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1、BRITISH STANDARD BS 1384-1: 1985 ISO 5-1:1984 Photographic density measurements Part 1: Guide for terms, symbols and notations ISO title: Photography Density measurements Part 1: Terms, symbols and notations UDC 771.534.531 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 07:53:18 GMT+00:00 20
2、06, Uncontrolled Copy, (c) BSI BS 1384-1:1985 This British Standard, having been prepared under the direction of the Cinematography and Photography Standards Committee, was published under the authority of the Board of BSI and comes into effect on 28 June 1985 BSI 10-1999 First published August 1947
3、 First part revision as BS 1384-1 June 1985 The following BSI references relate to the work on this standard: Committee reference CPM/10 Draft for comment 79/62847 DC ISBN 0 580 14334 1 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Cin
4、ematography and Photography Standards Committee (CPM/-) to Technical Committee CPM/10 on which the following bodies were represented: British Institute of Non-destructive Testing British Kinematograph, Sound and Television Society British Photographic Association College of Radiographers Institute o
5、f Physics Ministry of Defence Photogrammetric Society Royal Photographic Society Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 07:53:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1384-1:1985 BSI 10-1999i Contents Page Comm
6、ittees responsibleInside front cover National forewordii 0Introduction1 1Scope and field of application1 2References2 3Definition of fluxes2 4Symbols3 5Measures of flux modulation3 6Coordinate system4 7Functional notation6 Bibliography9 Figure 1 Coordinate system for describing the geometric factors
7、 affecting transmission and reflection measures4 Figure 2 Coordinate system and angular conventions for describing distributions in terms of cones5 Figure 3 Schematic representation of influx geometry G, total propagated flux 9 and efflux geometry g (shown for the transmission case)6 Table 1 Measure
8、s of flux modulation3 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 07:53:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1384-1:1985 ii BSI 10-1999 National foreword This British Standard is one of a series of Parts which together constitute a rev
9、ision of BS 1384, first published in 1947 and confirmed in 1962, and has been prepared under the direction of the Cinematography and Photography Standards Committee. This Part is identical with the English-language portion of ISO 5-1:1984 “Photography Density measurements Part 1: Terms, symbols and
10、notations” published by the International Organization for Standardization (ISO). BS 1384:1947 defines terms and symbols and provides a method for measuring photographic transmission density only. The complete revision of this standard in four Parts will in addition cover reflection density. Termino
11、logy and conventions. The English text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following.
12、 Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. ISO 5-2 and the identical corresponding Part of BS 1384 are in course of preparation. CIE Publications No. 17 and No. 38, referred to in the text, are published by the Internat
13、ional Commission on illumination (Commission Internationale de lEclairage). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confe
14、r immunity from legal obligations. Cross-references International StandardsCorresponding British Standards BS 1384 Photographic density measurements ISO 5-3:1984Part 3:1985 Specification for spectral conditions (Identical) ISO 5-4:1983Part 4:1985 Specification for geometric conditions for reflection
15、 density Identical) ISO 31-6:1980BS 5775 Specification for quantities, units and symbols Part 6:1982 Light and related electromagnetic radiations (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 10, an inside back cover and a back
16、cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 07:53:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1384-1:1985 BSI
17、10-19991 0 Introduction The measurement of the transmission and reflection characteristics of objects and photographs is essential to the science of photography and optics. When light or other radiant energy strikes an object, it is either absorbed or propagated. Propagation may involve reflection,
18、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 whic
19、h 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 source to the receiver. The time rate of flow of radiant energy is called radiant flux, or simply flux. This International Standard provides metho
20、ds of describing 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 specimen to be measured, and the spectral sensitivity of the receiver must be given. If the refl
21、ection characteristics of the source or the receiver affect the measurement, as they do in transmission measurements by the opal glass method, they must be specified. The specimen area under consideration is defined by a sampling aperture, the dimensions of which may be important in some application
22、s and must be specified if the sample has appreciable non-uniformity. If the measurement is to quantify the way the specimen would modulate flux in a given practical application, such as viewing or contact printing, the geometric and spectral conditions of measurement must simulate those conditions
23、in the practical application. In most practical cases, the flux of interest is propagated by transmission or reflection, but at times some combination of these or other modes of propagation may be involved. In this case, the process is referred to by the general term “propagation”. Modulation is mea
24、sured and expressed as a dimensionless modulation factor which is equal to a ratio of fluxes; that is, the flux propagated in the directions and that part of the spectrum of interest divided by some reference flux. The reference flux may be the incident flux, the flux propagated through the system w
25、ith the specimen removed, or the flux propagated through the system when the sample is replaced by a reference standard. 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
26、as the negative logarithm to base 10 of the modulation factor. Since this International Standard identifies three modes of propagation (one of which is the general mode “propagation”), three kinds of reference flux and two mathematical forms, there are 18 different measures of modulation. Each of th
27、ese quantities is given a name and symbol. Each is defined as a ratio of fluxes or a logarithm of a ratio. Each kind of flux required for these definitions is given a name and a symbol. Previous standards have defined various types of optical density and have provided symbols for a few easily specif
28、ied types. Certain arrangements, which may be regarded as geometrically extreme cases, were specified in simple terms, such as diffuse or specular. These idealized extreme cases are never fully realized in practice, although they are often approximated. There has long been a need for a standard meth
29、od of specifying geometric conditions closer to practice, as well as the extreme cases. The system of specification in this International Standard provides for all cases, and permits a precise description of them 6. Most geometric arrangements used in photographic and other optical systems can be co
30、nveniently and adequately described in terms of uniform pencils of flux bounded by right circular cones. A point on the specimen is often irradiated by such a conic distribution, and the geometric form of the pencil of rays reaching the sensor is generally conic. The pupil of the eye, for example, s
31、ubtends a conic solid angle at a specimen point. In projection systems, the projection lens subtends a conic solid angle at the specimen point. This International Standard specifies a conic distribution by the half angle of the cone and the direction of its axis. A working knowledge of radiometry is
32、 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 and practice of radiome
33、try are well known and are fully described in the literature 1, it is considered unnecessary to provide a detailed specification of radiometric procedures in this International Standard. 1 Scope and field of application This International Standard establishes terms, symbols, notations and a coordina
34、te system to describe geometric and spectral conditions for the measurement of the degree to which a specimen modulates radiant flux, for applications in photography and radiometry. It primarily provides a system for describing methods of measuring or specifying the transmission and reflection prope
35、rties of photographic materials. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 07:53:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1384-1:1985 2 BSI 10-1999 2 References ISO 5, Photography Density measurements Part 2: Geometric conditions for transmission density1) Part 3: Spectral condi
36、tions1) Part 4: Geometric conditions for reflection density. ISO 31-6, Quantities and units of light and related electromagnetic radiations. CIE Publication No. 17 (E-1.1) 1970, International lighting vocabulary. CIE Publication No. 38 (TC-2.3) 1977, Radiometric and photometric characteristics of ma
37、terials and their measurements. 3 Definition of fluxes 3.1 influx adjective referring to the radiant flux incident on the specimen surface or sampling aperture 3.2 efflux adjective referring to the radiant flux emanating from the specimen or sampling aperture and evaluated by the receiver 3.3 radian
38、t flux, time rate of flow of radiant energy. It is denoted by the symbol with a lower case subscript to identify the particular flux 3.4 incident flux, i flux incident on the sampling aperture defining the specimen area on which the measurement is made 3.5 absorbed flux, a radiant flux absorbed by t
39、he specimen 3.6 propagated flux, Radiant flux propagated by the specimen in the directions and parts of the spectrum to be utilized in the measurement or application. Flux is propagated by transmission, reflection, refraction, diffraction, scattering, fluorescence, or some combination of these. 3.6.
40、1 total propagated flux, radiant flux propagated by the specimen in all directions and all parts of the spectrum. Similarly, one may refer to total transmitted flux, E, or total reflected flux 3.6.2 reflected flux, flux that emerges from the specimen surface on which the incident flux falls. This ma
41、y include fluorescent flux following absorption as well as flux propagated by reflection and/or scattering 3.6.3 transmitted flux, flux that passes through the specimen and emerges from a surface other than that on which the incident flux falls 3.6.4 reference standard propagated flux, e propagated
42、flux with a reference standard in place of the specimen 3.6.5 reference standard reflected flux, e reflected flux with a reference standard in place of the specimen 3.6.6 absolute reference reflected flux, A flux that would be reflected by a perfectly reflecting and perfectly diffusing material in p
43、lace of the specimen 3.6.7 reference standard transmitted flux, e transmitted flux with a reference standard in place of the specimen 3.6.8 extraneous flux (stray flux), x flux reaching the receiver without having followed the instruments prescribed optical path 3.7 aperture flux, j flux emerging fr
44、om the sampling aperture in the directions and parts of the spectrum to be utilized in the measurement or application with the specimen removed, but the remainder of the system undisturbed, as when a slide is replaced in a projector by an empty slide mount 1) At present in stage of draft. Licensed C
45、opy: sheffieldun sheffieldun, na, Fri Nov 24 07:53:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1384-1:1985 BSI 10-19993 4 Symbols The symbols defined or referred to in this International Standard are listed below for convenience and to encourage their use in the fields of photography and radiom
46、etry. For those concepts defined in the CIE International Lighting Vocabulary and referred to in this International Standard, the same symbols have been used. 5 Measures of flux modulation Terms, symbols and defining equations for various measures of flux modulation are given in the following table.
47、 Table 1 Measures of flux modulation aaabsorbed jaaperture iaincident apropagated atotal propagated areflected atotal reflected atransmitted Eatotal transmitted eareference standard Aaabsolute standard rrelative bcflux Dboptical density cpropagance bcreflectance bctransmittance Ppropagance factor Ra
48、bsolute reflectance factor Ttransmittance factor Sinflux spectrum, spectral power distribution of incident flux sspectral sensitivity of the receiver Vbcvisual spectral sensitivity or spectral luminous efficiency CIE ACIE standard illuminant A Ginflux geometry gefflux geometry half angle of right ci
49、rcular cone polar coordinate or colatitude angle polar longitude or azimuth angle Ebcirradiance spectral product (Ss) bcWavelength of radiant flux a Used as subscripts to define fluxes, angles, etc. b Symbols used in the International Lighting Vocabulary. c Symbols described in ISO 31. Arithmetic (modulation factor, m)Logarithmic (optical density, D) TermsEquationsTermsEquations TransmittanceTransmittancea densityD = log10 (2) ReflectanceReflectancea densityD = log10 (4) PropaganceP