One of the techniques I have experimented with recently is poured acrylic ink on raw canvas. Morris Louis was probably the artist best known for pioneering this.
For my series on Climate Change, poured ink is the perfect medium to convey the feel of sea level rise, as the ink drenches the canvas and creates waves and eddies of color, as if swirls of ocean water were engulfing the viewer. To achieve this effect, you have to first treat the canvas with a liquid that breaks down the sizing and allows the ink to sink into the fabric. Then you have to work quickly to achieve the best effect, pouring and tilting, brushing huge swashes of ink and letting one bleed into another, spattering alcohol across the surface like sea foam.
The beauty of this kind of piece is in its spontaneity and simplicity: just pure ink flowing on raw canvas, no lines drawn except those naturally created as one color combines with another. As you pour and tilt and drag the brush across the surface, a completely organic form takes shape, a serendipitous blend of pure colors, much like the sea itself.