Tuesday 21 February 2017

Pencils and Erasers

This is another of my occasional posts whereby I look at what goes on when you actually make a drawing. In this case I shall ramble around a few ideas coming from that old and well-loved technique ‘pencil on paper’ and the indispensable eraser. 
I asked myself a very basic question about why marks stick on surfaces in an earlier post about ink on paper, so thought it a good idea to begin this post with the same question. In this case the sticking of graphite to paper. Perfect graphite consists of sheets of atom-thick carbon atoms whose intermolecular forces (specifically instantaneous induced dipoles) cause them to stick together, and the graphite in your pencil is made of many layers. However, the intermolecular forces between the graphite sheets and the paper are greater than the intermolecular forces between the graphite sheets, so when rubbed together, the graphite sticks to the page and shears off of your lead, leaving graphite on the page and a dull tip on your pencil.

The process is not due to a chemical reaction it is because of a physical process called physiosorption. Physiosorption creates a bond between two surfaces primarily through the effect of van der Waals forces, which are electrostatic as opposed to chemical. What's happening is that graphite (a naturally-occurring form of crystalline carbon) has a structure with lots of layers. These layers are only weakly bonded (if compared to a covalent or ionic bond) to each other by van der Waals forces, allowing them to shear easily away onto the paper when you use your pencil, which is why we use graphite in pencils in the first place. (Most solids won't rub off onto a surface so easily, see Mohs scale of mineral hardness, graphite is only between 1 and 2 on that scale). So after being sheared off the pencil tip, the graphite planes (referred to individually as graphene planes) will bond with the paper using the same van der Waals forces.  (It's the van der Waals attraction between surfaces and the foot-hairs of geckos that gives them the ability to climb up vertical walls) The process works so well that enough graphite is deposited in a line drawn by a pencil, that it can conduct electricity.  

Paper is also full of little holes, divots and fibers that get filled with graphite particles. Therefore another area that needs exploring when it comes to why marks adhere to the paper surface is the nature of paper itself, something that has again been touched on in earlier posts, but not yet on a microscopic level, I shall look at this at some point in the future.

Objects like pencils leave ‘skid marks’ on paper, the visible marks left by any solid which moves against another. Such marks are important evidence for any visual interpretation in relation to what happened when these contacts were made. For instance when car accidents are reconstructed, the size and shape of these marks can be used to determine vehicle speed and forces of acceleration or deceleration. They are a form of trace evidence. These types of marks are often encountered in criminal cases, so perhaps also think of bite marks or scratch marks. They represent a form of contact evidence produced in forensic terms according to Locard’s exchange principle. (Whereby the perpetrator of a crime will bring something into the crime scene and leave with something from it) or "Every contact leaves a trace".
I have looked at the idea of drawings as traces before, but in this case you can begin to think of a drawing as a form of ‘trace evidence’.
Trace evidence in police terms, is any type of material left at (or taken from) a crime scene, or the result of contact between two surfaces, such as shoes and a floor covering or soil, or fibers from where someone sat on an upholstered chair. So one way to read a drawing is for you to become more like Sherlock Holmes and to look at each physical mark and read it as indicative of a suspect action, as if the drawing was a crime scene.
 If I was to have to wipe out the evidence, the normal tool in the case of a pencil drawing would be a rubber or eraser. If it was a crime scene of course the first question would be why have certain things been removed from the scene? But in this case I’m looking more at how.

An eraser works in several ways, one of which is by giving the graphite that has adhered to the paper something more attractive to stick to. The structure of the rubber material makes the graphite stick more strongly to it than to the paper. Because it has a stronger attraction to the graphite than the paper, the stronger bond will remove the graphite from the paper when you move the eraser.
However, simply washing with soap and water will also remove graphite from paper. Water and soap will interrupt the van der Waals bonding between the graphite planes. Again this could reflect the idea of clearing up a crime scene. So would you decide to wash marks out of a drawing rather than rub them out? How would this effect the final outcome?
Thinking of washing, we always used to keep a pumice stone in the bathroom which was used to get rid of hard to remove grime and pumice is also an important ingredient in erasers. Pumice, in the form of a particular volcanic ash from Italy was used mixed in with rubber to give erasers their abrasive quality, whereby they break down the surface of the paper in order to detach the graphite marks. Hence Faber's the Pink Pearl.
19th century pencil drawing of Pompeii

Pompeii was lost under volcanic ash and as the ruins were uncovered they became a favourite place for travellers to visit and make drawings. There are thousands of 'tourists' drawings of these ruins and they became an integral part of the European Romantic tradition. Artists would follow 'the Grand Tour' and following on from the artists who made these sites visible, the elite of Northern Europe travelled to centres like Pompeii as necessary rites of passage. These romantic ruins invited spectators' reflections on transience, death, and decay. The romance of the ruin eventually became a key concept that lay at the core of certain artistic practices. Rauschenberg famously erased a De Kooning drawing, in effect erasing the idea of the genius artist, another romantic trope. 

Rauschenberg: erased De Kooning

Vija Celmins: Eraser, 1967 acrylic on balsa wood 6-5/8 x 20 x 3-1/8 inches

In 1966-67, Vija Celmins made four painted sculptures: three Pink Pearl erasers and one pencil, meticulously crafted of painted balsa wood and giganticised. The edges of the erasers are slightly worn, they have been used; but for what purpose? The construction of exact replicas used to be part of another set of art tropes, including 'realism' and in the 1960s objects taken from the everyday and remade larger were seen as part of the 'Pop Art' genre. I would however like to propose a conceptual piece, I construct a hypothetical drawing, whereby the Pink Pearl is used to erase a 'Grand tour' pencil drawing of the ruins of Pompeii. A final gesture to signal the end of Romanticism.

Edward Naime, an English engineer, is credited with the invention of the eraser (1770). Up until that time, people usually used rolled-up pieces of white bread to erase pencil marks, and bread as a staple food is suggestive of a completely different narrative. As you can see I’m just following thoughts as they occur to me. Hopefully making the idea of undertaking some research interesting, and perhaps helping to confront that old art/science divide that so many of us worry about. I also thought it fascinating that when in 1858, Hymen Lipman received a patent for attaching erasers to the ends of pencils, it was invalidated because it combined two existing products rather than an invented new one.

Coda:

A while after putting up this post I came across the work of Lucienne Rickard. She had a project based at the Tasmanian Museum and Art Gallery, whereby she spent weeks drawing large images of critically endangered species in graphite. She would draw lost species as well, deer and crayfish, mice and turtles, a lake newt and a robber frog and when she had finished each drawing she would rub it out. The last drawing to be done was of a critically endangered swift parrot and a crowd came on the final day to watch it being erased. Each drawing had been done on the same sheet of paper and as she had erased these drawings, shards of 25 rubbers, the shavings from many sharpened pencils and removed graphite particles were collecting on the floor below it. Ghosts of all the drawings could be seen as you looked carefully at the paper, remains of lost drawings caught in the fibres of the paper and haunting the final image of the parrot, as it too was erased. In all she had drawn 38 images of disappearing or disappeared flora and fauna, each one reduced to a ghost of its former self by the process of erasure. 


Lucienne Rickard: extinction studies 

In Rickard's work we can see the act of erasure being used as a powerful metaphor, she takes Rauschenberg's idea of erasing the work of another artist and uses it to raise awareness of our collective responsibility to the environment. 
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