Print Email Facebook Twitter Effects of inter-reflections on the correlated colour temperature and colour rendition of the light field Title Effects of inter-reflections on the correlated colour temperature and colour rendition of the light field: Inter-reflections and effective colour rendition Author Yu, C. (TU Delft Human Information Communication Design) Wijntjes, M.W.A. (TU Delft Human Information Communication Design) Eisemann, E. (TU Delft Computer Graphics and Visualisation) Pont, S.C. (TU Delft Human Information Communication Design) Date 2022 Abstract In everyday scenes, the effective light (the actual light in a space) can be defined as a complex light field, resulting from a mixture of emissive light sources and indirect mutual surface (inter-)reflections. Hence, the light field typically consists of diffuse and directional illumination and varies in spectral irradiance as a function of location and direction. The spatially varying differences between the diffuse and directional illumination spectra induce correlated colour temperature (CCT) and colour rendition variations over the light fields. Here, we aim to investigate the colourimetric properties of the actual light, termed the effective CCT and colour rendition, for spaces of one reflectance (uni-chromatic spaces). The spectra of the diffuse light-field component (light density) and the directional light-field component (light vector) were measured in both physical and simulated uni-chromatic spaces illuminated by ordinary white light sources. We empirically tested the effective CCT and colour rendition for the light density and the light vector, separately. There were significant differences between the lamp-specified CCT and colour rendition and the actual light-based effective CCT and effective colour rendition. Inter-reflections predominantly affected the CCT and colour rendition of the light density relative to the light vector. Treating the diffuse and directional light-field components in a linear model reveals the separate influences of the light source and scene. These effects show the importance of a 3D version of colour checkers for lighting designers, architects or in general computer graphics applications, for which we propose simple Lambertian spheres. To reference this document use: http://resolver.tudelft.nl/uuid:57bded53-3d4f-412d-8995-f132bd6f97e2 DOI https://doi.org/10.1177/14771535221126902 ISSN 1477-1535 Source Lighting Research and Technology, 55 (7-8), 772-793 Part of collection Institutional Repository Document type journal article Rights © 2022 C. Yu, M.W.A. Wijntjes, E. Eisemann, S.C. Pont Files PDF 14771535221126902.pdf 3.65 MB Close viewer /islandora/object/uuid:57bded53-3d4f-412d-8995-f132bd6f97e2/datastream/OBJ/view