He discussed J. W. Turner's method of cool and warm colours in creating a composition. One series that was brought to attention was the series Turner created of a specific mountain, the Rigi, in Switzerland. The Blue Rigi shows a cool mountain against a warm sky while the Red Rigi shows a warm mountain against the cool, see link.
As Smibert discussed this process I played around with the formula based on a rock formations located down the Western Australian south coast. Although my initial colour of the rock is warm against a warm sky I've accented the rock with cool blues and echoed cool blues in the sky.
The overall effect is a slightly shimmering colour contrast.