Observations on the evolution of the contour line in animated characters. Sahra Kunz CITAR – Centro de Investigação em Ciência e Tecnologia das Artes, Escola das Artes, Centro Regional do Porto da Universidade Católica Portuguesa, Rua Diogo Botelho, 1327, 4169-005 Porto, Portugal skunz@porto.ucp.pt Abstract. From the viewpoint of Drawing Contour constitutes the line that defines and contains the shape and volume of any drawn object. From a perceptual standpoint, it is what distinguishes a shape from its background. In the past hundred years the contour line that defines animated characters has mutated through diverse styles, many of them a direct consequence of the technologies available at the time of their creation. Technological breakthroughs in animation such as Rotoscopy, Celluloid Cels, Digital Ink and Paint or Cel Shading led to the evolution of the contour line, influencing the style and appearance of cartoon characters. How can one expect the contour line to develop, in times when the character of this line no longer has to rely on the particular drawing styles of the animator, but can be created semi-automatically through software extrapolation? Keywords: Animation, Cartoon characters, Drawing, Contour line 1. Contour and Outline: The term contour can be used both in the knowledge areas of visual perception and of drawing. In visual perception, the term edge defines a discontinuity of a surface, or the passage from one object to another. It does not depend on the observer's viewpoint because it refers to specific characteristics of the object, which define it as a three- dimensional entity. In the study of drawing, the definition edge can be transposed either into a contour or into an occluding contour. The first term defines the outline of the object as seen by an observer from a certain viewpoint. This contour is specific to the point from which the object is being observed, and defines its relationship to the background, or to the other objects in a scene or group of objects. When referring to an occluding contour, one is referring to a contour that partially obstructs the view of an object that is further to the back. Outline is a term commonly used in drawing, and refers to the boundary the mark creates on the drawing surface, containing a shape, color or shading - the outline may or may not correspond to the contour or occluding contour. If the artist aims to create a realistic type of drawing, the outline will correspond exactly to the contour of the object. [1] In order to better distinguish between contour and outline as far as drawing as concerned, one can turn to the definition proposed by the artist Kimon Nicolaides: “‘Contour’ is commonly defined as ‘the outline of a figure or body’ (…) We think of an outline as a diagram or silhouette, flat and two-dimensional. (…) Contour has a three-dimensional quality; that is, it indicates the thickness as well as the length and width of the form it surrounds.” [2] Following this definition, the word contour will be used to describe the line surrounding animated characters. Both visual perception and drawing share a notation system, whose elements are called junctions. Their correct use in a line drawing is what represents depth when no