Transmittance and reflectance are closely related concepts. Reflectance is defined as the ratio of collected reflected radiant power to incident radiant power. December 2018; DOI: 10.1007/978-3-319-96601-4_14. Deducing ink-transmittance spectra from reflectance and transmittance measurements of prints Mathieu Hébert and Roger D. Hersch Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Computer and Communication Sciences, 1015 Lausanne, Switzerland. Labsphere offers two standard products for reflectance and transmittance measurement, both products available in one of two reflective coatings. Transmittance is defined as a ratio of the intensity of incident light (I 0) to the amount of intensity passes through the object (I). Any ﬂux not reﬂected or transmitted is absorbed ( ). Conservation of energy requires that + + = 1. (2.5) By Kirchoff’s radiation law,22 the ﬂux emitted by a hot object must be equal to the amount absorbed by it; therefore, the emittance εof an object must be equal to . reflectance or transmittance of light through a sample medium. Due to conservation of energy, reflectance can have any value in the interval 0 to 1. The transmittance is denoted as T. Transmittance. The RT-060-SF and RT-060-IG sphere assemblies constitute our most basic reflectance measurement produ ct. ABSTRACT The color of prints is mainly determined by the light absorption of the inks deposited on top of paper. Reflectance and Transmittance for a Glass-to-Air Interface Parallel polarization Incidence angle, i 1.0.5 0 0° 30° 60° 90° R T Note that the critical angle is the same for both polarizations. And still, R + T = 1. Transmittance is the amount of ﬂux transmitted by a surface, normalized by the amount of ﬂux incident on it. Reflectance and Transmittance of Cholesteric Liquid Crystal Sandwiched Between Polarizers. 2.4.3 Reflectance and Transmittance. Reflectance and transmittance were measured as functions of wavelength with a Beckman model DK-2A spectroreflec-tometer,' a double beam ratio-recording spectrophotometer with an integrating sphere to capture diffuse light.