ISO 5-1:2009 pdf free download – Photography and graphic technology一 Density measurements一 Part 1: Geometry and functional notation.
8 Functional notation
8.1 General
Functional notation provides a means of denoting the measured quantity, 1, and the parameters on which it depends. The symbol for the quantity is followed by the symbols for the various parameters (or their values in a specific case) in parentheses as:
where
G is the illuminator geometry;
S is the spectral power distribution of the influx;
g is the receiver geometry;
s is the spectral responsivity of the receiver.
The illuminator and receiver functions are separated by a colon. The geometric and spectrai conaiuons are
separated by semicolons. The geometric parameters introduced in 8.2 are separated by commas.
8.2 Geometric conditions
8.2.1 General
For both the illuminator and receiver, the geometric conditions are denoted by the type of geometry, the direction of the axis, the cone half-angle, and the diameter of the region. qz A complete description of the geometry with the functional notation includes all of these parameters. However, for ease of use and comprehension, some of these parameters can be omitted from the functional notation and instead be included in a text description of the geometry.
8.3 Spectral conditions
8.3.1 Illuminator
The spectral power distribution of the influx is a function of the source and the optical elements of the director. Many spectral power distributions of interest in photography and graphic arts are satisfactorily represented by distribution temperatures in Kelvin. Others can be specified by symbols for certain standardized sources, such as CIE standard illuminant A, or fluorescent lamps such as F-il. If the influx is limited to a narrow wavelength band, it may be denoted by its central wavelength. If other spectral power distributions are used, a symbol shall be assigned and the spectral power distribution shall be specified.
8.3.2 Receiver
The spectral responsivity of the receiver includes not only the responsivity of the detector, but also the optical elements of the collector.
The spectral responsivity can be denoted by symbols for a standardized spectral responsivity function such as for visual, P2 for the standard sensitivity of commonly used photographic papers, ‘S-4” for a
photomultiplier tube, or other such designators. If the spectral responsivity is limited to a narrow wavelength band, it may be denoted by its central wavelength. The general symbol for such a narrow band is 1” (lower case L). If other spectral responsivity functions are to be used, a symbol shall be assigned and the spectral responsivity specified.
8.3.3 Spectral product
The product of the influx spectrum, S, and the spectral responsivity of the receiver, .c, at each wavelength, is a function of wavelength and is called the spectral product, 17. of the instrument.
In principle, if the object being measured or optical elements of the instrument do not fluoresce or otherwise radiate, S and .c can be allowed to deviate from the specified spectral functions, if the combination provides the same spectral product as would be obtained with the two specified functions. A filter in the receiver might be designed to compensate for a deviation of the influx spectrum from the specified function. Such deviation is not generally permissible if appreciable fluorescence is found in the object or the optical components. If the object is fluorescent, the measured value of modulation depends on the influx spectrum, which should not be allowed to deviate from the specified spectral function.