Lead is made of a composition of substance and binder. The substance of a
pencil lead can be graphite, carbon, charcoal, lithographic grease, colored
pigment, wax, or pastel. The binder is relatively unimportant unless you are
writing on a slick surface. The selection of a pencil lead is a matter of
personal preference and creative intent; however, some guidelines do apply.
GRAPHITE: Graphite leads leave a dense black line with a shiny surface
that can reflect light or glare when photographed for reproduction. As
humidity increases, the lead softens and smears easily. In extremely dry
conditions, the graphite produces a dusty residue.
CARBON: Carbon pencils produce a dense, dull-surfaced black line that is
not affected by humidity to the same extent that graphite is. Carbon pencils
tend to smear if they are not freed by a commercial fixative.
CHARCOAL PENCILS: Charcoal pencils are not always found in a wood
casing. Charcoal is available as sticks and in powder form. Charcoal
produces a dense, dull black line.
LITHOGRAPHIC PENCILS: This pencil produces a dense black line which
tends to be greasy. Its primary purpose is marking lithographic plates, but it
also marks well on glass and plastics.
COLOR PENCILS: In a color pencil, pigment determines the color of the
line and binder determines whether it is water soluble or waterproof. Some
binders have a waxy binder that makes it difficult to erase or blend them.
PASTEL PENCILS: Once available only in stick form, pastels are now in
pencil form. The characteristics of the pastel pigment remain the same. In
the pastel, the pigment may be dry or oil-based. They leave a dull, chalky
line and come in many colors. Pastels more popular form is still in sticks