A "sketch" usually implies a quick and loosely drawn work, while related terms such as study , modello and "preparatory drawing" usually refer to more finished and careful works to be used as a basis for a final work, often in a different medium, but the distinction is imprecise. Underdrawing is drawing underneath the final work, which may sometimes still be visible, or can be viewed by modern scientific methods such as X-rays. Most visual artists use, to a greater or lesser degree, the sketch as a method of recording or working out ideas. The sketchbooks of some individual artists have become very well known,  including those of Leonardo da Vinci and Edgar Degas which have become art objects in their own right, with many pages showing finished studies as well as sketches. The term " sketchbook " refers to a book of blank paper on which an artist can draw or has already drawn sketches. The book might be purchased bound or might comprise loose leaves of sketches assembled or bound together.
Don Quixote Throughout his career Picasso would vary the amount of detail that we would use in his sketches, from the simple pencil drawings of his favourite animals, all the way up to the elaborate artworks like Vanquished Minotaur, Female Bullfighter I and Bullfight The more detailed works would often be completed as etchings, a large collection of which are now in the possession of the Museum of Modern Art in New York. The extraordinary productivity of Picasso has ensured that his original drawings are well spread right across the world enabling so many to get to see them in person. Alongside Picasso, other painters remembered fondly for their raw drawing skills would be the likes of Michelangelo , Gustav Klimt , Egon Schiele and Rembrandt. Portrait of Igor Stravinsky and Erik Satie, both , were charming line drawings which remind many of the work in the s and s of David Hockney.