Dextrin is a starch product that is dissolved in water to form a liquid binder. As this product is sensitive to decay it is necessary to add a preservative. Dextrin is the binder of Talens Gouache extra fine and of the other quality poster paints. A special property of a dextrin solution is thixotropy. If we leave the paint alone it will automatically thicken. Through movement (stirring or painting) the paint becomes thinner again and will easily spread out.