The regulatory push towards a more sustainable coatings industry has driven the switch from solvent-borne to water-borne paints. One of the resulting technical challenges is how to gain greater control over the drying and film-forming process of paint dispersions, which has been a matter of intense investigation in recent years. Advanced analytical methods and imaging techniques have been used to gain insights into the mechanisms driving the film-forming process and to identify factors which influence open time [1]. Regardless of existing sophisticated analysis, we still see the need for a simple and easily accessible method which allows for ...