The Informed Illustrator: Eraser Facts and Fiction

Now, being an illustrator that works digitally, I mainly use the delete key, but when I’m drawing from the figure, or preparing a sketch for a client on a real piece of paper, I use an eraser to do my editing. There are several types of erasers in a variety of shapes and sizes, and each has a different purpose. There are a number of websites that present comprehensive information about the history of erasers, their material make up, and how they are made. This article will be about everything else.

Eraser Credulity

It should be obvious that erasers were made to remove marks from surfaces. Erasers are standard equipment in every artist’s, and draftsperson’s arsenal of drawing implements. Artists need them, especially those who tend to be a bit free spirited when it comes to drawing the figure. And then there are the rest of us, who can never get things right the first time. It is always desirable to have a tool to eradicate marks that don’t belong where they somehow happened to appear.

Pencils are the most common items erasers are used for, so this discussion will focus mainly on methods and materials using pencils. Although it’s my understanding that an eraser can be used to level a wobbly drawing table. In fact, I’ve seen whole classrooms full of useless drawing tables become fully functional by way of a box of erasers. Now, you may think I’m getting sidetracked by my mentioning it, but if you ever tried to produce a drawing on a piece of paper that was taped to a wobbly table, then you know that sacrificing one eraser to steady the table will result in a lot less mistakes that would probably require several erasures to fix.

Eraser Physics

Erasers pick up graphite particles thus removing them from a surface such as paper. There are erasers that do this because they are made of a tacky material, like a kneaded eraser, and there are erasers that do it by attracting the particles through fiction, like a pink pearl or plastic eraser. The friction produces a molecular attraction and adhesion. Smoother surfaces produce less resistance, resulting in less friction, while rougher surfaces result in more resistance creating more friction.

Each of the several different types of erasers corresponds to the properties of the surfaces they are applied to. So when using an eraser it is very important to pay attention to the surface property of the paper being used. For best results select a rougher surface eraser for a rougher paper such as a cold press surface, or laid paper. Select a smoother surface eraser for a smoother paper such as a hot press, or vellum surface.

Another lesser consideration, but none-the-less an important one, is the type of pencil or graphite used. This can sometimes have a bearing on which eraser will work best. A Dixon Raven has more graphite content than a Prismacolor Ebony, which has more carbon blended into it, so the choice of eraser may also vary.

The Goldilocks Theory

Recalled from the story of Goldilocks and the Three Bears, when an eraser is too rough it usually damages the surface of the paper by removing any coating that might exist and dislodging the paper fibers. This alters the way the paper surface accepts new pencil marks, which in turn, causes the erased section of a drawing to have a different appearance than its surrounding areas.

When an eraser is too soft, or too smooth, the paper surface remains intact, but the graphite becomes smeared and lightened rather than removed. More pressure or friction may still leave a ghost mark on the surface. And, in the case of art gum erasers and some plastic erasers that are made of a soft material, the eraser actually breaks down, or crumbles before any damage occurs to the paper surface, but also before any marks are completely removed.

When the abrasive roughness or smoothness of the eraser matches the surface of the paper, pencil marks can be removed easily without an excess of rubbing or the application of extraordinary pressure. The match of eraser to paper is just right.

Eraser Exposé

Art Gum

I have a vivid memory of myself, and three or four of my friends sitting around one day chewing on art gum erasers after our stash of Halloween candy had run out. I recall they were crumblier than Rice Krispies eaten dry. Most of us were familiar with that consistency, because back in the day, art gum erasers were also called soap erasers, and mothers galore would stick them in the mouths of their profanity-uttering children. And speaking of profanity uttering children, industrious pre-teens carve them into heart or skull shapes so they can stamp out the symbols of admiration they send to their fellow pre-teens.

Eraser Bag

The last time I checked there were only three people on earth that knew how to properly use an eraser bag, and no two of them live in the same hemisphere. One day an eraser manufacturer was wondering what to do with all the excess flakes and powder that was created when real erasers are cut down to their actual shape. Then eureka! Stuff them into a cloth bag and sell them to baseball pitchers so they can mop the sweat off their brows. After all, the bags certainly couldn’t be used to erase anything.

Kneaded Eraser

Kneaded erasers are great for sculpting small figures and animals. A lot of dimensional illustrators use Glow in the Dark Sculpey® to fashion figures, but why waste money. As long as you don’t mind that greenish gray, goose poop color, you’re good to go. And they never dry out. So, if you don’t like cute animals, you can smack them down and turn them into candy shapes for playing tricks on your friends and loved ones.

Plastic Eraser

Back in the 60’s eraser manufacturers paused in their rubber eraser making frenzy, and took a look around them. They saw that silverware, dishes, lamps, garden tools, dog’s houses, children’s playgrounds, and even automobiles were being made out of plastic. And all were selling like hot cakes. It was time to get on the bandwagon. The first attempts to make plastic erasers resulted in little brittle blocks that didn’t erase anything. This result was later dubbed “the conspicuous Lego block mistake”. Soon the inventors realized they needed to find a substance to soften the plastic, and after chicken soup didn’t work they were stumped for a while. Next they tried formaldehyde, but this meant that plastic erasers were off the menu for starving artists. Then they tried non-toxic antifreeze, which worked wonderfully and allowed artists to store their plastic erasers in the freezer next to their popsicles.

Vinyl Eraser

An eraser manufacturer in Germany found several cases of a white material that had been buried during the First World War. And, even though they were clearly marked polyvinyl chloride, the inventors tried to make a batch of erasers out of them. The material worked quite well, but for only one thing -- drinking straws. Naturally artists found this less than acceptable for erasing, but quite useful for blowing pastel dust off of drawings. Well one day, a plumber had a brilliant idea while he was sipping on his milkshake. He could profit more if he replaced copper tubing with the straws. The rest is history. The PVC pipe was born. Well now. Where did this leave our poor eraser manufacturers? Gradually, they were finally able to make the material pliable again by adding, of all things, sardines and kippers. And, by keeping chloride in the mix they, once again, had not only created an edible eraser, but one that promoted healthy kidney function.

Pink Pearl Eraser

The eraser of choice for adolescents, the Pink Pearl, in addition to removing fingerprints from gin bottles, has many innovative uses. Teachers beware; the answers to whole social studies tests have been scripted on the backs of pink pearl erasers. I’ve seen it! And, easily thrown and caught inside the classroom, the pink pearl is the preferred method of texting. Reptile owners will enjoy the fact that a pink pearl can be used to safely prop open the mouth of a rattlesnake so the venom can be extracted. And with a bit of whittling, pink pearls make great toe separators for those who enjoy a fashionable pedicure. Lastly, men and women the world over know, that a brisk rubbing with a pink pearl will remove unwanted body hair.

But Seriously

For illustrators, erasers are not only eradicators, but are valuable tools that can be used subtly or boldly to enhance the tonality in a drawing.

Kneaded Eraser

The kneaded eraser is primarily a tonal alteration tool. It is very effective at lightening an area of a drawing, and it can do this without any rubbing. And as erasers go it stands alone with this distinction. It’s putty like consistency allows it to be shaped for special situations. It can be formed into a point for delicate applications, or flattened to lighten a broad area, as need be. When it gets dirty it can be “kneaded” back into a clean state.

Special note: Other putty products I’ve seen used in place of a kneaded eraser, e.g., Sticky-Tack or Blu-Tack putty, although seemingly the same material, are more pliable and tacky. And, they will leave an oily stain on the paper surface.

Art Gum Eraser

It is easy to use up an entire art gum eraser on one drawing if it is the only eraser used. Art Gum erasers aren’t meant to last. They are designed not to harm the surface of paper, and they do this by crumbling apart. In fact you can split them with your fingernail. Therefore they are only light duty erasers.

Special note: Art gum erasers leave deposits on the surface of a drawing. So removing the residue from the surface should be done with care. I’ve seen drawings smudged by brushing the surface with the back of a hand to clear off art gum shavings.

Plastic Eraser

Plastic erasers have a very smooth surface and are relatively non-abrasive. They work best removing graphite from smooth surface papers. They tend to smudge pencil marks on rough surfaces and even drive the graphite into the paper fibers.

Special note: Often confused with vinyl erasers, plastic erasers are harder and less flexible. Also, plastic erasers harden and become more brittle over time, even more so than rubber erasers. The ones that contain colored dye can transfer some of the dye onto the paper surface if overused.

Vinyl Eraser

A very good all purpose eraser, vinyl erasers are slightly rougher than plastic erasers and much more flexible. Because they generate a fair share of friction they can remove pencil marks completely, or smudge them for effects if need be.

Special note: The surface of vinyl erasers tends to get quite dirty, and can actually put smudge marks onto the paper surface instead of removing them. It is sometimes necessary to using a spare vinyl eraser to clean the one being used.

Pink Pearl Eraser

Pink Pearl erasers fall into the class of rubber erasers, and are made out of natural or synthetic rubber. They are more abrasive than the other forms of erasers and are best used where aggressive erasing is needed. They work far better on rough surfaces than smooth ones. Ebony pencil, a laid surface paper, and a pink pearl make an excellent drawing combination.

Special note: Pink Pearls suffer from all of the other detriments mentioned above. They get dirty, leave reside, and dry out, and when dried out they can deposit dye.

Eraser Bag

An eraser bag or cleaning pad is a porous cloth bag filled with powdered eraser material. The eraser powder when deposited on paper and gently rubbed can remove light smudges and handprints from graphite drawings.

Special note: The eraser bag should be gently squeezed and shaken above the surface of the paper to deposit the powder on the surface. A soft cleanable cloth can then be used to wipe the smudges off. It is best not to use the bag itself. When the bag is used it gets dirty, and once it is dirty it cannot be cleaned or washed.

Non-Art Eraser

Magic Eraser

Not to be used as a drawing tool, the Mr. Clean® Magic Eraser is none-the-less a very useful tool for artists. It will remove graphite from the surfaces of objects that artists use in conjunction with their drawings, e.g., pencil cases, pencil handles, dirty erasers, drafting tables, etc. It’s very useful when managing the residual graphite that can contaminate a drawing.

Special note: The Magic Eraser uses a mild chemical abrasive to clean surfaces. The chemical can cause skin irritation for some people, and it can damage the surface of some materials, especially if it is used too aggressively. Although it doesn’t seem so, the Magic Eraser is actually a sanding sponge.

Tuesday, November 13, 2012

Eraser Facts and Fiction