Crossed polarization is a photographic technique that uses two polarizing filters: one placed over the light source and the other positioned between the subject and the lens. When applied to certain materials, this setup can reveal birefringent effects, producing coloured patterns that indicate areas of stress or strain. Crossed polarization is commonly used in scientific and engineering photography, as well as in architectural model studies, to visualise structural tensions and material behaviours that are otherwise invisible to the naked eye.