Raimo Silvennoinen received the PhD degree in physics from the University of Joensuu in 1990. He joined the Faculty of Natural Sciences at the University of Joensuu in 1975, where he is currently an assistant professor in physics. Dr Silvennoinen is interested in optics and optoelectronics, optical metrology and their applications. He is co-author for more than 85 original articles in refereed journals. He is also member of the Finnish Optical Society (FOS), OSA, SPIE, and AAAS.Professor Peiponen has written 3 books related to optical spectroscopy. He has contributed to the fields of industrial optical inspection, optical spectroscopy and optical properties of nano structures. In addition to original papers on optics he has contributed didactical optics.Kari Myller received the Ph.D degree in physics in 2004. The subject of his research was gloss measurement. At the moment he is researcher in InFotonics Center Joensuu and also performs duties of managing director of MGM-Devices Ltd. MGM-Devices is a high-tech company in the field of optical quality control. The main goal of MGM is development and fabrication of a modern diffractive optical element based glossmeter.