Liquid coating involves spreading a liquid film containing a solute and then evaporating the solvent. When a defect such as dust is present, it can cause thickness gradients in the final deposit that can be visible to the naked eye. We have recently shown that the drying of liquid films of polymer solutions around a defect leads to the formation of relief on the final deposit. We believe that this relief is amplified by a coffee stain effect. The coffee stain effect corresponds to the accumulation of solute at the periphery of a drop drying on a solid substrate. In some cases, the contact line remains trapped, and then the solute accumulates at the contact line, leading to the formation of a solute ring at the end of the drying process. The proposed internship will involve gaining a better understanding of the formation of this relief, by inducing Marangoni effects to modulate it. The experimental techniques used will be optical imaging and interferometry.