Paul Jenkins uses mainly acrylic paint and water to create his paintings, firstly he places the acrylic paint using an ivory knife on his unstretched canvas, then pour water over the acrylic to create an uncontrollable effect. Jenkins called his series 'Phenomena', as his painting appeared to have happened like a phenomena.
Here is Helen Frankenthaler physically getting herself onto the canvas and again pouring the paint onto the unstretched canvas. She's letting the paint do the work as she only guides the flow of the paint with a brush. Frankenthaler's main aim is to produce a piece of work that will be found a beautiful picture, not to produce that perfect landscape or sunset.