ISO 15368:2001

Optics and optical instruments - Measurement of reflectance of plane surfaces and transmittance of plane parallel elements

This International Standard gives rules for the measurement of the spectral reflectance of plane surfaces and spectral transmittance of plane parallel elements using spectrophotometers over the spectral range to 190 nm to 25 μm.

The transmittance τ and the reflectance ρ of optical components are generally divided into two parts as follows:

τ = τ_r + τ_d

ρ = ρ_r + ρ_d

where

τ_r is the regular transmittance;

τ_d is the diffuse transmittance;

ρ_r is the regular reflectance;

ρ_r is the diffuse reflectance.

This International Standard applies only 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 International Standard is applicable to test specimens which are coated or uncoated optical components without optical power.