Since the binder of acrylic paint consists of acrylic resin particles and water, the paint layer will lose volume when the water evaporates from the paint. This means your brush strokes may become much more subdued once your paint has dried compared to when you first applied it.
If you want to keep that distinct brush stroke or palette knife mark, we recommend adding Amsterdam gel, heavy gel or extra heavy gel to your paint! The heavier versions of this gel can even help you create 3D volume differences and extremely thick layers.