Take a closer look at Warren Chang's technique in this demonstration from the April 2007 issue of American Artist.
The Thumbnail Sketch Using reference photos taken in the field, Chang did a 4"-x-6" pen-and-ink thumbnail sketch on paper to establish the composition and content of the scene.
The Color Sketch The artist spent a couple of days completing this 12"-x-16" oil sketch on canvas, which gave him all the necessary information he would need to transfer the image to a larger scale.
The Underpainting In this underpainting done in raw umber, Chang solved his drawing and compositional issues while also establishing the tonal values and mood.
THE COMPLETED PAINTING: Approaching Storm: Broccoli Harvest 2006, oil, 30 x 40. Collection the artist.
Building off the thumbnail sketch, color sketch, and the underpainting he already established, Chang used a limited palette—with the exception of some blue and green—-to complete this painting. “The blue of the sky was achieved using black and white,” Chang reveals, “and I arrived at the greens using mixtures of yellow ochre, cadmium yellow, and black.”