It is not recommended to draw with ink on vellum because it is difficult to erase. Tracing paper is much too light and flimsy and, as a result, tears and rips easily. However, the sturdiness of both vellum and Mylar enables numerous copies to be made from them. The decision as to which is best normally depends on the skill level of the design staff, available computer hardware and software, and budget. Vellum is generally cheaper than Mylar and slightly lighter in weight. One caution: Refrain from using tracing paper to draw the base sheet or base map. The base sheet and base map can be produced with a computer graphic program or drawn by hand. By comparison, Mylar or “drafting film” is a thin transparent plastic film used when either pencil or ink is the chosen medium for drawing. Vellum is a semitransparent paper used primarily when pencil is the chosen medium for drawing. Pencil smears less on vellum than on Mylar because the lead of the pencil is embedded more in the texture (called tooth) of the vellum.