Digital sketches for a painting

For my recent series of acrylic paintings I have done my preliminary color sketches on the computer. Below are some of the interesting color variations that I developed on the computer in a short time, something that would be very time consuming if done using traditional mediums. My first sketch done using Photoshop Elements 3.0 on a Mac computer. This is a negative version of the same image. Another color variation. Having fun with color. Still another variation. On this version I changed the proportions of the first sketch to see what that would look like. The finished acrylic painting done on canvas.