The Ultimate Guide to UV light

Updated: Nov 4, 2020

We are all familiar with Ultraviolet light, whether it be from discos or the tanning beds – but are we educated on the power that we can harness from it? From the discovery of this invisible light, to the cutting-edge technology it is incorporated in today and its role in combatting Covid-19, here is your one stop shop to knowing all there is to know about UV light.

What is Ultraviolet light?

UV light is a wavelength of light on the electromagnetic spectrum. Electromagnetic radiation comes from sunlight and the spectrum of different wavelengths within this light is called the Electromagnetic Spectrum (EM). The different types of light include gamma rays, X-rays, infrared light (used in remote controls), radio waves (used in radios and television) and UV light. UV light is divided into three types – UVA (near UV), UVB (middle UV) and UVC (far UV), going from order of longest wavelength to shortest wavelength and in increasing energy. Of the UV light that reaches the equator, only 10% belongs to UV light and of that, 95% is UVA light and 5% UVB; UVC light is completely absorbed by the ozone layer according to Ozone Hole.

The discovery of UV light

This story, like most discoveries, was an accident. In 1800, whilst experimenting with the different temperatures of coloured light, a German astronomer, Frederick William Herschel shone light through a prism to split up the colours and placed a thermometer in front of each stream of light. He noticed that the temperature was the highest at the red end of the spectrum, so he decided to also measure just beyond the red stream of light, and he found that the temperature was even higher and there he discovered infrared light – an invisible light that opened the floodgate of research and knowledge on the electromagnetic spectrum.

A year later, a Polish physicist named John Ritter wondered if he could do the same on the other side of the spectrum. He realised that Herschel’s temperature method did not work and so used silver chloride; silver chloride tarnished black under the sun. So, through an experiment, he found that the violet end of the spectrum caused the silver chloride to tarnish the most and consequently found that a strip of light past violet caused an even more violent reaction and thus ultraviolet light was discovered. Both names of Latin origin, Infrared meaning below red and ultraviolet meaning beyond violet.

Where is it used?


UV light is used across many industries and in varying functions. You can find UV light in tanning beds, where artificial UV lamps are used to allow your body to mimic times when you are exposed to UVB light. Your body produces melanin with increased exposure to UVB light as a defence mechanism, consequently making your skin darker.


UV light is also used to inspect materials and surfaces, since different materials absorb UV differently. One of these is using fluorescence to identify materials in crime scenes, documents and forged bank notes using UV torches. Specifically, in crime scenes, fluorescein (a fluorescent dye) can be mixed with other chemicals and sprayed on surfaces; when UVA light is shone upon these surfaces, substances like blood and bone fragments can be detected.


The disinfecting power of UVC light has proved to be very useful in past 75 years, being used in water decontamination, sterilising the air and surfaces in hospitals and surgical theatres, and is recently being used in airports and train stations like Heathrow as a protective measure against Covid-19. The disinfection comes in the form of lamps and even automated robotic devices killing 99.9% of bacteria and virus where applied.

UV light and Coronavirus

With the recent coronavirus pandemic, UVC disinfection is becoming an increasingly attractive option to businesses and public services to add an extra layer of decontamination onto their cleaning regimes to give their users ease of mind and ensure a safer environment for working, commuting etc. According to the US National Academy of Science, UVC light has been shown to kill certain coronaviruses – “In a few laboratory experiments, UVC light has been found to destroy the ability of the SARS-CoV-2 virus to infect a host (for example, a mouse or a person), another indication that it is effective against germs. UVC light has also been shown to inactivate the genetic material in other coronaviruses.”

But the UVC light should only be used on surfaces and air, as the rays are damaging to skin and eyes and should be used alongside your normal cleaning and not as a substitute. There are many devices on the market that offer UVC light disinfection but know that they are of varying quality, if you are thinking of investing in some products, making sure they are tested and certified is especially important. (Our products are independently laboratory tested by SGS and certified to kill 99.9% of bacteria and virus)

If you’ve enjoyed this post, help spread the word (not the virus) by sharing and following our social media accounts. Check out our comprehensive range of UVC light products on our website.

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“We advocate the immediate installation of the safe and proven UR UVC technology. Existing technology that could be implemented now and has appropriate regulation and guidance" - NHS, University of St. Andrews