Liquitex - Acrylic Effects Gel Additive - Slow-Dri Gel Retarder - 8 oz - Additives allow the artist to adjust the working properties of acrylic paint. They can be used to increase the flow, the opacity, or the thickness, and more. While they do contain acrylic polymer for compatibility, they do not contain sufficient acrylic resin to act as a binder within the paint. Liquitex Slow-Dri Gel Reatarder Gel additive is an excellent choice when working in low humidity, or whenever increased workability and blending time of acrylic paints and mediums is desired. Will retain brushstrokes and add body to lower viscosity colors. Should not add more than 25% as there is no binder and it can weaken the stability of the paint film when too much is added.