Charcoal has been used for drawing since time immemorial. However, up to the Middle Ages it was used mainly for preparatory drawings, sketches and exercises since the soft line left by the charcoal on paper can easily be erased or whisked away. The development in the 15th century of suitable methods for fixing charcoal and making drawings executed in it permanent led to charcoal drawings being regarded as works of art in their own right. Drawing on the whole came to be more highly appreciated in the 15th century. To make charcoal, limewood, willow or boxwood is cut into thin sticks and charred. Flame black, developed around 1550 in Venice for use in carbon pencils, is initially an intense black like lampblack. Drawings made with such carbon pencils do not need to be fixed; however, impurities in the oil in flame black made it gradually fade and assume a brownish tinge. In more recent times other carbon pigments, such as pressed pulverised charcoal, have been used to make carbon pencils. In Germany, Albrecht Dürer was the first consummate master of the charcoal drawing, which he used in portraiture.