OPEN Acrylics feature uniquely relaxed working characteristics and a remarkable ability to resist skinning and remain wet on the palette during long painting sessions. Working time varies according to how thickly the material is applied. Thin applications ï¿?tack up,ï¿? allowing additional layers to be applied and blended. Thicker applications may be worked for hours. This 6-color set includes Hansa yellow opaque, Pyrrole red, quinacridone magenta, pthalo blue green shade, pthalo green blue shade and titanium white in 22ml tubes and an OPEN Application Guide.