Saturday, 21 April 2012

Elephant No. 202: Fingerprints

It's the weekend and I wanted to do something relatively mindless, so I thought I'd try making an elephant using nothing but fingerprints. I've actually never tried producing something with multiple fingerprints, so this could be interesting.

A fingerprint is the impression left by the ridges in a finger—normally human, but also possible in some other species. Fingerprints are normally created by the natural secretions from sweat glands in the hand. They can also result from impressions left in soft materials such as clay, and can be produced by artificial means such as ink.

The art of fingerprint identification is known as dactyloscopy (literally "hand print identification"), and involves a comparison of the impressions of finger ridges. No two impressions are ever identical, even when made by the same individual, due to subtle alterations in hand pressure each time. As a result, modern fingerprint identification requires experts and highly sophisticated tools.

Typical fingerprint impression.

There three primary types of prints used for identification at a crime scene. Chief among these is a "latent print", which is the chance impression of finger ridges on an object. "Latent prints" are invisible to the naked eye, and usually require powder, chemical methods or special light sources in order to be revealed. "Patent prints" are those that can be seen without help, such as impressions made with ink, paint, dirt or even blood. "Plastic prints" are those that leave a visible impression in materials such as window putty, mud, clay or even thick grease or paint.

Fingerprints were used as signatures on clay tablets as far back as the second millennium B.C. in Babylon, and by 246 B.C., Chinese officials were pressing their fingerprints into clay document seals. With the advent of silk and paper in China, handprints were added to the paper itself. As early as A.D. 300, fingerprints and handprints appear to have served as a form of legal proof across Asia—likely more in terms of finger and hand size and obvious scars, rather than the minute detail required as legal proof today.

In 1684, English physician Nehemiah Grew published the first scientific paper describing the ridge structure of the skin on fingers and palms. A year later, anatomy books published by Dutch physician Govard Bidloo and Italian physician Marcello Malpighi featured illustrations showing a recognizable ridge structure on fingers. By 1788, German anatomist John Christoph Andreas Mayer had recognized that fingerprints are unique to each person.

In 1823, Czech anatomy professor Jan Evangelista Purkinje was the first to discuss individual fingerprint patters, although he did not mention using these to identify people. In 1853, German anatomist Georg von Meissner  studied the ridges in fingers, but also took it no further. 

Five years later, however, the first formal fingerprinting was initiated in India. By 1877, Sir William James Herschel had established the use of fingerprints on contracts and deeds as extra proof of legality, and he registered the fingerprints of government pensioners to ensure that relatives did not continue to collect money after the pensioner's death. He also fingerprinted prisoners upon sentencing.

Early fingerprint and handprint exemplar taken by William Herschel, 1859–1860.

In 1880, the Scottish surgeon Dr. Henry Faulds, then working in a Tokyo hospital, published his first paper on fingerprinting, established the first true fingerprint classification, and managed to identify fingerprints left on a vial. When he returned to England in 1886, he offered his research to London's Metropolitan Police, but his work was ignored. 

Although other people continued to work on fingerprinting as a means of identification, it wasn't until 1892 that the world's first fingerprint bureau was established. Established in Argentina by Buenos Aires chief of police, Juan Vucetich, fingerprinting was used to solve a murder that same year by an Inspector Alvarez, who was a colleague of Vucetich. 

By 1897, a fingerprint bureau had also been established in Calcutta, India. Azizul Haque and Hem Chandra Bose, who worked for the bureau, are credited with the development of a fingerprint system ultimately named after their supervisor, Sir Edward Richard Henry, who also made several improvements. The Henry Classification System has since become the standard fingerprint classification in most English-speaking countries. The two other popular classification systems are the Roscher system, which was developed in Germany and is used in Germany and Japan; and the Vucetich system, which is used throughout South America.

These systems classify fingerprints based on patterns such as arch, loop and whorl, along with more complex sub-patterns such as "tented arch", "radial loop" and "accidental whorl". There are even exotic names for some patterns such as "peacock's eye". 

There are a few peculiarities in fingerprints as well. Children's latent prints, for example, disappear much more quickly than those of adults. This is attributed to a lack of the types of waxy oils that become present after puberty. Fingerprints can also be used to detect drugs and other compounds contained in skin secretions, such as tobacco, coffee and cannabis. 

Some people actually have no fingerprints. The rare medical conditions adermatoglyphia, and ectodermal dysplasia, result in completely smooth fingertips. Even stranger, the anti-cancer medication capecitabine can cause the loss of fingerprints. Some people have their fingerprints permanently erased, either through plastic surgery, burning, or acid, although these extreme methods are primarily used by criminals to reduce their chances of conviction. The gangster John Dillinger famously tried—and failed—to burn off his fingerprints with acid.

A few other animals, such as primates, have unique fingerprints as well. Interestingly, one study has found that the fingerprints of a human and a koala are virtually indistinguishable under an electron microscope.

For today's elephant, I decided to pour a bunch of paints onto a palette and simply play at making an elephant using nothing but fingerprints. I used a pad of inexpensive sketchpad paper and acrylic paint for this little exercise.

I used the three primary colours—blue, yellow and red—and the three secondary colours—green, orange and purple—pouring a small amount of paint into the different compartments of my palette. To make the fingerprints, I simply dipped a finger in the paint, patted it a bit in the central well of my palette, and stamped it into the paper.

The method was very simple. I wet my finger with paint, removed any globby excess before I hit the paper, then stamped fingerprints wherever they looked good to me. I didn't pay much attention to getting perfect fingerprints, as you will see below. A few things I noticed as I went along:

1. The first couple of finger impressions will be roundish, but as you continue, the paint on the outside edges of your finger will form interesting lines. I used my fingers more or less as rubber stamps, rather than smearing as I would if I were fingerpainting.

2. Layering is key, and will allow you to produce all kinds of interesting effects. Colour also helps in this, as the use of complementary colours—red with green, blue with orange, yellow with purple—causes a sort of optical vibration, which makes the colours pop a bit more.

3. Leaving some white space also helps with the modelling, although I also liked the areas where I pretty much saturated things with paint.

4. I didn't bother to wipe my fingers between colours, as the acrylic dried so fast that it hardly mattered. I also liked the effect I got when colours were slightly blended.

5. The easiest fingers to use are the index finger (obviously), the middle finger, and the baby finger. I didn't use my thumb even once for any of these, and I only used my ring finger when I wanted an unsullied colour like bright yellow.

I made four of these, but rather than describe each one, I'll simply show the various stages for each—at least those that I remembered to photograph. There are also a few detail shots in here to give you an idea of what the fingerprints looked like at various stages.

I apologize in advance for the changing colour of the paper. It's a very weird colour to photograph, as it has both green and pink undertones. I concentrated on making the paint colours more or less true to what they look like in real life, but sometimes that made the paper colour go wonky.

Elephant One


Elephant Two

Elephant Three

Elephant Four



This was a very easy activity, and only took about an hour for all four paintings. My original thought had been to make precise thumbprints, then draw around them, but this was much more fun—and it's definitely something I'm adding to my repertoire.

Elephant Lore of the Day 
Although elephants aren't fingerprinted, there are many ways to identify specific individuals. An elephant's ears are the most common means of identification, as each ear is highly unique. Not only is the structure of veins and ridges different for each elephant, but all elephants generally bear specific scars and tears in their ears.

Elephant footprints are also highly unique. Although they don't have the whorls and ridges that we do, they do have specific ridges, cracks and fissures that people can use to track an individual elephant. 

Many people also identify elephants by their tusks, which are also quite unique from elephant to elephant. Some elephants have tusks of different lengths, tusks that may have been broken or cracked, tusks that are overly curled or turned in, and so forth.

Identification of elephants by the above three means is photographic, rather than by direct inky contact. In addition, as a way of tracking individual elephants and stepping up the fight against poaching, some countries are beginning to apply DNA fingerprinting to both captive and wild elephants. This is often done, oddly enough, using elephant dung as the sample. DNA fingerprinting of elephants not only identifies the elephant itself, but also its tusks—which may one day lead to an ability to track down and prosecute those involved in the illicit ivory trade.

Back of an African elephant's ear, Kruger National Park, South Africa, 2008.
This elephant would be easy to identify by its ear, as it has many distinctive injuries.
Photo: Terry Richard


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