An Eraser Primer: Choosing the best tool for undoing mistakes large and small

As you may know, I’m a devotee of pencils over pens for all manner of writing tasks, and we carry a selection of the finest (and my personal favourites) at the Bookshop.

But what is a pencil without an eraser? 

For many, the beauty of a pencil is the ability to erase one’s marks — so a pencil without an eraser is a bit like a day without sunshine; gets the job done, I suppose, but it’s so much less pleasurable.

Tim Hartford chose the pencil as one of his Next Fifty Things that Made the Modern Economy as one of the overlooked and often surprising inventions that changed the course of the world, but it is the eraser that makes the pencil special from its inky cousins. (The curious can read an excerpt from the entry on the pencil here.)

As pencil historian (yes, that’s a thing!) Henry Petroski said, “Ink is the cosmetic that ideas will wear when they go out in public. Graphite is their dirty truth.”

And the eraser is the humble invention at the thinker’s side as they polish their ideas for public consumption.

A brief history of the humble eraser

Erasers or rubbers have been around for centuries; wax tablets were used to remove charcoal marks from paper, rough stones were used to remove ink from papyrus, and in Japan and elsewhere, soft bread was used to rub out mistaken marks. 

But in 1770, an English engineer discovered that natural rubber would remove graphite pencil marks from paper quite effectively, and he developed and marketed the first eraser — which was dubbed a rubber in England and the colonies because of the material from which it was made (and, likely, the motion with which you use it!). 

Raw rubber, however, is perishable, and these early erasers were prone to fall apart and unreliable in all weathers. In 1839, Charles Goodyear (of the tire fame) discovered the process of vulcanisation to cure the rubber and make it more durable.

And in 1858 the first patent was awarded in the U.S. for attaching an eraser to the end of a pencil. (A nice try, but the patent was later invalidated for simply combining two existing products, rather than being an entirely new product.) 

Erasers in all shapes and types

Nowadays, erasers come in all shapes and sizes.  The most common include:

• Block or wedge erasers, which are essentially freestanding blocks

• Conical cap erasers designed to fit onto the ends of pencils - these are often designed to double as pencil caps, to protect your sharpened point in transit and stop graphite transferring to everything else in your bag or pencil case.

• Barrel or click erasers that look like a mechanical pencil, but with eraser material inside instead of graphite

• Novelty shaped erasers

• And attached pencil erasers.

While shape and size may be a matter of personal preference, the material from which the eraser is made is often the more important factor to consider.

Rubber erasers were originally made from natural rubber, but are now mostly made of SBR or synthetic rubber. The kind you find on the ends of your HB pencils frequently also include an abrasive, like pumice, and vegetable oil or other plasticisers. They’re quite firm so as to be able to attach them to the end of the pencil.

Artist’s gum erasers, sometimes just called art gum, are by contrast very soft and pliable. They’re typically made of vulcanised oils or synthetic rubber. They’re very good for erasing large areas without damaging the paper, but they crumble with use and leave quite a lot of eraser residue.  Their softness also makes them impractical for erasing precise, small areas.

Vinyl erasers came onto the scene in the mid-20th century. High quality vinyl erasers are said to erase cleaner than rubber erasers. They’re softer and less abrasive than typical rubber erasers as well. Engineers frequently prefer vinyl erasers because they are clean and precise.  Cheap, novelty erasers in bright colours and shapes are also made of hard vinyl, but frequently smear when actually used to erase. 

Kneaded erasers or putty erasers are common to the artists’ toolkit. They have a plastic, putty consistency and can be moulded into different shapes as needed, creating a fine point or a broad surface area. They lose efficacy over time because the graphite or charcoal particles are essentially absorbed into the mass of the eraser. 

Choosing an eraser

If you’re a pencil aficionado, you’ll have noticed by now that there is as much variety in the quality of the attached erasers as there is in the quality of the wood and graphite. Often you’ll find attractive or novelty pencils with rubbish graphite and/or erasers that smear rather than lift.

One of the many reasons I gravitate towards the Blackwing pencils is their ingenious, replaceable square erasers. As you use one up, simply loosen the ferrule clip (the metal bit that holds the eraser in) and extend or flip the eraser to give it new life. If you do a lot of erasing, you can even replace the erasers in their entirety with. And if you’re feeling particularly fancy, you can customise the colours to your liking.

Of course, you may prefer a dedicated block eraser for your needs — especially if your needs have the tendency to be large in scale. (I am, of course, referring to the scale of your drawing or project, not your mistakes.)

We carry a fine selection of Blackwing pencils and their associated erasers in the shop, along with other fine pencils (that have equally fine erasers). An art supply shop will be able to supply you with the more esoteric or specialised varieties.