Sun, YinlongWang, Qiqi2015-02-212015-02-2120081467-8659https://doi.org/10.1111/j.1467-8659.2007.01110.xThis paper presents a systematic study of light interferences at single thin films. Based on Fresnel s law, we have derived generic expressions of reflectance and transmittance for film interference, as well as specific expressions for free thin films and films coated on transparent or opaque objects. By combining film interference and volume absorption, we have obtained the reflectances and transmittances of film-coated thin objects such as ribbons. Illumination models for all interference cases of single thin films are presented, and they have been implemented and tested for various structures and materials.10.1111/j.1467-8659.2007.01110.x1607-1631