Surfactant-silica self-assembly processes have been extensively studied since the discovery of M41S mesoporous materials in 1992. Mesoporous silicate films can be grown from acidic solutions at the air-water or solid-water interfaces. The film grows after a characteristic ¿induction period¿ of some hours followed by rapid assembly of films producing Bragg diffraction peaks. The assembly process relies on the mediating capacity of the anions present to form neutral ion assemblies of the form Si+- Anion--Surf+. There are two main proposals to describe the film formation process. It has been observed that the mechanism varies depending on solution concentration and surfactant:silica ratios. This work will use contrast variation to highlight aspects of film assembly and use INTER to be able to follow the kinetics in real time, thereby enabling a detailed study of the induction period.