Soft leads, that is, leads in the 6B to 2B range, are well suited to freehand
drawing. They tend to be thick in core diameter and leave some graphite
residue. Illustrations in soft lead tend to smear easily. Smearing and
smudging are creative options with soft leads. Use kneaded erasers to bring
out illustration highlights. When used on paper with pronounced grain or
tooth, soft leads appear granular and black. Soft lead pencils are brittle and
require more frequent sharpening than hard leads.
Leads in the range of B to 3H are medium hard leads. Ideal for general
purpose layout work, they are dense enough to leave an image and easily
erased. Graphite residue is minimal and the illustration has a light sheen to
Technical drawing and drawings that require a high degree of precision are
done by hard-leaded pencils in the 4H to 6H range. Hard-leaded pencils
have small diameter cores and hold points longer than soft leads. The lines
appear light and have a high sheen. Heavy pressure on hard-leaded pencils
creases the paper and is difficult to thoroughly erase.
Humidity affects the graphite core of lead pencils. On dry days, the pencil
leaves more dust or residue than on days of high humidity. On damp days,
pencil lines appear more black or dense. When continuing a pencil drawing
on a day of high humidity, you may have to select a lead that is a few
degrees harder than the lead you would use on a dry day.
You may find that as you master the medium of the pencil, you may increase
the selection of pencil leads at your disposal.
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