The Humble Pencil – Plumbago but where’s the Lead?

Pencils create marks by physical abrasion, leaving behind a trail of solid core material that adheres to a sheet of paper or other surface. They are distinct from pens, which instead disperse a trail of liquid or gel ink that stains the light colour of the paper by absorption.

Most pencil cores are made of graphite mixed with a clay binder which leaves grey or black marks that can be easily erased. The most common type of pencil casing is of thin wood, usually hexagonal in section but sometimes cylindrical, permanently bonded to the core. Similar permanent casings may be constructed of other materials such as plastic or paper. To use the pencil, the casing must be carved or peeled off to expose the working end of the core as a sharp point. Mechanical pencils have more elaborate casings which are not permanently bonded to the core.

History

As a technique for drawing, the closest predecessor to the pencil was Silverpoint until in 1565 (some sources say as early as 1500), a large deposit of graphite was discovered on the approach to Grey Knott’s from the hamlet of Sea Thwaite in Borrowdale parish, Cumbria, England. This particular deposit of graphite was extremely pure and solid, and it could easily be sawn into sticks. It remains the only large-scale deposit of graphite ever found in this solid form. Chemistry was in its infancy and the substance was thought to be a form of lead. Consequently, it was called plumbago (Latin for “lead ore”). Because the pencil core is still referred to as “lead”, or a “lead”, many people have the misconception that the graphite in the pencil is lead,

Around 1560, an Italian couple named Simonio and Lyndiana Bernacotti made what are likely the first blueprints for the modern, wood-encased carpentry pencil. Their version was a flat, oval, more compact type of pencil. Their concept involved the hollowing out of a stick of juniper wood. Shortly thereafter, a superior technique was discovered: two wooden halves were carved, a graphite stick inserted, and the halves then glued together essentially the same method in use to this day.

On 30 March 1858, Hymen Lipman received the first patent for attaching an eraser to the end of a pencil. In 1862, Lipman sold his patent to Joseph Reckendorfer for $100,000, who went on to sue pencil manufacturer Faber-Castell for infringement. In 1875, the Supreme Court of the US ruled against Reckendorfer declaring the patent invalid.

 

 

Types of Pencils.

 

Graphite pencils

These are the most common types of pencil, and are encased in wood. They are made of a mixture of clay and graphite and their darkness varies from light grey to black. Their composition allows for the smoothest strokes.

Solid graphite pencils

These are solid sticks of graphite and clay composite (as found in a ‘graphite pencil’), about the diameter of a common pencil, which have no casing other than a wrapper or label. They are often called “woodless” pencils. They are used primarily for art purposes as the lack of casing allows for covering larger spaces more easily, creating different effects, and providing greater economy as the entirety of the pencil is used. They are available in the same darkness range as wood-encased graphite pencils.

Liquid graphite pencils

These are pencils that write like pens. The technology was first invented in 1955 by Scripto and Parker Pens. Scripto’s liquid graphite formula came out about three months before Parker’s liquid lead formula. To avoid a lengthy patent fight the two companies agreed to share their formulas.

Charcoal pencils

Are made of charcoal and provide fuller blacks than graphite pencils, but tend to smudge easily and are more abrasive than graphite. Sepia-toned and white pencils are also available for duotone techniques.

Carbon pencils

They generally are made of a mixture of clay and lamp black, but are sometimes blended with charcoal or graphite depending on the darkness and manufacturer. They produce a fuller black than graphite pencils, but are smoother than charcoal.

Coloured pencils, or pencil crayons.

These have wax-like cores with pigment and other fillers. Multiple colours are often blended together.

Grease pencils

They write on virtually any surface (including glass, plastic, metal and photographs). The most commonly found grease pencils are encased in paper (Berol and Sanford Peel-off), but they can also be encased in wood (Staedtler Omnichrom).

Watercolour pencils

These are designed for use with watercolour techniques. The pencils can be used by themselves for sharp, bold lines. Strokes made by the pencil can also be saturated with water and spread with brushes.

Grading

Manufacturers distinguish their pencils by grading them, but there is no common standard. Two pencils of the same grade but different manufacturers will not necessarily make a mark of identical tone nor have the same hardness.

Most manufacturers, and almost all in Europe, designate their pencils with the letters H (commonly interpreted as “hardness”) to B (commonly “blackness”), as well as F (usually taken to mean “fineness”, although F pencils are no more fine or more easily sharpened than any other grade. Also known as “firm” in Japan).

As of 2009, a set of pencils ranging from a very hard, light-marking pencil to a very soft, black-marking pencil usually ranges from softest to hardest as follows:

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