is replaced by an ideal
object. For some purposes, a logarithmically scaled measure of modulation is more useful than the measured
arithmetic ratio. In such cases, it is customary to use optical density defined as the negative logarithm to base
10 of the ratio.
Most geometric arrangements used in photographic and graphic arts optical systems can be conveniently and
adequately described in terms of uniform rays of flux bounded by right circular cones. A point on the object is
often illuminated by such a conic distribution, and the geometric form of the pencil of rays reaching the
receiver is generally conic. The pupil of the eye, for example, subtends a conic solid angle at an object point.
In projection systems, the projection lens subtends a conic solid angle at the specimen point. This part of
ISO 5 specifies a conic distribution by the half-angle of the cone and the direction of its axis.
A working knowledge of radiometry is generally required to obtain primary standard measurements of
transmittance and reflectance. In good radiometric practice, for example, the effects of stray light are
minimized by the use of appropriate baffles and proper blackening of certain surfaces. Because the principles
[10]
and practice of radiometry are well known and are fully described in the Handbook of Applied Photometry ,
it is considered unnecessary to provide a detailed specification of radiometric procedures in this part of ISO 5.
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SIST ISO 5-1:2010

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SIST ISO 5-1:2010
INTERNATIONAL STANDARD ISO 5-1:2009(E)

Photography and graphic technology — Density
measurements —
Part 1:
Geometry and functional notation
1 Scope
This part of ISO 5 establishes terms, symbols, functional notations and a coordinate system to describe
geometric and spectral conditions for the measurement of the degree to which a specimen modulates radiant
flux for applications in photography, graphic technology, and radiometry.
This part of ISO 5 primarily provides a system for describing methods of measuring or specifying the
transmission and reflection properties of photographic and graphic arts materials. The geometric and spectral
conditions associated with such measurement are specified in ISO 5-2, ISO 5-3 and ISO 5-4.
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 5-2, Photography and graphic technology — Density measurements — Part 2: Geometric conditions for
transmittance density
ISO 5-3, Photography and graphic technology — Density measurements — Part 3: Spectral conditions
ISO 5-4, Photography and graphic technology — Density measurements — Part 4: Geometric conditions for
reflection density
3 Terms and definitions
1)
For the purposes of this document, the following terms and definitions apply .
3.1
absolute reference reflected flux
Φ
rA
radiant flux that would be reflected by a perfect reflecting diffuser

1) For the convenience of the user, Annex A lists those terms and definitions used in other parts of ISO 5 that are not
used in this part of ISO 5.
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SIST ISO 5-1:2010
ISO 5-1:2009(E)
3.2
absolute reference transmitted flux
Φ
tA
radiant flux that would be transmitted by a perfect transmitting diffuser
3.3
anormal angle
θ
angle between the normal of the reference plane and a direction
NOTE Adapted from ASTM E1767.
3.4
azimuthal angle
η
angle between the x-axis of the reference plane and the projection of a direction onto the reference plane
NOTE Adapted from ASTM E284.
3.5
cone half-angle
κ
angle between the central axis and the edge of the pupil with the apex at the centre of the sampling aperture
3.6
efflux
radiant flux collected by the receiver from the reference plane
NOTE Adapted from ASTM E1767.
3.7
illuminator axis
central axis of the illuminator, usually the optical axis
3.8
illuminator region
intersection of the illuminator beam with the reference plane
3.9
incident flux
Φ
i
radiant flux incident upon the sampling aperture
3.10
influx
radiant flux projected by the illuminator onto the reference plane
NOTE Adapted from ASTM E1767.
3.11
influx spectrum
S
spectral distribution of the radiometric quantity, such as radiance, irradiance or radiant flux, incident upon the
sampling aperture
NOTE This is a function of the source and optics used for the illumination.
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SIST ISO 5-1:2010
ISO 5-1:2009(E)
3.12
ISO 5 standard density
density value obtained using an instrument conforming to one of the geometries specified in ISO 5-2 or
ISO 5-4, and one of the spectral definitions in ISO 5-3
3.13
receiver axis
central axis of the receiver, usually the optical axis
3.14
receiver region
intersection of the receiver beam with the reference plane
3.15
reflectance
ρ
ratio of the reflected flux to the incident flux under specified geometrical and spectral conditions of
measurement
NOTE Adapted from ASTM E284.
3.16
reflectance density
D
ρ
negative logarithm to the base 10 of the reflectance
3.17
reflectance factor
R
ratio of the reflected flux to the absolute reference reflected flux under the same geometrical and spectral
conditions of measurement
3.18
reflected flux
Φ
r
radiant flux that emerges from the specimen surface on which the incident flux falls
3.19
reflection density
D
R
negative logarithm to the base 10 of the reflectance factor
NOTE The International Commission on Illumination (CIE) designates the measurement referred to as “reflection
density” in ISO 5 as “reflectance factor density”. (See IEC 60050-845:1987⏐CIE 17.4:1987.)
3.20
spectral responsivity
s
output signal of a receiver per unit input of radiant flux as a function of wavelength
NOTE Adapted from ASTM E284.
3.21
transmission density
D
T
negative logarithm to the base 10 of the transmittance factor
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SIST ISO 5-1:2010
ISO 5-1:2009(E)
3.22
transmittance
τ
ratio of the transmitted flux to the incident flux under specified geometrical and spectral conditions of
measurement
NOTE 1 In practical instruments for transmittance measurements, the incident flux is defined by the combination of all
of the components that are placed before the reference plane (influx), so the incident flux is provided by the surface of the
opal diffuser for diffuse transmittance and by the film gate for projection density.
NOTE 2 Adapted from ASTM E284.
3.23
transmittance density
D
τ
negative logarithm to the base 10 of the transmittance
NOTE The subscript is the lower case Greek letter tau.
3.24
transmittance factor
T
ratio of the transmitted flux to the absolute reference transmitted flux under the same geometrical and spectral
conditions of measurement
NOTE Adapted from ASTM E284.
3.25
transmitted flux
Φ
t
radiant flux that passes through the specimen and emerges from a surface other than that on which the
incident flux falls
4 Equations
The terms and equations applicable to density measurements are given in Table 1.
Table 1 — Terms and equations for density measurements
Term Equation Term Equation
Φ
t
τ =
Transmittance Transmittance density D =−log τ
τ 10
Φ
i
Φ
r
ρ =
D =−log ρ
Reflectance Reflectance density
ρ 10
Φ
i
Φ
t
T =
D =−log T
Transmittance factor Transmission density
T 10
Φ
tA
Φ
r
R =
Reflectance factor Reflection density D =−log R
R 10
Φ
rA
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SIST ISO 5-1:2010
ISO 5-1:2009(E)
5 Instrument representation
Every instrument used to perform optical density measurements of a specimen typically has three
components:
⎯ an illuminator to project radiant flux onto the specimen,
⎯ a reference plane at which the specimen is placed, and
⎯ a receiver to measure the radiant flux from the specimen.
These components are shown schematically in Figure 1 for a general instrument. The illuminator consists of a
source for providing radiant flux, and a director, which directs the radiant flux from the source onto the
reference plane. Likewise, the receiver consists of a collector, which guides the radiant flux from the reference
plane to the detector, which is a device that converts radiant flux into a measurable signal. Examples of
sources are incandescent and arc lamps, while examples of detectors are photodiodes and photomultiplier
tubes. The central axes, marginal rays, and chief rays of the illuminator and receiver are also shown in
Figure 1 as dashed, thin, and thick lines, respectively.
The illuminator and receiver are optical systems with aperture and field stops. These stops determine the
illuminator and receiver beams, which are the collections of rays that can pass through the systems. The
images of the aperture stops as viewed from the reference plane are the pupils. The illuminator axis is the
central axis of the illuminator beam, and is usually the optical axis of the illuminator, although it could also be
the centroid of the distribution of rays within the beam. The illuminator axis has an angle of illumination with
respect to the normal of the reference plane. Likewise, the receiver axis is the central axis of the receiver
beam and has an angle of observation (or viewing) with respect to the normal of the reference plane. The
intersections of the illuminator and receiver beams with the reference plane are the illuminator and receiver
regions, respectively.

Key
1 director
2 source
3 illuminator
4 receiver
5 detector
6 collector
7 reference plane
Figure 1 — A schematic representation of the three components of an instrument used for
densitometry (illuminator, reference plane, and receiver) and their parts
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SIST ISO 5-1:2010
ISO 5-1:2009(E)
The sampling aperture is the intersection of the illuminator and receiver regions. These two regions are
typically centred at the same location on the reference plane, so the smaller of the two is the sampling
aperture. The sampling aperture is the area of the specimen selected for measurement.
The geometrical and spectral properties of the illuminator determine the influx, which is the radiant flux
projected by the illuminator onto the referen
...