ISO TS 20793:2019 pdf free

ISO TS 20793:2019 pdf free.Photography一Lenticular print for changing images一Measurements of image quality
For the standard conditions, hemispherical ilumination shall be applied. The illumination spectra shall be a stable and spectrally continuous broadband visible light source, for example, an incandescent lamp defined as CIE Standard lluminant A.
The light reflected from the lenticular print shall be measured. lluminant D50 shall be applied. The following requirements are given for measurement instrument:
a) The spectroradiometer shall be capable of measuring spectral radiance over at least the 380 nm to 780 nm wavelength range, with a maximum bandwidth of 10 nm for smooth broadband spectra.
Care shall be taken to ensure that the LMD has enough sensitivity and dynamic range to perform the required task. The measured LMD signal shall be at least ten times greater than the dark level (noise floor) of the LMD, and no greater than 85 % of the saturation level.
b) The LMD shall be focused on the image plane of the print and aligned perpendicular to its surface,unless stated otherwise.
c) The relative uncertainty and repeatability of all the measuring devices shall be maintained by following the instrument supplier’s recommended calibration schedule.
d) The recommended measuring distance is between 35 cm to 60 cm. The measuring distance shall be noted in the report.
where Rstd is the calibrated luminous reflectance factor for that measurement configuration. When the illumination configuration is a uniform hemispherical illumination, then Rstd is equivalent to luminous reflectance Pstd. The luminous reflectance value associated with the standard is only valid for the hemispherical illumination in which it was calibrated. If it is used with a directed source at any angle, there is no reason to expect that the luminous reflectance value will be the correct luminous reflectance factor value for that ilumination configuration or spectra.
When making specular measurements, the detector is focused on the virtual image of the source.Black glass can be considered as a front surface mirror that has a low specular reflectance of between 4 % and 5 %. A black glass standard can be helpful when the measurement geometry does not allow measuring the source luminance directly, but only by using a mirror. The low specular reflectance of black glass allows measuring the source luminance at about the same order of magnitude as the reflection measurement.ISO TS 20793 pdf free download.