An integrating sphere functions as a light collector, providing diffuse illumination or measurement sources. The basic principle involves light entering the sphere through the sample port, reflecting multiple times off the highly reflective, Lambertian surface of the sphere, and scattering uniformly throughout the interior. Behind a baffled port, which is independent of the angular properties of the sample port, a fibre-optic cable collects the homogenized light signal and directs it to the spectrometer. The baffle plays a crucial role by preventing first reflections from entering the detection fibre, ensuring accurate light collection.