In this scene, which depicts mainly sky, the whole sky area was first washed with clean water, then, without pause some weak Naples yellow was painted above the white central area, and gamboge slightly to the right and lower down. I immediately followed this with a mixture of French ultramarine and cadmium red across the top of the sky, down the sides and over the bottom, sitting back to watch these colours blend into each other.
At the critical moment when the whole sky began to dry I then applied a stronger wash of the same mixture across the top of the sky to form the darker clouds. There was much less water mixed into this application as I didn't want it to run, or cause unsightly runbacks. I then moved lower down to suggest the more shapely clouds, still using the stronger mixture, but by now the sky was drying rapidly, which suited me as I wanted these strands of clouds to hold their shape. At this point I also rendered the background forest with the same colour mix to retain a sense of unity and atmosphere, the last applications of this being a fairly dry mixture with little water. Experience will tell you how much water to use, as it also depends on the ambient drying conditions, so practice these wet-in-wet and fluid wash techniques on scrap paper to improve your skill with watercolour.
The painting is one of many from my new book, Skies, Light & Atmosphere, published by Search Press in June. It contains a wide variety of landscapes and how they are affected by these elements, including how to create interesting skies, the magic of shafts of sunlight, creative use of light and shadow, how to make the most of reflected light, losing mountain ridges in mist, and so much more. If you order the book from our website you can get a special offer with my new DVD on the same subject: this illustrates a few basic techniques for creating interesting skies, light and atmosphere, and has a wide selection of paintings and sketches with commentary on how the effects were achieved.