ISO 15368:2021 provides rules for the measurement of the spectral reflectance of plane surfaces and the spectral transmittance of plane parallel elements using spectrophotometers.
This document only applies to measurements of the regular transmittance and the regular reflectance; it does not apply to those of the diffuse transmittance and the diffuse reflectance.
This document is applicable to test samples, which are coated or uncoated optical components without optical power.
