DELETE, DELETE, DELETE

Correction fluid was a mainstay of students and secretaries the world over. The exact composition of the fluid differs between manufacturers and countries of production. The general composition comprised of a combination of an opacifying agent and a solvent. The solvents are organic solvents, so over time they dissipate or evaporate and this caused the liquid to thicken.

The manufacturers recognised this and sold bottles of thinner so that customers could add a few drops to ensure that the correction fluid would again become liquid and less clumpy. Some manufacturers also added an unpleasant fragrance to discourage inhalant abuse.

Correction fluid is made of an opacifying agent, a polymeric film former, solvent and other miscellaneous ingredient. The opacifying agent is key as this is what is responsible for covering up the mistake. The most utilised opacifying agent is titanium dioxide. It doesn’t absorb light and produces a predominantly white colour. Mixing the titanium dioxide with different materials creates different colours, which is responsible for different coloured correction fluids.

While the opacifying agent covers the error, a polymeric material is used to create a film and affix it to paper. The film is designed to be strong so it will stay in place, and not crack, flake or otherwise dislodge. A variety of polymeric resins can be used such as acrylic resins, petroleum resins and synthetic rubber. A solvent is necessary to control the viscosity and dry time of the correction fluid so it can be applied evenly and smoothly, but dry in a reasonable time.

The solvent dilutes the formula and then evaporates to leave a dried film. It is also responsible for improving stability and making the ingredients more compatible. The solvent must evaporate quickly so it can be written over, but it cannot evaporate too fast or the polymer may solidify in the bottle or on application.

Solvents can be aqueous-based or organic-based. Aqueous-based solvents are used for correction fluids that will cover oil-based inks, and are usually a mixture of water and alcohol. Organicbased solvents include acetone and are better suited to covering water-based inks. There are other ingredients added to the correction fluid formula to optimise stability and performance.

The original correction fluid was invented by an American, Bette Nesmith Graham, who was the founder of Liquid Paper. She worked as a secretary at a bank – a job she needed to do to support her son after her divorce. She was, however, not the most proficient typist.

However, as an artist she knew that artists could not erase errors, so they simply paint over the error, and it make her mimic this form of correction in her work. Bette took a small bottle with white tempera and a watercolour brush to work, which she used to correct mistakes for five years before she started her own company.

She initially ran the business from her home but in 1979 she sold the company Liquid Paper to Gillette Corporation for $47.5-million.

Correction tape was the evolution of correction fluid, with the added bonus of being dry immediately. There is time delay and no drips, splashes, clumps or bumps. Some brands are easier to apply and smooths out with little pressure while other need more skill to apply. The upside is that there is no odour and no risk of being abused as an inhalant.

There are many different brands globally, so preference and market share differ geographically. In South Africa, Tipp-ex and Pentel were the most common brands early on but there are literally dozens to choose from now.

Erasers are easy to use and can remove pencil, which is in itself not the most permanent of mediums. In years gone by, people used bees wax, bread and even rough stones to erase lead or charcoal pencil marks.

When Edward Nairne accidentally picked up a piece of rubber instead of bread and erased an error, he discovered the properties of rubber and from then on sold rubbers (as they came to be known). The price of three shillings per half inch cube was quite high given that this was in 1770.

The evolution came with the advent of vulcanisation, discovered by Charles Goodyear, meaning that the rubber would not perish quite so quickly. This contributed to erasers becoming a common item.

Different erasers for different purposes are available these days and not all of them are made from rubber. Some are made from such esoteric material such as fibreglass or vinyl. Rubber erasers, like the ones used by scholars, are moderately hard and come in a range of colours, sizes and shapes.

These are generally used to remove graphite from paper and shed a bit of

themselves in the process, leaving little rubber crumbs that need to be brushed off the page.

The next type would be the gum eraser, or art gum eraser. Being softer than the conventional rubber eraser and also shedding a lot when used, the crumbs will be very evident. Gum erasers are suitable for more paper types because of their soft, gummy texture.

Even softer than the gum eraser is the kneaded eraser, used by pencil artists especially. This is pliable and can be moulded and shaped into a fine point, making it good for precise erasing. The best technique is to press, twist and pull away rather than actively rubbing the paper.

The pencil eraser, or erasil, is shaped like a pencil and it can even be sharpened into a point. It has a vinyl tip which is quite hard so it can be used with precision. The firmness of the tip means that it is not suitable for all types of paper as it could cause damage to the paper. Kids used to – and still do – like to collect anything and everything. So, when smelly rubbers hit the school scene in the 80s, they became a coveted collectible. Not only did your mum not mind buying them for you –well, rubbers were an essential pencil case item – but they had the novelty factor, too! Each rubber was shaped like something, from a Swiss roll cake to a bunch of grapes and a can of coke –with a smell to match. Do you remember bubblegum rubbers? Mmmm!

These erasers are hard and are favoured by draughtsmen for their clean and complete erasing. Vinyl erasers are even capable of removing ink, however, because of their texture you need to be cautious in your application and again, it may damage some types of paper.

Poster putty can also be used as an eraser – although not it’s intended use, but if pressed to graphite, charcoal or pastel, it will adhere to the substance and when pulled away, will remove the pigment. The method needs to be applied several times for complete removal. Once adulterated with pigment and the oils from the artists hands and mediums, it becomes useless and needs to be discarded.

Fibreglass erasers can remove graphite, ink and even clean circuit boards. These erasers are usually shaped like a pen and are very hard and abrasive. Care needs to be taken that they are not inhaled or accidentally come into contact with your eyes as the fibres shed and break down during use.

With so many types and compositions of erasers, from fun novelty erasers to high end and artists’ fare, you can’t err by choosing an eraser. �