Freshly painted façades are open to weather influences, particularly in spring or autumn, when temperatures during painting more easily fall below the dew point [1]. Latex paint's film curing process becomes slower under these conditions, making the paint susceptible to humidity. If the binder film has not sealed the paint surface completely, condensed water can mobilise water-soluble paint ingredients, which then migrate to the surface. As the condensed water evaporates, the concentrated residues appear as stains, gloss patterns or snail trails. It is still not fully understood which ingredients are extracted, but surfactants are suspected to be a main contributor, ...