Controlling the mechanical properties and stability of foams is both an everyday and an industrially important problem. A simple and remarkably effective technique for increasing foam stability consists in adding small solid particles. When the foam is created, these grains become trapped in the thin liquidfilms separating the bubbles, which gives the foam remarkable properties: slower drainage, higher mechanical resistance. Crucially, the particles are capable of redistributing the liquid within the film over time, by sucking liquid towards them. Such capillary forces could even reverse the usual drainage process, leading instead to a thickening of the film with time — the opposite of what occurs for a clean, particle-free film. In this internship, we want to evidence, for the first time, this phenomenon. We will study how granular rafts - composite objects formed by a large number of particles at the surface of an horizontal soap film - absorb the liquid from a reservoir.