BS ISO 17221:2014 pdf free

BS ISO 17221:2014 pdf free.Plastics一Determination of image clarity (degree of sharpness of reflected or transmitted image)
For the measurement ofimage clarity, a lamp iluminates the narrow source aperture-slit. The collimating lens projects a parallel beam upon the specimen. The image is either reflected from or transmitted through the specimen, as appropriate. The image is received by the de-collimating lens and focused upon the optical mask. The light passing through the optical mask is received by the light receptor. This resultant signal is processed yielding image clarity values.
Light source and spectral response. The light source and the photometer shall be used in conjunction with a filter to provide an output corresponding to the photopic standard luminous efficiency V, which is identical to the colour-matching function y specified in ISO 11664-1, under CIE standard illuminant A as specified in ISO 11664-2. The output of the photodetector shall be proportional to the incident flux, to within 1 % of the incident flux, over the range used. The spectral and photometric characteristics of the light source and photometer shall be kept constant during measurements.
Optical mask, consisting of opaque and transparent lines having the same width and spacing. Six different groups of lines having different widths are utilized. An optical mask is illustrated in Figure 1.Table 1 gives the dimension for the lines of the optical mask.
Geometry (for reflection measurement). The normal geometry is 45*:45°. The 60°:60° may be used if agreed upon between the interested parties.
NOTE The 60°:60° geometry may be used depending on the surface structure of the specimen for conforming the visual assessments.
Black glass standard, giving a constant light intensity when any of the five line widths of optical mask is used for passing light. The bottom level of the waves is defined as the standard zero level.The black glass standard surface used should conform to specifications such as given in ISO 2813.
Structure. A diagrammatic representation of the apparatus used for evaluation of image clarity in transmission is shown in Figure 2. Figure 3 shows a diagrammatic representation for reflection measurement of image clarity.BS ISO 17221 pdf free download.