Winsor & Newton Professional Acrylic Flow Improver increases the flow of acrylic colours allowing the application of areas of flat, even colour without changing colour strength. It is also effective for hard edge painting techniques, staining and water colour techniques. It maintains the stability of the colour from wet to dry when used with Winsor & Newton professional acrylic and slightly slows drying, so colours will remain usable slightly longer when mixed with this medium.

To dilute colour significantly it is recommended to use flow improver with water in ratio 1:20 as this preserves the integrity of the paint film, ensuring the pigment remains sufficiently bound. Under-bound colour can appear blotchy, may become brittle or not adhere to the canvas well, all issues which will be avoided with Flow Improver.