In contrast to imaging optics diffusors are typically used to achieve homogeneous luminance distributions for display and lighting applications. For example, LEDs are nearly point sources and therefore optical beam shaping components are needed. Optical diffusors in reflection and transmission are commonly used for additional luminance homogenization. However, a detailed quantitative understanding and numerical description of their optical performance are very unconfident or still unclear. In this contribution we focus on volume diffusors and present results on three types of particle-matrix-material combinations. The measured straylight distributions are compared to theoretical predictions and show good agreement. From these results optimized material parameters can be derived in order to get improved volume diffusers for tailored luminance distributions.