Scale75 Acrylic Retarder (60 ml.) Is used to extend the drying time of acrylic paint, also called drying retarder. Mix a few drops of Acrylic Retarder with the color or dip a brush from the retarder medium directly onto the pallet. It can be used for the "wet-in-wet" (wet-on-wet) technique and helps to form a sheet on the paint.