Use this additive with WaterBorne PreBlended colors to extend drying time. It increases transparency when blending and washing colors. It helps to reduce paint forming a skin on the palette.  Cleans up with soap and water.
There are two ways to use it:
Lightly moisten the brush with Retarder before picking up paint.
Mix directly into colours beginning with a ratio of approximately 1 part Slo-Dri to 3 parts of color to delay the drying time of the paint. 
Too much Slo-Dri can cause adhesion problems with your paint layers!  We recommend you use not more than 10% to 50% Slo-Dri to paint.