A pencil is an implement for writing or drawing, constructed of a narrow, solid pigment core in a protective casing that prevents the core from being broken or marking the user’s hand. Pencils create marks by physical abrasion, leaving a trail of solid core material that adheres to a sheet of paper or other surface. They are distinct from pens, which dispense liquid or gel ink onto the marked surface.
A line drawing is the most direct means of expression. This type of drawing without shading or lightness, is usually the first to be attempted by an artist. It may be somewhat limited in effect, yet it conveys dimension, movement, structure and mood; it can also suggest texture to some extent.
Line gives character but shading gives depth and value-it is like adding an extra dimension to the sketch.