What is a black light flashlight actually used for?

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If you grew up in the 90s, you probably remember the neon glow of black lights, which were popular at the time. Maybe you had one in your bedroom, a friend had one, or a local place bathed its halls in bold hues. You can still find them today, although not as widespread, in indoor mini golf parks, laser tag arcades, arcades, etc. But there is another, more practical use: a flashlight. Black light flashlights, technically UV flashlights, are nothing more than portable or portable lamps that emit ultraviolet light instead of the warm hues of a traditional light bulb. Although they have many uses, UV flashlights are generally used to detect traces of materials or elements.

A UV flashlight is simply equipped with a UV bulb or LED that emits UV radiation. Scientifically, UV light is an invisible wavelength of the electromagnetic spectrum, located between visible light and X-rays. They are shorter than visible light but longer than X-rays, on the order of 100 to 400 nanometers. Natural UV comes from the sun and comes in three types: UV-A, UV-B and UV-C. UV lights or black lights emit UV-A, the longest and most common of the three wavelengths.

The old-school style of black lights is a fun and whimsical form of decoration, excellent for both arcades and arcades. But you may have also noticed that UV light has the power to illuminate various stains, element traces, and reactive materials. When something glows under UV light, it is considered “fluorescent,” meaning it absorbs the wavelength of light or radiation and then reflects (re-emits) it as a longer wavelength. Humans, animals and rodents are also known to change color under UV light, known as biofluorescence. These properties would otherwise be invisible to the human eye and undetectable. UV lights make all of this observable.

This makes them ideal candidates for investigations in various contexts, professional or personal. UV flashlights can help identify otherwise invisible stains, such as pet stains, food or chemical spills, blood and other liquids, the latter of which is very useful in forensics and at crime scenes.

There are also many similar, but auxiliary, uses. China has introduced agricultural robots far more sophisticated than simple tractors, which use UV light and cameras to detect and report pests and crop diseases. HVAC technicians can use a UV flashlight to detect system leaks, art experts and inspectors can use them to authenticate or treat paintings by studying the fluorescent properties of older paints, and miners or rock collectors use them to discover rare minerals. Additionally, UV lights can help check the cleanliness of spaces like hotel rooms or apartments, find UV-reactive insects or even identify counterfeit currency and documents – legitimate versions are marked with fluorescent ink to indicate they are genuine.

As long as you don’t point a UV flashlight directly at anyone for long periods of time, it should be safe to use. Overexposure to UV rays is what you call sunburn. Although the risks are lower, prolonged exposure to UV-A from manufactured lamps can cause sunburn and skin damage, increasing the risk of cancer. You should avoid shining UV lamps closely onto bare skin, especially if they are classified as a high-power light.

You should also avoid pointing them at anyone’s eyes or your own eyes, which means not looking directly at the bulb or light source. This can lead to what is called photokeratitis, which is a painful sunburn on the cornea. It’s temporary in most cases but it hurts, so it’s still not something you want to experience or have anyone else deal with. Wearing safety glasses or polarized glasses is the ultimate defense. Likewise, modern cameras are sometimes equipped with a UV protection lens filter to protect the camera lens and reduce haze and light adjustments due to UV rays.

A good practice is to turn the light on only when necessary, such as to detect minerals, stains or chemicals on specific surfaces, rather than leaving it on and walking around with it. Interesting note: Phone disinfection machines actually work by using UV-C, another form of ultraviolet light, to kill bacteria and viruses.