Observational models of graphite pencil materials

This paper presents models for graphite pencil, drawing paper, blenders, an d kneaded eraser that produce realistic looking pencil marks, textures. and tones. Our models are based on an observation of how lead pencils interact with drawing paper, and on the absorptive and dispersive properties of ble nders and erasers interacting with lead material deposited over drawing pap er. The models consider parameters such as the particle composition of the lean, the texture of the paper, the position and shape of the pencil materi als, and the pressure applied to them. We demonstrate the capabilities of o ur approach with a variety of images and compare them to digitized pencil d rawings. We also present image-based rendering results implementing traditi onal graphite pencil tone rendering methods.