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LuxeSci Show Notes: S2E10 - Spray Paint and Street Art

Welcome to LuxeSci, a podcast to re-ignite your wonder by exploring the science behind luxury items.  This week’s topic is especially timely.  We will be going on a tour in Athens of some amazing street art, and street art is usually done with…spray paint.  That’s right, this week’s episode is going to take a left turn to examine something that many might not associate with luxury (although, the famous street artist, Banksy uses spray paint).  I would argue that street art is the epitome of luxurious, trying to turn our ordinary world into something extraordinary.

So Dimos - have you ever spray painted anything?

  • Background on Street Art

  • You could argue that the history of street art goes back to the earliest cave paintings. 

  • The are many examples of ancient graffiti from Ancient Greece and Rome and those are usually carved into surfaces

  • Some of the most interesting ones are from Greek and Roman tourists in Egypt

  • Some of the inscriptions include: “i visited here and i didn’t like anything except the sarcaphogus” and “ I cannot read the writing”

  • What we more commonly think of as graffiti or street art likely had it’s beginnings in the 1920 and 30s in NYC where rival gangs used name-based tags to mark the territory they controlled

  • Around the same time, art murals were being introduced in Southern Calfornia’s cities

  • Street art really kicked off in the 1960s when NYC had a ton of vacant lots and boarded-up buildings, etc and that became the canvas for creative kids, probably first in Spanish Harlem

  • In the 1980s, street and graffiti found its way into art galleries and museums, with Keith Haring and Jean-Michel Basquiat being some of the first.

  • Street art - more intentional and uses elements of graphic design and more imagery

  • Graffiti - usually not commissioned and is usually text based


1) What is spray paint?

Origins  (from

The concept of an aerosol originated as early as 1790 when self-pressurized carbonated beverages were introduced in France. In 1837, a man called Perpigna invented a soda siphon incorporating a valve. Metal spray cans were being tested as early as 1862. They were constructed from heavy steel and were too bulky to be commercially successful.

In 1899, inventors Helbling and Pertsch patented aerosols pressurized using methyl and ethyl chloride as propellants.

Then… (from wikipedia)

Erik Rotheim an engineer from Oslo Norway studied in ETH Zurich as a chemical engineer and established his own company in Oslo during 1925. He submitted an application for an aerosol spray can in October 1926. The can could dispense different fluids using a chemical propellant. The Norwegian patent was granted in June 1929. He filed the United States patent application on 30 September 1927 and it was approved on 7 April 1931.[1] In 1998, the Norwegian post office issued a stamp celebrating the Norwegian invention of the spray can.

Surprisingly if you research Edward Seymore you will find the company website says that Spray paint was invented in 1949 by Edward Seymour who thought to use an aerosol spray to dispense paint however it is more correct to attribute the innovation to the first canned paint that could be deposited using an aerosol.  In 1949, he demonstrated the color  aluminum designed for finishing radiators on a large scale quickly; his wife is credited with asking him to release other colors. Seymour was simply piggybacking on this innovation as a way to showcase his own product, but he was so intrigued by this new method of paint delivery that he directed his company, Seymour of Sycamore, to dedicate considerable resources to exploring its potential.

Around the same time Seymour was working on his contributions to spray paint, Krylon and Crown Holdings Inc. were each developing new can designs that eventually gave rise to the metal cylinders we use today [source: Sattler]. They were smaller, lighter, cleaner and applied an even coat faster than a brush or roller could, making those small paint projects around the house a lot more manageable. And once the manufacturing industry discovered its benefits, spray paint went from a resourceful and useful invention to a full-blown industrial boon.

I checked and Seymore is still around with an amazing supply of paints for just about any use mainly in the professional area, especially for high performance primers and even paints for engine blocks. They also do athletic field marking paints. Krylon is however much more directed to the home hobbyist 

2) How does the aerosol work (scientifically)

It is mainly just paint in a can with a gas that forces the paint through the dip-straw and out the nozzle. There is a pea which agitates the paint to avoid clumpy delivery as it comes out the tube to the nozzle.


Chlorofluorocarbons until 1978 due to ozone hole

Hydrocarbons until 1980s due to smog regulationsHydrofluorocarbons till now.

As the paint leaves the nozzle the pressure difference causes the paint stream to atomize., each paint particle is positively charged relative to the other particle creating a repulsive action on the powder leaving the nozzle. This allows for a uniform spread of paint

3) What are the hazards associated with spray paint (again from a scientific perspective, such as what volatile organics are and why they are dangerous to humans)

Spray Paint as a Narcotic?

The reason paint is viscous is because it contains a solvent, usually the hydrocarbon toluene, that evaporates quickly at room temperature. Two things happen as the solvent evaporates: The paint dries, and chemical vapors are released. These vapors, if inhaled, can have intoxicating and even hallucinatory effects. In addition to solvents, spray paints contain aerosols, which also release harmful chemicals. This double-whammy, coupled with relatively easy access (most retailers will not sell to minors) makes spray paint the product of choice for those looking to get high.

Rustoleum for example: Contains: TOLUENE, XYLENE AND ACETONE.

From: CDC

Acetone can cause respiratory irritation but is not known to be accumulated in the body. It can over long periods of time cause kidney, liver, and nerve damage. Not considered carcinogenic at this time.

Toluene (C₆H₅CH₃) is a colorless liquid with a sweet, pungent odor. The primary target organ for Toluene is the central nervous system. Exposure to toluene can cause eye and nose irritation, tiredness, confusion, euphoria, dizziness, headache, dilated pupils, tears, anxiety, muscle fatigue, insomnia, nerve damage, inflammation of the skin, and liver and kidney damage. 

Other occupational risks include exposure to Technicians who work in nail salons, Construction workers who use paint, adhesives or solvents, Workers involved with the production of gasoline.

Xylene is an aromatic hydrocarbon widely used in industry and medical technology as a solvent. It is a colorless, sweet-smelling liquid or gas occurring naturally in petroleum, coal and wood tar, and is so named because it is found in crude wood spirit (Gr. xy`lon- wood).[1] It has a chemical formula of C6 H4 (CH 3)2 and is referred to as “dimethyl benzene” because it consists of a six-carbon ring to which two methyl groups are bound.

It depresses the Central Nervous System and causes the same symptoms as Tolulene except at a more extreme level.

Fun fact….what is the Krylon color of the year for 2023?

Spanish Moss.

Largest spray paint mural:

2016 by artist Avi Tal in Israel. 2,038.96 m^2

Two years ago, many were stunned by the illustrious mural that lined Olympic Boulevard at the 2016 Rio Olympics, a creation rendered by artist Eduardo Kobra and his team of spray paint artists.

Titled “Etnias”, the art piece made headlines for stretching 560-feet long, and measured a feat that earned the talented group the record for the Largest spray paint mural by a team. 5,728.62 m² (61,662 ft² )

  • Science

  • Say, hypothetically, you live in a city and the side of your property keeps getting tagged and then the city bugs you to paint over it or you will get a fine, and it keeps happening.  Perhaps you would want to try and figure out who is doing the tagging.

  • One way that you to connect the actual spray paint and the person who sprayed it is with a technique called Attenuated Total Reflectance Fourier Transform Infrared (ART-FT-IR) spectroscopy

  • This technique is actually used often in our last podcast episode, art conservation and restoration, to identify the chemical makeup of paints, fillers, and binders

  • We’ve talked about spectroscopy a fair bit on the podcast, as a refresher, spectroscopy is simply the study of the interaction of light and matter.

  • Measuring the spectra (electromagnetic radiation) of matter to get information concerning the structure and properties of that matter.

  • The “attenuated total reflection” portion of this technique allows for samples to be directly analyzed in either liquid or solid state

  • Quantifies the changes to an internally-reflected infrared beam after it comes in contact with the sample

  • The beam is focused on a crystal with a high refractive index and the sample is put onto the crystal

  • In the parts of the spectrum where the sample absorbs energy, the wave from the beam will be altered or attenuated and this is measured by a detector

  • Fourier transformed infrared portion is a technique that is used to get a spectrum from either the emission or absorption of a sample (any phase)

  • What comes out is a specific pattern that can either be compared to a database of patterns or analysed on its own for molecular components of the sample

  • Scientists from the Department of Forensic Science at Punjabi University used this technique to see if they could match spray paint patterns from graffiti and samples collected from a suspect.

  • This was published in 2021 in the Journal of Forensic Sciences

  • What they found was spray paint on paper or fabric was hard to identify because it resulted in poor spectra (pattern)

  • Cement walls were also not conducive to this type of analysis because cement go scraped off along with the paint and that caused interference

  • But for floor, gloves, metal, plastic, leather shoes, tile wood and hair, they could match the spray paint from the graffiti to the source paint can.

  • Even if you can’t identify who tagged your house, chances are you’d like to get rid of it, or perhaps you’re responsible for an historic site and it gets vandalized (not all street art is welcome I guess).  How would you do that?

  • Researches from the University of Canberra and the Australian National University have a solution..and it’s just as practical for the everyday home owner as the FITR spectroscopy

  • In their research published in Optics Express (which sounds like a eye glass shop), they looked at using femtosecond lasers to clean a variety of  colors of spray paint off of Moruya granite, which is often used for monuments and sculptures in Sydney and New South Wales (shout-out to our two Aussie listeners).

  • Pulsed lasers - lasers that emit light in the form of optical pulses and not continuously

  • Popular pulsed lasers are nanopulsed lasers - pulses in the nanosecond range

  • These are already being used in the treatment of historical stonework are are good at removing red, blue and black paints

  • Not as good at other colors, particularly silver and they may induce discoloration in the stone when done with granite

  • Femtopulse lasers break molecular bonds of the material being removed without passing a shockwave or heat into the source material 

  • Particularly good for materials such as granite, that has minerals with different heat sensitivity

  • The researchers successfully removed blue, green, red, yellow and silver paint from the granite without damaging it.

  • Now some kind bad news.  A study published in 2022 in Environmental Chemistry Letters by Xu, et al found that spray paint is a source of microplastics in soils

  • Microplastics - common types include polyethylene, polypropylene, polyamides, polystyrene, polyvinyl chloride and the have different sizes, shapes and densities

  • Tiny plastic particles that result from both commercial product development and the breakdown of larger plastics

  • Paints are a likely source of microplastics since they contain polymer binders as a key ingredient

  • The authors of this paper came up with a new separation protocol to separate potential paint-derived microplastics from the soil.  This is because paint-derived particles (fall-out from the aerosols of the spray paint) would be denser than most microplastics that are currently monitored

  • One step was to use xylene in the extraction since most polymers in paints are partially or totally soluble in xylene, which is why it’s used in paint thinner

  • The used a soil samples from near walls with graffiti in Berlin 

  • They found between 1500 and 30,000 particles per gram of soil of microplastics, with the highest concentrations found in the top layers of soil

  • The authors recommend continual monitoring of these microplastics in soil and monitoring spray painting of larger structures to reduce environmental contamination risk

  • One last fun item so we don’t end on a bummer

  • Neelam Singh et al published in 2018 in Scientific Reports on a paintable battery

  • Fabricated rechargeable Li-ion batteries by a multi-step spray painting technique of all the components

  • Choose spray paint since it’s easy to do and you can go small-scale in spray cans or industrial spray guns

  • Formulate component materials into liquid dispersions and they chose Lithium Cobalt Oxide and Lithium Titanium Oxide

  • They sprayed the battery on a number of different surfaces, including spelling RICE onto a ceramic mug

  • They say the power in this is to link the batteries (lego unit) and then integrate that into other devices, such as solar cells


  • Spectroscopy - study of the interaction of light and matter

  • Pulsed lasers - lasers that emit light in the form of optical pulses and not continuously

  • Microplastics - Tiny plastic particles that result from both commercial product development and the breakdown of larger plastics

Cocktail party facts

  • What’s one way to identify whose paint was used to spray graffiti?

  • What is one environmental down-side to spray paint?

  • How can conservators remove spray paint from stone?

Thank you for listening to this episode of LuxeSci.  Please tell at least two people about this podcast.  This is the best way to help us get noticed and find new listeners.  A special thanks as always to my audio engineer Dimos.  Our theme music is Harlequin Mood by Burdy


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