Graphite pencils are the pencils we all know and love, and are most commonly used for drawing and completing schoolwork.
There are more varieties of graphite pencils than any other kind. In spite of the name, pencil leads do not contain the toxic chemical element lead, but are typically made with graphite and clay, or plastic polymers. This mixture leaves grey or black marks on the substrate, which can be erased easily.
Most graphite pencils have a combination of numbers or letters stamped onto it. These numbers and letters indicate how hard or soft the lead of a pencil is. The higher the number H, the harder the lead, meaning the pencil will produce a lighter line. The higher the number B, the softer the lead. This results in a darker line. The numbers and letters usually range from 6H to 9B.
The standard, familiar yellow pencils with pink erasers on top are HB, which sits right in the middle of the range.
A mechanical pencil – also known as a clutch pencil, a propelling pencil or technical pencil – is a pencil with a replaceable and mechanically extendable solid pigment core.
Unlike traditional wood-encased pencils, the graphite in a mechanical pencil is not bonded to the outer casing, but is instead extended as it becomes blunt.
Mechanical pencils provide lines of constant width without the need for repeated sharpening. They are used by people who work in pencil all day, such as draughtsmen, architects and mathematicians.
Mechanical pencils can also be used for fine-art drawing.
Did you know?
Mechanical pencils first appeared in the 18th century. Many designs were patented in the 19th and 20th centuries.
Mechanical pencils can be divided into two basic types: those that both hold the lead and can actively propel it forward, and those that only hold the lead in position.
Screw-based pencils were the most common type of mechanical pencil in the earlier part of the 1900s. This mechanism ensures that the lead is brought down the dispensing column by twisting a screw. A slider is moved down the barrel of the pencil.
Pencils of this type typically have a locking mechanism to allow the lead to be pushed back into the pencil.
Clutch pencils are activated by pressing the cap at the top. This opens jaws inside the tip, and the lead is able to drop down the barrel towards the tip of the pencil. When the cap is pushed down and the lead is in free-fall, it can fall out of the pencil entirely. It is worth holding the pencil just above the work surface, and the lead will stop when it touches the obstacle.
Some types of clutch pencils contain mechanisms to incrementally advance the lead.
Clutch pencils use thicker leads than screw-based pencils, and can only hold one piece of lead at a time.
Ratchet-based pencils have lead which is held in place by two or three small jaws inside a ring at the tip. A button on the end or side of the pencil controls the jaws. When the button is pushed, the jaws move forward and separate, which allows the lead to advance down the barrel of the pencil. When the button is released and the jaws retract, the “lead retainer” (a small rubber device inside the tip) keeps the lead in place, prevents the lead from either falling freely outward or riding back up into the barrel until the jaws recover their grip.
Ratchet-based pencils are a variant of the clutch pencil.
Mechanical pencils that are shaken back and forth to release lead are a type of ratchet-based pencil. Pencils of this type may also have a button so that the user can manually advance the lead if necessary.
Another type of ratchet-based pencil advances the lead automatically. In this design, the lead is advanced by a ratchet but only prevented from going back into the pencil by friction. The nib is a spring-loaded collar that, when depressed as the lead is worn away, extends out again when pressure is released.
Yet another type of ratchet-based pencil has a mechanism that twists the pencil lead at six degrees counter-clockwise every time the lead is pressed on to the paper. This means wear is evenly distributed and lines are of uniform thickness.
Most mechanical pencil mechanisms can only house a single lead diameter. Some pencils contain several mechanisms within the same housing, so as to offer a range of thicknesses, but these are rare.
The lead of mechanical pencils is also available in a range of hardness ratings. The hardness required will depend on the user’s desired balance between darkness and durability. The lead most commonly found in mechanical pencils is identical to HB, although not as thick.
Mechanical pencils with coloured leads do exist, but they are quite rare.
Different diameters of mechanical pencil lead and their uses
- 20 – technical work
- 30 – technical work
- 40 – technical work (only available in Japan)
- 50 – general writing, general technical work or beginner’s technical work
- 70 – general writing
- 90 – students/general writing
- 00 – rare, used in pre-1950 Parker pencils
- 18 – used in older pencils
- 00 – drafting lead-holders
- 15 – non-drafting lead-holders
- 60 – non-drafting lead-holders
Pop-a-point pencils, also known as stackable pencils or non-sharpening pencils , were pioneered by Taiwanese stationery manufacturer Bensia in the early 1970s
Many short pencil tips are housed in a cartridge-style plastic holder, decorated with patterns or colours. A blunt tip is removed by pulling it from the writing end of the plastic body and re-inserting it to the bottom of the holder.
A graphite stick is similar to a standard pencil, but instead of a wooden body with a lead core, they are comprised of solid sticks of graphite. The advantage of these graphite sticks is that they produce thicker, bolder lines that pencils can’t match.
Graphite sticks are used by artists to block in shadows and dark tones over a large surface area.
Charcoal pencils are very similar to graphite pencils but for the core made of compressed charcoal. This is a much softer material than graphite, producing richer and deeper blacks. Charcoal pencils combine the depth of charcoal with the control and precision that a pencil provides. These are usually used for impressionist drawings, quick sketches, or in conjunction with regular pencils to add a little more depth to a drawing.
A carpenter’s pencil is a pencil with flat sides. This makes it easier to hold and use in tight spaces that craftsmen are confronted with, such as the corners of pieces of wood. The fact that the core is not round means that thick or thin lines to be drawn by rotating the pencil. Thin lines are required for high precision markings and are easy to erase, while thick markings are needed to mark on rough surfaces such as wood or walls.
The type of lead used in these pencils is strong enough to withstand the stress of marking on these usual surfaces.
Typically carpenter’s pencils are more robust, and able to endure in dirty, demanding environments such as construction sites and warehouses.
Because of their unusual shape, carpenter’s pencils do not fit into a standard pencil sharpener. They are usually sharpened with a knife.
Similar pencils (called “jumbo pencils”) are sometimes used by children, although these tend to have a softer core. This allows the child to draw with less effort. Designers and artists may also use carpenter’s pencils to draw thick lines. They are sometimes used in calligraphy – Old English letters are easier to draw with a carpenter pencil than with an ordinary pen.
Did you know?
The flat pencil is one of the oldest types. The first versions were made by hollowing out sticks of juniper wood. A superior technique was then discovered: two wooden halves were carved with a groove running down them; a plumbago stick placed in one of the grooves; and the two halves then glued together – essentially the same method in use to this day.
Standard coloured pencils
These brightly coloured pencils are a staple of the classroom and craft box. The pencils are made of a wooden cylinder with a core of pigment. The pigment can be wax- or oil-based, and contain varying amounts of additives, pigments and binding agents. Professional-level pencil crayons are much softer, with wax-based pigments that transfer to paper more easily.
Pencil crayons come in a vast array of colours, but in the event that the right colour can’t be found it can be produced by layering pigments one on top of the other, and blending.
Erasable coloured pencils
Unlike wax-based coloured pencils, erasable pencil crayons can easily be erased.
Erasable pencil crayons are used mainly in sketching, where the objective is to create an outline using the same colour that other media (such as wax pencils, or watercolour paints) would fill or when the objective is to scan the colour sketch.
These pencils may be used by animators instead of the more traditional graphite pencils. They don’t smudge as easily, and the different colours allow for better separation of objects in the sketch.
Erasable colour pencils are also used in the publishing industry by copy-editors and proof-readers. Their markings stand out more than graphite but can be erased.
Water-soluble or watercolour pencils are pigment-based and work much in the same way as coloured pencils. The unique quality of watercolour pencils is that the “lead” pigment dissolves quickly in water. This means you can apply different amounts of water to the lines you have drawn to create a traditional watercolour effect, or dip the pencil directly in water to add very bold areas of colour.
Watercolour pencils are an ideal gateway into the watercolour world. They offer a greater degree of control when compared to a paintbrush.
They can also be used alongside coloured pencils to add splashes of very vibrant colour or highlights.