Hardness of Pencils – Guide to the Graphite Grading Scale

Drawing is one of the most accessible forms of art; all you need is a pencil and paper. However, if you wish to progress, you need to understand what pencil lead hardness is. Each of the pencil lead types offer a way to help you produce different drawing techniques. In this article, you can read further to find out more about the hardness of pencils.

Definition of Pencil Hardness

What pencil is best for sketching? You might be asking yourself this question if you have ever been to a stationary store, and you are standing in front of a wall of different pencil choices. A basic definition would be that the lead or core of a pencil is made from graphite that has been ground and a clay filler.

This pencil lead can be categorized in what is known as a lead hardness scale. This means pencils come in different degrees of softness or hardness.

These different pencil lead types help artists to choose the proper pencil for their artistic needs, which means the pencil provides a certain mark or line they are looking for.

Importance of Pencil Hardness in Writing and Drawing

The hardness of pencils determines how the lines or marks are going to appear on the paper surface. When used, softer pencils will produce broad lines that are thicker and are best used by artists for drawing purposes.

When writing, you do not want a pencil that is too dark or too light. A medium pencil, or what we know as an HB pencil is ideal for writing purposes.

These types of pencils can easily be erased if you make a mistake. For drawing purposes, you could use a range of pencil lead types to achieve the look you are going for.

Brief History of Pencil Making

When we know a pencil is made from graphite, why is it called a pencil lead? Ancient Egyptians discovered how to pour molten lead into hollowed-out reeds or bamboo and used the final product to write with, and in the Middle Ages, lumps of lead were used for drawing.

However, even though they did not know at the time, lead is hazardous to health, and is too solid to perform the task of writing well.

Many years later, graphite was discovered and found to be much softer than lead. However, in those times, using graphite darkened the hands and was a bit messier to use today. The graphite was then wrapped in string.

During the 18^th century, a scientist by the name of Nicholas-Jacques Conte, who served in Napoleon Bonaparte’s army, invented the modern-day wooden encased lead pencil. Today, we have also developed a range of pencil lead types.

Understanding Pencil Hardness

To understand the hardness of pencils, there is a pencil lead hardness scale. The most common lead hardness scale is the European system, which uses letters and numbers to identify each pencil grade.  We will be dealing further with this later in the article, as this is more of a comprehensive system.

There is also an American system, where you will find the most common pencil everyone should be familiar with, the #2 pencil. This is equivalent to the HB pencil by European standards. So, when you purchase a pencil, you might notice that there is a “no.2” or “HB” marking next to each other. The number 4 would be the hardest pencil.

However, there is no set international standard for grading the hardness of pencils. When using Japanese pencils, they might appear to be darker than those equivalent to European pencils, even though the same system is used in both cases. So, the grade of pencil lead hardness can differ from brand to brand.

Pencil Lead Hardness Scale Explained

As we mentioned, we are going to stick to the more comprehensive European system of grading pencils. The drawing pencil scale consists of 20 different degrees of hardness, each one containing a number and letter.

The scale ranges from 9H to 9B, which is from the hardest to softest or blackness of a pencil. The designated letters come from hardness and blackness.

In the middle, you have the HB (Hard Black) and F (Firm) pencils, which have medium pencil hardness. Pencils designated with a B-grade are softer and contain a larger percentage of graphite, which also makes them darker, so you do not have to press hard. The H-grade pencils are harder and contain more clay and less graphite, which produces lighter marks or lines, so you have to press harder to get darker lines.

You can also get pencils that go up to 12B, which is a very dark pencil and could be considered darker than charcoal pencils. Charcoal is generally much flakier and darker than graphite, and can be easily smudged, unlike graphite.

Differences Between Soft, Medium, and Hard Pencils

The major difference between all three soft, medium, and hard pencils is the amount of graphite and clay present. The harder the pencil, the more clay is present in the pencil, which produces a lighter and thinner mark. Medium pencils have more of a balanced composition and are the type of pencil most moms would pick for their children to use at school.

Soft pencils contain more graphite than clay, which produces a darker and smoother writing experience, and softer handling.

The Science Behind Pencil Hardness

You most probably have a general idea by now of the different pencil lead types available and what pencils are made from. However, we can look closer at the composition of a graphite pencil to gain a bit more understanding.

Graphite and Clay Composition

Graphite and clay play a big role in determining pencil hardness. As we have learned, it is the composition and ratio of graphite versus clay that make up the different types of pencils. Pencil makers use different ratios of graphite and clay to produce hard and soft pencil leads.

The hard pencils have more clay, which then has about 20 percent graphite, while softer pencils contain around 90 percent graphite and less clay.

The composition of a pencil lead usually includes graphite, clay, and a binder, such as resins, wax, or a polymer.

The lead is then also then surrounded by a wood casing. Pencil casings come in various designs based on where and how the pencil will be used.

When the pencil lead is being processed, the graphite is first ground to a powder and then mixed with water. This paste is then fired in a kiln to produce the lead we use to write with. The duration as well as the heat also plays a part in the hardness of a pencil.

The Advantages and Disadvantages of Different Pencil Hardness

Not all pencils can be used for every purpose. However, many professionals and artists use a range of pencils and do not stick to a single grade of pencil. So, what are some of the pros and cons of each pencil lead hardness choice?

Soft Pencils

Let us start with soft pencils, which we know have more graphite and less clay. When looking at the drawing pencil scale, soft pencils are categorized from B to 9B. Let us now have a look at a few pros and cons.

Medium Pencils

This is the most common type of pencil that most of us use every day, and these pencils are perfect to take to school. As with both soft and hard pencils, medium-grade pencils also have a few advantages and disadvantages.

Hard Pencils

Hard pencils as we know have more clay and less graphite, and therefore, provide different effects than other grades of pencils. Let us see what advantages and disadvantages these pencils have to offer.