A sketch (ultimately from Greek σχέδιος - schedios, "done extempore") is a rapidly executed freehand drawing that is not intended as a finished work. In general, a sketch is a quick way to record an idea for later use. Artist's sketches primarily serve as a way to try out different ideas and establish a composition before undertaking a more finished work, especially when the finished work is expen
sive and time consuming (as in the case of a large painting or fresco). Sketching sharpens an artist's ability to focus on the most important elements of a subject and is a prescribed part of artistic development for students. Dry media such as pencil or pastel are often preferred due to time constraints, but a quickly done watercolor study or even quickly modeled clay or soft wax can also be considered a 'sketch' in the broader sense of the term. Graphite pencils being a relatively new invention, the artists of the Renaissance could make sketches using the expensive method of a silver stylus on specially prepared paper (known as silverpoint), with results similar to a modern pencil sketch, or, more cheaply, using charcoal, chalk, or pen-and-ink. Contrary to popular belief, artists often use erasers when drawing; the eraser may be used to remove rough construction lines, or to soften lines for visual effect. The most commonly used eraser for pencil drawing is the kneaded eraser, which has a soft, sticky surface that enables the artist to lift the graphite or charcoal from the drawing surface without smudging. White plastic erasers can cleanly erase line work, but tend to smudge heavy shading. The sketchbooks of Leonardo da Vinci and Edgar Degas are two examples of many done by famous artists which have become art objects in their own right, although many pages show more thoughtful studies rather than true sketches. The ability to quickly record impressions through sketching has found varied purposes in today's culture. Courtroom artists are usually sketchers. Sketches drawn to help authorities find or identify wanted people are called composite sketches. Street performers in popular tourist areas often include artists who sketch portraits within minutes. A sketch method of reproducing photographs is done with a photographic enlarger in a dark room. The negative image is projected on the paper where the sketch is to be done. All the light shades are penciled until the paper is all the same shade.
