From a young age, children learn that art and science are separate realms of thought that are governed by different sides of the brain: left-brained thinkers tend to reason through analysis, while right-brained thinkers demonstrate more creativity. Although the neuroscience behind this division is compelling, it does not prove that the two sides are mutually exclusive. In fact, the colorful art on city walls, colloquially referred to as street art or graffiti, is a prime example of the overlap between scientific principles and artistic expression.
Street art is painted using an aerosol can, which works for one simple reason: it is constantly under pressure. Its external environment encourages the compact air and paint particles within the can to take a “breath” of fresh air and diffuse into the real world. Yet, the paint in a can cannot escape to a lower pressure unless a finger exerts force on the cap and releases some of the tension into a form of art.
Caps are major tools for skilled painters. Graffiti artists often begin drafting a work by painting large outlines. The type of cap used allows artists to work more efficiently by spraying the desired shape and amount of paint. Each cap has a distinct thickness and personality that modifies the paint emission from the can. The two broad types are fat and skinny, but there are a variety of other specific designs, including calligraphy, needle, and astro-fat caps, that are used for a range of artistic purposes. As the name suggests, fat caps produce the densest lines—typically four to five inches wide—by spitting out the highest volume of paint with the greatest radius. Their structure has a slightly larger opening at the nozzle than other caps. Fat caps get any job done quickly and take care of the busy work of “fills,” a term for coloring in a sketch with spray paint before outlining the letters again in a different color. By contrast, skinny caps are for the details. “Skinnies” produce lines that are roughly an inch in width, which make them suitable for sharpening the rough draft laid out by fat caps and decorating with ornamentation. When it comes down to the details, the engineered design of each cap matters.
In graffiti, the paint defines a piece’s character. Spray paint is a medium that allows artists to paint over and over without a trace of the original work left behind. It is easy to take this feature for granted, but the concept of opacity makes it possible. From a scientific perspective, opacity measures how difficult it is for light to pass through the substance; the denser the paint is, the more opaque and easier it is to cover other paint.
In addition to the properties of paint, the process of applying it through flexible movements is rooted in science: speed, distance, angles, and release of tension all come into play. For a fine line and sharp cuts quickness is key, and the distance between the can and the surface matters to produce the desired effect. The can must be held no more than a few inches away from the target, or else the lines will flare and the thin paint will have a dotted texture. A thicker stroke, on the other hand, can be achieved by holding the can at an angle and farther away from the wall. Since the paint is released in a cone-like spray from cap to surface, flexing the wrist at various angles produces different shapes called conic sections, including circles and ellipses. Like playing an instrument, the flexible use of elbows, shoulders, and arm extensions are essential to prevent muscle fatigue and even injury.
Stemming from light absorption, colors influence the mental and emotional state of viewers who are lucky enough to observe a finished piece. When light hits a surface, the color we see is the wavelength of light that is most reflected off of it. Different shades stimulate our brain and often produce an emotional response. For example, a black and white combination may evoke nostalgia, while red often spurs a sense of aggression, passion, or even anger. When colors clash, they provoke confusion or reflection. When in harmony, however, a calming effect often occurs as the combination assuages the brain.
Graffiti is full of expression, yet it is also scientific in nature. Looking at the bigger picture, science and art are not a dichotomy at all. Artists employ scientific means to communicate complex emotions and messages through bold visuals. Likewise, scientists tap into the right side of their brains to find creative solutions to some of the world’s most complex problems. Thus, we see how art and science form a Venn diagram: distinct in nature yet overlapping at their core.
