TÓTH, František: Investigation of light penetration through wood in dependence on its thickness and method of treatment on CNC machine. [Doctoral thesis]/ František Tóth – Technical University in Zvolen, Faculty of Wood Sciences; Department of Woodworking. – Supervisor: prof. Ing. Mikuláš Siklienka, PhD. – Zvolen DF TU, 2017 The aim of this thesis was to determine the relationship between light transmission through the wood and its thickness. The paper compares translucent properties in three different directions of fibers in the wood. Those are radial, tangential and longitudinal wood fibres directions. The paper examined maple samples produced by CNC technology, we have achieved thickness of the wood from 0.2 mm to 1.8 mm. We measured and analyzed values of the light diffusion, colour temperature and material thickness. The results in the paper show that there is a proven dependence between the thickness of the wood and its translucency. Furthermore, it has been found that wood as an anisotropic material has different diffusion properties in different fiber directions. The highest values were measured in the longitudinal direction of the fibers.