The sea painting in this demo was done with acrylics, on a canvas sized 46 x 122cm (18x48"), using a 5cm (2") brush. I chose a limited palette consisting of titanium white, raw umber, Prussian blue, and turquoise. While there are plenty of suitable sea color paints to choose from, these are my favorites (particularly Prussian blue, which is transparent when used for glazing and quite dark straight from the tube).
I started by painting in the cloudy sky, working wet-on-wet. Although I didn't sketch out a composition on the canvas, I did measure the canvas so that the sky would cover the top third of the canvas (see: Composition Class: Rule of Thirds).
Once I'd finished painting the sky, I let it dry before starting on the coastal hills which were to recede into the distance on the horizon. Once again I didn't sketch out the hills on the painting because I had a very strong image in my mind of how I wanted to do them and didn't feel a need. The hills are painted in a gray mixed from the raw umber, Prussian blue, and titanium white, with the proportions varied to produce a variety of tones.
The little bits of blue you can see on the foreground are where I minimally marked the direction for the intended shore rocks using some left-over blue on my brush from painting the sky. The two dark splodges on the bottom end of the canvas are where I wet it front and back to get two small dents out.
