This document covers the determination of the total luminous transmittance, in the visible region of the spectrum, of planar transparent plastics and substantially colourless plastics, using a double-beam scanning spectrophotometer. This document cannot be used for plastics which contain fluorescent materials.
This document is applicable to transparent moulding materials, films and sheets not exceeding 10mm in thickness.
NOTE1 Total luminous transmittance can also be determined by a single-beam instrument as in ISO13468-1.
NOTE2 Substantially colourless plastics include those which are faintly tinted.
NOTE3 Specimens more than 10mm thick can be measured provided the instrument can accommodate them, but the results cannot be comparable with those obtained using specimens less than 10mm thick.