Liquitex-Slow Dri Fluid Retarder. A fluid that slows the drying time of acrylic paints and mediums by up to 40%. Mix into the paint when on the palette to slow the skinning-over of paint and increase blending time. This package contains 4oz/118mL of Slow- Dri Fluid Retarder. Conforms to ASTM D4236. Imported.