Terms, symbols, coordinate system and functional notations for photographic density measurements
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National Standard of the People's Republic of China
Terms, syrmbols, coordinate system and function notations for photographic density measurements GB/T12823--91
This standard refers to and adopts the international standard IS0 5/1-1984 "Photography-Density measurement-Terms, symbols and notations". Subject content and scope of application
This standard specifies the terms, symbols, coordinate system and function notations for density measurement. This standard is applicable to photography, as well as related fields of photometry, colorimetry and optoelectronics. 2 Terminology
2.1 Luminous intensity (1) Luminous intensity The luminous intensity of a point light source in a given direction is the quotient of the luminous flux emitted by the light source in the solid angle element containing the given direction and the solid angle element. Its unit is candela (cd). It is expressed by formula (1). dt
2.2 Luminous flux (Φ) Luminous flux is a quantity derived from the effect of radiation on a standard photometric observer, with the unit being lumen (1m). 2.3 Luminance (L) luminance
The luminance of any point on the surface of the light source in a given direction is the quotient of the luminous intensity of the surface element containing the point in the given direction and the orthogonal projection area of the surface element on the plane perpendicular to the direction. It is expressed by formula (2). L=
ds.cosado.dAcoMa
wherein is the angle between the surface element normal and the given direction. Its unit is candela per square meter (cd/m2), 2.4 Illuminance (illuminance) illuminance
(2)
The illuminance of a point on the surface is the quotient of the luminous flux incident on the surface element containing the point and the area of the surface element, expressed by formula (3). F
Its unit is lux (Ix).
2.5 Radiant flux (e) radiant flux
Radiant energy passing through per unit time. Different flux types are distinguished by subscripts. Its unit is Watt (W) or Joule per second (J/s). 2.6 Illuminant
Approved by the State Administration of Technical Supervision on 1991-04-30 and implemented on 1992-03-01
:comGB/T 12823-91
Radiation with a definite relative spectral power distribution within the wavelength range that affects the color perception of an object. 2.7 Spectral concentration The spectral concentration of radiation is the quotient of the radiation X obtained in an infinitesimal interval around a given wavelength and the wavelength interval. It is expressed by formula (4).
2.8 Relative spectral power distribution relative spectral power distribution distribution.4
The spectral characteristics of radiation described by the functional relationship between the relative spectral concentration of some radiation bases (such as radiant power, irradiance, etc.) and the wavelength.
2.9 CIE standard illuminant ACIE standard illuminant The Planck radiator with a color temperature of T = 2 855.6 K is recommended by ACIE as the standard illuminant A.2.10 Photographic daylight An illuminator with a relative spectral power distribution of typical daylight with a correlated color temperature of approximately 5500K. 2.11 Distribution temperature distribution tcmpcrature When the ordinates of the Planck radiator and the radiator to be measured in the visible region are directly proportional or approximately proportional to the ordinates of the radiance spectral distribution curve, the temperature of the Planck radiator is called the distribution temperature of the radiator. Its unit is Kelvin (K). 2.12 Color temperature calorie temperature
When the radiation emitted by the Planck radiator is the same as the chromaticity of the radiator to be measured, the temperature of the Planck radiator is called the color temperature of the radiator to be measured. Its unit is Kelvin (K).
2.13 Correlated color temperaturecorrclatcd color tcmpcraturcIn the uniform chromaticity diagram, the color temperature of the point on the Planck radiator locus closest to the chromaticity of the radiator to be measured, its unit is Kelvin (K). 2.14 Chromaticitychtomaticity
The color quality of the color stimulus defined by the chromaticity coordinates or the main wavelength (or complementary wavelength) and its excitation purity. 2.15 Spectral responsivity of a filmspectral responsivity of a filmThe reciprocal of the spectral exposure radiation required to produce a certain density of the photosensitive film under different exposure lengths. 2.16 Weighted spectral responsivityweightedspectral tesponsivityThe value obtained by combining the relevant spectral functions recommended by international organizations (such as ISO and CIE, etc.) with the relative spectral responsivity of the photosensitive material to be measured.
2.17 Photographic responsivity (f) is the effective response of photographic materials to radiation, expressed by (5) )(ad
where: --relative spectral power distribution of radiation, S() --relative spectral responsivity of the material
() --relative spectral transmittance on the axis of the camera lens; ~ --the wavelength range to which the material is sensitive.
2.18 Visual density visual density
The transmission and reflection density measured by a detector whose spectral responsivity is consistent with CIE V(). 2.t9 Color integrating density color integrating density-(5
The transmission or reflection density measured by a test system with a certain spectral product. For example, H state, A state and T state densities are commonly used color integrated densities,
GB/T 12823-91
2. 20 Transmission printing density printing Ltransmission density When the film without spectral selectivity produces the same response on the printing material as the film to be tested, the density of the film is called the induced printing density of the film to be tested.
2.21 Projection density projection density A density measured under the condition that the angular distribution range of the incident radiant flux is equal to that of the transmitted radiant flux. 2.22 Micro-transmittance factor micro-transmittance factor The transmittance on a small area of the film.
2.23 Micro-density microdensity
The logarithm of the micro-transmittance factor taken to the base 10. 2.24
Radial flux ()ncldentux
The maximum amount of radiation incident on the sampling hole defined by the measured area of the sample. 2.25
Absorbed flux ()absorbedflux
The flux absorbed by the measured sample.
2.26 Transmitted flux ()propated Flux is the radiant flux transmitted by the specimen in certain directions and in the useful spectral region. This flux is transmitted by transmission, reflection, refraction, diffraction, fluorescence or a combination of them. Total transmitted flux (d) total propagated flux 2.27
Radiant flux transmitted by the specimen in all directions and in all spectral regions. It may be the total transmitted flux, or the total reflected flux.bZxz.net
Transmitted flux (@,) Transmitted flux The flux that passes through the specimen and does not come out of the surface on which the incident flux falls. Reflected flux (also.) Reflected flux The flux that comes out of the illuminated surface of the specimen, which includes the flux transmitted by reflection and scattering. It may produce fluorescence with the absorption process. Reference standard transmitted flux (r) tereference standard propagated flux The flux transmitted by the reference standard at the same position as the specimen. 2.31
Reference standard reflected flux (more) referencc standard rcflected flux The flux reflected by the reference standard at the same position as the specimen. Absolute reference reflected flux (@)ahsolute reflectedflux2.32
The flux reflected by a perfectly diffuse reflector at the same position as the sample. Reference standard transmitted flux (g)referencestandardttansmittedflux2- 33
The flux transmitted by a reference standard at the same position as the sample. 2.34 Parasitic flux (@) Extraneous flux The flux that does not follow the optical path specified by the instrument to reach the detector. 2.35 Aperture flux (@,) Aperture flux The flux that comes out of the sampling hole in certain directions and useful spectral regions when the sample is removed but does not interfere with other parts of the system. 2.36 Transmittance The ratio of the transmitted flux to the incident flux, expressed by formula (6): Its unit is 1. t = /@,
2.37 Reflectance (p) reflectance
The ratio of the reflected flux to the incident flux. Expressed by formula (7). Its unit is 1. -(6)
2.38 Propagation ratio () propagation
GB/T 12823-91
The ratio of the transmitted flux to the incident flux. Expressed by formula (8). Its unit is 1. 0,/0
2. 39 Transmittance (T) transmittance factor The ratio of the transmission flux to the aperture flux. Expressed by formula (9). The total unit is 1. T =d/d
2. 40 Reflectance factor (R) reflectance factor The ratio of the reflection flux to the absolute reference flux. Expressed by formula 10), its unit is 1. R= @./@
2.41 Transmission factor P) Propagance factot The ratio of the transmission flux to the aperture flux. Expressed by formula (11). Its unit is 1. p@
2.42 Relative transmittance factor (T,) telative transmittance factor The ratio of the transmission flux to the transmission flux of the reference standard. Expressed by formula (12). T, = 1,/@
2.43Relative propagation factor (1,)Relative propagation factorThe ratio of the transmission flux to the transmission flux of the reference standard. It is expressed by formula (13). P, - @/
2.44Transmittance factor density (D.)Transmittance densityThe reciprocal of the transmittance is taken as the logarithm to the base 10. It is expressed by formula (14). D, .- - lgt
2.45Reflectance density (D,)Reflectance densityThe reciprocal of the reflectance is taken as the logarithm to the base 10. It is expressed by formula (15). D,= -- igp
(12）
（13）
（15)
2.46Transmission density (n,) ptopagancedensityGB/T12823-91
The reciprocal of the transmission ratio is taken as the logarithm with the base 10. It is expressed by formula (16). D, = — lga
2.47Transmission density (D) transmission density The reciprocal of the transmission ratio is taken as the logarithm with the base 10. It is expressed by formula (17). D ±—RT
2. 4BReflection factor (Dr) reflcctilon dcnsityThe reciprocal of the reflection factor is taken as the logarithm with the base 10. It is expressed by formula (18). Dx = -
2.49Transmission density (p,) propagationdcnsityThe reciprocal of the transmission factor is taken as the logarithm with the base 10. It is expressed by formula (19). D, =
2. 50Relative transmission density (v) relative ttansmission densityThe reciprocal of the relative transmission factor is taken as the logarithm with the base 10. It is expressed by formula (20). D, Igt,
2.51Relative reflection density (R) rclativcreflectiondensityThe reciprocal of the relative reflection factor is taken as the logarithm with the base 10. It is expressed by formula (21), D
2. 52Relative propagation density (P,) relative propagation dcnsityThe reciprocal of the relative propagation factor is taken as the logarithm with the base 10. It is expressed by formula (22). Dr = lgP
2. 53 Verification scheme Technical provisions of the state for the verification procedures of measurement standards, recording standards of various levels and even working measuring instruments. 16)
（17）
(18）
+（20）
.{21）
（222
Verification scheme of measuring instrument for diffuse trans.missionvisualdensity
This verification scheme stipulates that the national standard of diffuse trans.missionvisualdensity is calibrated by the working curve calibration method. The second standard is calibrated by the true reading method. The black and white standard density film is then calibrated by the direct reading method. The measurement range is 0.4; the uncertainty of the standard density film is 0.005~0.010),
2. 55 Standard step density tablets photographic step density tablets GB/T 12823—91
A standard made of photographic film or photographic paper after exposure, development and dicing, with density values changing in steps with length. Standards made of film are used to calibrate black and white and color transmission densitometers. Standards made of photographic paper are used to calibrate black and white and color reflection densitometers.
2.56 Verification system for measuring instrument for diffuse transmission color intcgratingdensity This verification system specifies the national standard for color diffuse transmission integral density. The color density working standard is calibrated by the fixed-point calibration method. The A, Certification and T state mask standard films are calibrated by the direct reading method, and then the color working densitometer is calibrated by the direct reading method. The measurement range is 0.3D, and the uncertainty of the reference density film is 0.006~0.027. No. 3
In order to promote the use of unified symbols in photography and radiometry.This standard specifies some symbols commonly used in density measurements (see Table 1). The same symbols are used when defining quantities and angles. Table! Symbols for density measurements Coordinate system Absorption Total radiation Reflection Reflection factor Spectral responsivity of detector Geometrical conditions of outgoing flux Irradiance Wavelength of radiant flux Absolute standard Optical density Incident Total transmission Transmission ratio Photometric responsivity Geometrical conditions of incident flux Azimuth or azimuth Transmission Reference standard Spectrum of radiant flux Crt Standard illuminator A
polar or elevation
total transmission
transmission
reflectance
relative
transmission factor
standard photometric observer
right circular cone half angle
spectral product
The reference system selected when determining the geometric pattern of the incident or outgoing flux is called the reference system. The coordinate system of the geometric factors that affect the degree of optical shielding and reflection is plotted in Figure 1. The XY reference plane of the coordinate system is selected on the measuring surface or right surface of the sample, and the origin of the coordinate is placed at the center of the area to be measured. The Z axis is consistent with the vector direction of the incident flux, that is, it is perpendicular to the reference plane. The angle between the light and the Y axis is called the pitch angle 9.
The elevation angles of incident and reflected rays should be measured from the negative Z-axis. The elevation angles of transmitted and transmitted rays should be measured from the positive X-axis. The azimuth angle of a ray is the angle measured in the XY plane, which is the angle measured counterclockwise from the positive X-axis to the projection of the ray in the XY plane. The azimuth of the ray is then given by the coordinates 8 and . Angle 8 is less than 360°, angle 8 is equal to or less than 180°, and is usually less than 90%. The indices of the ray angles correspond to the indices of the flux, that is, α for incident, β for reflected, and α for transmitted, as follows:
, , and
If the thickness of the specimen must be taken into account, the output flux distribution can use a second coordinate system with its origin set at a certain distance along the positive Z-axis corresponding to the thickness, that is, X=X, Y=, Z=Z-, and its angles are specified in a corresponding manner. In a system where the sampling hole moves relative to the sample, the standard direction of the hole movement should be consistent with the axis of the end direction. The sampling hole is called a drilling hole.
Because in most cases, the incident flux distribution and the detector responsivity distribution diagram can be fully described by a cone, the system is shown in Figure 2. It is an extension of Figure 1. The coordinate system is indicated in the figure. The end cone half angle of the flux beam and the receiver responsivity distribution is called K, and its subscripts are used in the same way as before. If more than two cones are reached, their numbers are indicated by subscripts, such as K and K, and K-90 is used to represent the angular distribution of the hemisphere. Satisfactory elements
Introduction
Figure 1 Coordinate system describing transmission and reflection geometric conditions 5 Function representation
5.1 Overview
GB/T12823
Figure 2 Cone and angle describing angular distribution Specifications Numerical representation is a tool for expressing the relationship between the measurable maximum and its related parameters. The symbol of the quantity is followed by the symbols of the various parameters, which are enclosed in parentheses. This notation allows the dependence of the transmission density on the measurement (or use) conditions to be expressed in the following form: D(s:gis)
Geometric conditions of the incident flux, i.e., the angular distribution of the orange illumination. Where t:t-
S—the spectral distribution of the incident flux.
Geometric conditions of the outgoing flux, i.e., the angular distribution of the efficiency of the receiving system relative to the origin 0. The system includes filters, lenses, integrating spheres, opal glass, or other optical elements. Spectral response, i.e., the spectral response of the detection system to the radiant flux from the sample (including filters, lenses, integrating spheres, opal glass, or other optical elements).
The incident and outgoing flux functions are separated by a first suffix. The geometric function is separated from the spectral function by a semicolon. The angular parameters of the geometric functions introduced in Section 5.2 are separated by commas.
5.2 Geometric description
The geometric conditions of the incident and outgoing fluxes are shown in Figure 3. The angular distribution of radiance and responsivity is represented by a variable length spike. This quantity represents the relative value at different angles, and its absolute value does not need to be known. A small part of the total transmitted flux Φ, represented in the figure, is collected by the detector, which is the measured transmission flux. This measured value depends on the responsivity distribution & (\,). For example, it depends on the responsivity distribution on the surface of the optoelectronic device, or on the way different ring zones of the lens collect and transmit the flux.
The coordinate system given in Figure 2 describes the geometric properties of the incident and outgoing fluxes. In actual situations, the geometric properties of the incident and outgoing fluxes can be described by the half-angle K of the right cone and the direction 9 of the cone axis, and all angles are in degrees. Although the arrows in the figure do not represent light, they represent vector distributions. The arrow on the illuminator shall represent the geometrical distribution of the incident flux, the arrow on the specimen shall represent the geometrical distribution of the total transmitted flux, and the arrow on the detector shall represent the geometrical distribution of the responsivity. KT
$-(8,)
at8,p)
Figure 3 Geometrical conditions of incident flux G, total transmitted flux, and outgoing flux 9 5.2.1 Single cone
In the case of a single positive cone, the function of flux is expressed as follows, G = K:,8, such that (incident)
=K,P. ,(Reflection
9=K8 (Transmission)
5.2.2 Vertical Condition
In many photographic applications, the specimen is illuminated vertically at the center and observed vertically. In the reflection case, the flux distribution is between the two circular chain axes with the cone axis perpendicular to the specimen, that is, §=e=0=0. If 0=0, the is uncertain, so for convenience they can be ignored. In most cases, the geometric conditions can be fully specified by an angle of the incident geometry and an angle of the exit geometry. For the transmission density, it is expressed as Dr (KS, K18). For example, if the incident flux is incident and obtained with an integrating sphere, it is expressed as Ds(90°;8 :,;8). When opal glass is used as a diffuse illumination or diffuse collection tool, there is a special case where the mutual reflection between the opal glass and the sample affects the measured density of the sample. A special representation should be adopted for this case. When opal glass is used in the illumination system, K, is a 90° opal. When opal glass is used in the collection system, K, is a 90° opal. The resulting transmission density should be expressed as D(90° opal:%1K,:s) and D(R90 opal).
When 8-0 and the range of Φ is given, this range is not referred to the axis of the cone, but to the azimuth of the distribution within the cone. This special convention is particularly useful when describing retroreflection measurements. 5.2. 3 Annular area
In some standard measuring systems, the flux is uniformly incident in the annular area between two coaxial cones, or on each of these two circular cones. 12823—91
The outgoing flux is collected uniformly between the cones. In this case, the reflection density is expressed as D(,~K:;S:K,ts) or Ds(K,S:Kp--Kpts).
5.2.4 Additive or subtractive zone
When an angle is considered to be formed by more than two continuous zones. It can be described by using the addition sign + "". For example, :~K + K~K. Similarly, the subtraction sign *=\ can be used to represent the subtraction zone, for example, 0°~360°—170°~190°. 5.2.5 Movement of the outgoing flux coordinate system
If a second coordinate system describing the outgoing flux is to be established at a distance of 100° from the source point on the axis, the distance 1 can be expressed between two stomach numbers according to Article 3, and this symbol group can be connected in the following form to replace the usual single number. Dr(K,S: A+ .;s)
5.3 Description of spectral conditions
5.3.1 Spectrum of incident flux
The spectrum of incident flux is a function of the light source and of the optical elements used to modulate the incident flux before the specimen. In photographic science, many useful spectral power distributions can be satisfactorily described by the distribution temperature (in K). Other standard light sources, such as CIE standard illuminant A, or illuminant P-11, can be specified by symbols such as: If the incident spectrum is nearly monochromatic:, it can be expressed in nm as the wavelength of a single particle.
If other spectral distributions are used, their symbols must be specified and the spectral power distribution must be given. 5.3.2 Spectral responsivity of detector
The spectral responsivity of the detector includes not only the responsivity of the photodetector device, but also the spectral response of any optical element that modulates the portion of the flux reaching the detector.
Some symbols can be used to represent the standardized spectral responsivity. For example, √ is used to represent vision, P: is used to represent commonly used photographic paper, and -4 is used to represent devices such as photomultiplier tubes. If the spectral responsivity is limited to a narrow spectral band, that is, it is nearly monochromatic, it can be represented by wavelength. The general symbol for narrow bands is. If other spectral response functions are used, their symbols must be specified and the spectral response function must be given. 5.3.3 Spectral product
The incident flux spectrum and the spectral responsivity of the detector. The product at one wavelength is a function of wavelength and is called the spectral product of the instrument. It is represented by the symbol II, and its meaning is II = 8·%. If the material or optical element to be measured does not fluoresce or otherwise radiate, it is allowed to separate S and * from the specified function, as long as the spectral product of the combined function is the same as the spectral product obtained using the two specified functions. The filters of the detection system may be used to compensate for deviations of the incident spectrum from the specified function. This is generally not permitted if the specimen or optical element is found to have detectable fluorescence. If the specimen fluoresces, the value of the modulation measurement will be related to the incident spectrum and the spectral product should be specified. 5.4 Reference standards
To indicate that a measurement is made relative to an actual reference standard rather than an ideal standard, the symbol of the reference standard is placed at the end of the parameter table and separated from the emission parameter by the symbol /, such as (G:19;8/e), or D (GS98/e). In photographic science, the most frequently used reference standards are thiosulfate, support or support plus fog, represented by the symbols Baso + "s\ and "bf\ respectively. Other standards may be given other special symbols and the appropriate common symbols are used. The value of the absolute reflection factor makes it easy to compare the results of measurements at different locations and times. That is, this value is measured with an ideal completely diffuse reflector as the reference standard. However, such measurements are almost always made relative to a practical standard, that is, the measured values are relative reflectance values, R. The absolute reflectance factor R of the sample is calculated from the relative reflectance factor R of the sample and the absolute reflectance factor R of the reference standard by the formula B,=R,×R. The absolute reflectance factors of some practical materials used as reference standards have been measured and published by the IfI National Metrology Laboratory.
5.5 Example of functional representation
The functional representation of the transmission density (M-90°CIEA: 10°V) means that the human radiation flux is uniformly distributed at all angles in the entire hemisphere and its spectral distribution is the CIE standard illuminant A. This representation also shows that the uniformly distributed flux within the half cone angle of 5° between the reading cone axis and the sample normal is evaluated by a detector whose responsivity is proportional to the standard photopic spectral light gauge efficiency function. GB/T 12823—91
The functional representation of the reflection factor R (40°～50°: CIEA: 5°V) means that the incident flux is uniformly distributed in all azimuths from 40° to 50° in elevation, and has the spectral power distribution of CIE illuminant A. It also indicates that the flux in all azimuths from 0 to 5 in elevation is uniformly evaluated by a detector whose responsivity is proportional to the standard photopic spectral luminous efficiency function. Additional notes:
This standard was proposed and coordinated by the China National Institute of Metrology. This standard was drafted by the China National Institute of Metrology, and the China Electrochromatic Science and Technology Research Institute and the First Film Factory of the Ministry of Chemical Industry participated in the drafting. The main drafters of this standard are Li Zaiqing, Shi Changgui, Jin Jiadong, Ji Jiaqi, and Tang Zhijian.
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