Sketching for Painting
Sketching on location is a useful way of recording your immediate response to a subject, and it can capture feelings and thoughts far better than any camera. A sketch enables you to focus on the essential features, and it records the energy of a subject that you might want to develop more fully in a painting. Painters also use sketching as an information-gathering exercise.
While photography is an efficient and useful tool, a sketch has certain advantages. You are using your two eyes to observe the subject, so the information you record in a drawing conveys the sense of three dimensions, while a camera, depending on lighting and a host of other factors, can often make things look flat. Later in the studio, with only a photographic reference, it can be difficult to recapture the sense of depth that you felt in the original scene. A drawing of a carefully observed scene can help you rediscover the scene's many characteristics. Carelessly used zoom lenses can result in distortion, and it can be very frustrating trying to draw from a photograph that puts vertical buildings in acute perspective. An on-the-spot drawing is a valuable resource that can give you a great deal of useful information.
If you are a painter, you probably want to include a small set of color or watercolor pencils, or a field watercolor box, in your sketching kit. This will enable you to record at least an approximation of the colors for later painting. Alternatively, you can simply note brief descriptions of color. Some painters even develop their own code of abbreviations for longer color names. You might like to paint a color key with a range of hues for common mixes, with some sky blues, greens, grays, and browns, depending on your favorite subject. This will help you identify which specific shade to use. Simply number them and indicate the number on your sketch.
The added bonus of using sketches as the basis for painting is that, for some reason, a sketch encourages you to use the information creatively, while a photograph can often be very binding. Its assertion of realism seems to demand that you are faithful in representing every surface detail, while a sketch serves as a reminder of something seen, but leaves you free to continue to reinvent and interpret it.