ISO 9416:2017 論文—光の散乱係数と吸収係数の決定（Kubelka-Munk理論を使用） | ページ 6

3.1

reflectance factor

R

ratio of the radiation reflected by a surface element of a body, in the direction delimited by a given cone with its apex at the surface element, to that reflected by the perfect reflecting diffuser under the same conditions of irradiation

Note 1 to entry: The ratio is often expressed as a percentage.

3.2

luminance factor (C)

R_y

reflectance factor (3.1) defined with reference to the visual efficiency function and the CIE illuminant C

Note 1 to entry: The visual efficiency function describes the sensitivity of the eye to light, so that the luminance factor corresponds to the attribute of visual perception of the reflecting surface.

Note 2 to entry: For computational purposes, the

3.3

single-sheet luminance factor (C)

R_y,0

luminance factor (C) (3.2) of a single sheet of paper with a black cavity as backing

3.4

intrinsic luminance factor (C)

R_y,∞

luminance factor (C) (3.2) of a layer or pad of material thick enough to be opaque, i.e. such that increasing the thickness of the pad by doubling the number of sheets results in no change in the measured reflectance factor

[SOURCE:ISO 2471:2008, 3.4]

3.5

opacity (paper backing)

ratio of the single-sheet luminance factor (C),R_y,0, (3.3) to the intrinsic luminance factor (C),R_y,∞ , (3.4) of the same sample

Note 1 to entry: The opacity is expressed as a percentage.

3.6

light-absorption coefficient

k

fraction of the spectral radiant flux diffusely incident on a differential layer within a material that is absorbed when the flux passes through the layer, divided by the thickness of the layer

Note 1 to entry: The flux referred to is a radiant flux across the differential layer.

3.7

light-scattering coefficient

s

fraction of the spectral radiant flux diffusely incident on a differential layer within a material that is reflected when the flux passes through the layer, divided by the thickness of the layer

Note 1 to entry: The flux referred to is a radiant flux across the differential layer.

Note 2 to entry: It is assumed that no reflection occurs at the boundaries of the material.

Note 3 to entry: In a two-flux system, the scattering coefficient is equal to the net transfer of flux from the stronger flux to the weaker flux in a differential layer within a material divided by the product of the thickness of the layer and the difference between the fluxes(see ISO 186).

3.8

light-scattering coefficient by reflectance factor measurements

s_y

<Kubelka-Munk method> coefficient calculated by application of the Kubelka-Munk equations to luminance factor data weighted with respect to the CIE illuminant C, obtained in an instrument having a specified geometry and calibrated in a specified manner, on the basis of grammage

Note 1 to entry:s_y is expressed in square metres per kilogram (m²/kg).

3.9

light-absorption coefficient by reflectance factor measurements

k_y

<Kubelka-Munk method> coefficient calculated by application of the Kubelka-Munk equations to luminance factor data weighted with respect to the CIE illuminant C, obtained in an instrument having a specified geometry and calibrated in a specified manner, on the basis of grammage

Note 1 to entry:k_y is expressed in square metres per kilogram (m²/kg).

Note 2 to entry: Definitions in 3.6 and 3.7 are strictly applicable to monochromatic light but for the purpose of this document, they apply to broad-band radiation. In research work, s_y and k_y can and should be determined at the relevant wavelength for the study concerned. As general descriptions of a given paper, they are defined here in relation to the V(λ) function and the CIE illuminant C.