Conclusion
Color and visual appearance. Transparent, translucent, opaque

All the parameters of the microscopic level have thus been linked to those of the macroscopic level, whether in dilute, concentrated or pigmented media. The fundamental concept enabling this progression through several levels of description remains the complex dielectric function or, more generally, the complex dielectric tensor. Theoretical aspects of radiation scattering by a dilute medium made up of isolated, spherical, homogeneous particles with a complex refractive index were reviewed, and the limitations of Rayleigh theory were highlighted. Single, then multiple, scattering was approached from an angle that allows the connection between individual particle properties and those of the scattering medium as a whole (relationships between local, microscopic or mesoscopic constants and global, macroscopic constants of the medium). Application of the models presented, or of the many variants...