The ultraviolet flashlight has recently appeared on the market, but has already gained wide popularity among specialists. The device works on LEDs and allows you to see in its light beam what the human eye does not distinguish, not armed with technology. By aiming such a flashlight at an object of interest, you can see many unexpected things. The UV spectrum of the flashlight opens before you an exciting world of objects and phenomena never seen before. The device is produced in models different variations: pocket, key rings, forehead, stationary.
What is it needed for
Why do you need an ultraviolet flashlight - this question often arises from users unfamiliar with the magical functions of this amazing device. Our eyes only see a limited spectrum of colors. Most useful and important information is beyond human vision. In order to identify color marks invisible to the human eye, a UV flashlight has been created.
More recently, scientists have developed it with special properties. It is a substance that cannot be distinguished by human sight. It is worth directing the light beam of an ultraviolet flashlight at it, and all drawings, pictures and texts applied by means of fluorescent paint immediately come to life. Everything becomes visible, just like ordinary objects. 
Ultraviolet glow
Expert opinion
Alexey Bartosh
Ask an expertThe ultraviolet light beam is also invisible to human eyes. By aiming it at objects, you can see the almost invisible. Having bought an ultraviolet flashlight, its owner uses it to advantage as a detector to detect various substances, phenomena and objects that are sensitive to UV radiation.
What can be seen in the rays of an ultraviolet flashlight:
- Government-issued banknotes have many protection methods. This includes: special fibers, watermarks, special printing, errors, effects, special paints, metallized stripes. This list can be continued indefinitely - there are so many security methods used in the manufacture of banknotes. Most of the protection signs glow under the rays of ultraviolet radiation of a certain light wave. Checking money becomes easy. Receiving a lot of bills every day in the process of work in trade, in the market or in the market, you need such detectors. Of course, you should prepare well by studying all the features of banknotes. Modern counterfeiters have phenomenal knowledge in the field of chemistry and physics. Today's banknote counterfeiters effectively counterfeit even the most sophisticated security that not every expert and forensic scientist can recognize.
- Manufacturers and vehicle drivers are well aware of how difficult it is sometimes to find leaks of working fluid from a car, assembly, or mechanism. Diagnostics is carried out by adding fluorescent paint to the working fluid. The location of the leak is immediately visible when the beam of an ultraviolet flashlight is pointed at it. Car enthusiasts also check anti-theft markings in this way.
- Powerful ultraviolet lights are successfully used in geology and speleology. Ultraviolet rays show the impregnation of valuable minerals in rocks... In a similar way, the study of fossils is effectively carried out, the search for amber, which is clearly visible in the light of an ultraviolet flashlight. For serious searches, you should arm yourself with a professional flashlight, which costs more than pocket models.
- Many enterprises of the military-industrial complex and others use protective marking of their products. These brands become visible only when exposed to the beam of an ultraviolet flashlight directed at them. In such rays, you can read the inscriptions made with special invisible markers like Edding.
- Hunters appreciate the UV flashlight and buy it with pleasure. The wounded beast leaves blood stains on the trail. Blood is excellent at absorbing ultraviolet rays. By directing the light of an ultraviolet flashlight onto the trail, the hunter clearly sees spots that are darker on any background. The capture of a wounded animal is greatly facilitated.
- Traces of various biological fluids from human body, for example, traces of semen, saliva, phlegm when coughing are perfectly visible in the beam of an ultraviolet flashlight. The work of experts involved in the fields of traceology and forensic science is greatly facilitated with this device.
Checking banknotes with an ultraviolet flashlight
Antique coats of arms and stamps found on the carbine with an ultraviolet flashlight
Checking the leakage of working fluid from the car engine with an ultraviolet flashlight
Traces of the criminal's biological fluids, identified with an ultraviolet flashlight
Search by a hunter of a wounded animal with an ultraviolet flashlight
Amber found with a UV flashlight
Many areas of industrial production, scientific developments with implementation in real life ultraviolet lights have received invaluable support for their activities. In the light of ultraviolet radiation, many objects, phenomena, texts, invisible inscriptions or drawings that have been hidden from the eyes of mankind for many centuries have become visible.
How to choose
Each flashlight with ultraviolet light has a different wavelength of light. Spectrum ultraviolet radiation, able to see hidden information, is also different for all lights. Lantern designs are assembled from different amounts LEDs. This is the main factor in determining the appropriateness of using an ultraviolet flashlight in different areas production and personal use.
Human vision perception diagram of visible light and ultraviolet radiation When choosing an ultraviolet flashlight, each user should rely on the following characteristics of these products:
- It is best to catch insects and determine biological fluids with instruments with a capacity of 300-380 nanometers, nm.
- You can check banknotes with a device with a wavelength of 385 nm. A BlackLight fluorescent lamp is also required.
- Invisible markings will become visible at 385-400 nm. You need a powerful UV flashlight.
- For simple entertainment, a pocket ultraviolet flashlight or key fob is enough. You can read fluorescent paint in nightclubs with any of them.
Expert opinion
Alexey Bartosh
Specialist in repair, maintenance of electrical equipment and industrial electronics.
Ask an expertIt is necessary to purchase an ultraviolet flashlight for a specific purpose. What can be seen by one device will not be seen by another. It is necessary to study the subject of consideration in advance and find out all its physical and chemical characteristics.
How to determine the UV wavelength of a flashlight
It is necessary to take a banknote of 5,000 rubles of the 1997 sample, directing a beam of an ultraviolet flashlight at it.
Flashlight with a wavelength of 365 nm will illuminate all the protective UV elements. The glow is pale white. 
Verification of the authenticity of a 5000 ruble note with an ultraviolet flashlight with a wavelength of 365 nm
A flashlight with a wavelength of 375 nm to 385 nm will illuminate all protective UV elements, except for the oval with a red stripe with right side bills. The glow is pale purple. 
Verification of the authenticity of a 5000 ruble note with an ultraviolet flashlight with a wavelength of 375 nm
A flashlight with a wavelength from 395 nm to 405 nm will illuminate only the protective fibers of the bill. The glow is bright purple. 
Checking a 5000 ruble bill with an ultraviolet flashlight with a wavelength of 395-405 nm
With your own hands
Every master who knows how to hold a screwdriver can independently make an ultraviolet flashlight at home. You must perform the actions in the following sequence:
- Buy a standard one - usually there are 8 of them.
- Separately buy 8 UV LEDs of the same size. Wavelength 360-400 nm, current 500-700 mA.
- Remove the protective glass.
- Unsolder ordinary LEDs.
- Solder the purchased UV LEDs into the circuit.
- Reinsert the protective glass.
UV LED 395nm, 10W, 45mil, 900mA current 
LED flashlight with glass removed 
Soldering diodes, removing conventional, installing ultraviolet The UV light is ready. You can surprise him with the capabilities of your family, friends, acquaintances at a party. In the light of the device, you can see a lot of interesting things: dyes and make-up, security information on banknotes, detect cracks, invisible inscriptions on devices, car engines. Good luck with your creativity!
Ultraviolet is part of the spectrum electromagnetic radiation, which is beyond the boundaries of our perception. Simply put - invisible radiation... But not really. The light we see is limited to wavelengths between 380 nm and 780 nm (nanometers). The wavelengths of ultraviolet or ultraviolet radiation are in the range from 10 nm to 400 nm. It turns out that we can still see ultraviolet light - but only a small part of it, located in a small interval between 380 and 400 nm.
Everything. Dry facts are over, interesting facts begin. The fact is that this barely visible radiation actually plays a huge role not only in the biosphere (we will certainly tell you about this separately), but also in lighting. Simply put, ultraviolet light helps us see.
Ultraviolet and lighting
The main application of ultraviolet light is found in lamps. Electrical discharges cause the gas inside a fluorescent lamp (or compact fluorescent lamp) to glow in the ultraviolet range. In order to obtain visible light, a special coating of a material is applied to the walls of the lamp, which will fluoresce - that is, glow in the visible range - under the influence of ultraviolet radiation. This material is called a phosphor, and manufacturers are constantly working to improve its composition in order to improve the quality of the visible light received. That is why today we have a good selection of fluorescent lamps, which not only outperform conventional incandescent lamps in energy efficiency, but also produce almost full spectrum light, which is quite pleasing to the eye.
What other uses for ultraviolet radiation can be?
Exists whole line materials that can glow in ultraviolet light. This ability is called fluorescence - it is possessed by many organic substances. In addition to it, there is also the so-called phosphorescence - its difference is that the substance emits light with a lower intensity, but continues to glow for some time (often quite long - up to several hours) after the cessation of exposure to ultraviolet radiation. These properties are actively used in the manufacture of various "glow in the dark" items and jewelry.
Market building technologies does not stand still and periodically surprises consumers with its novelties. One of them is invisible in daylight ultraviolet paint, which is widely used by decorators and designers today.
Its name involuntarily evokes fantastic associations, although in fact it is quite a common material for interior decoration.
Views
The range of such products can be roughly divided into two groups:
- luminescent;
- fluorescent.
Each has its own special properties that determine the specifics of their application, as well as a wide range of colors. These materials are based on insoluble and opaque alkyd or water-based pigments. Afternoon on light surfaces they are practically invisible, at the same time on dark surfaces they look like whitish traces.
Let's dwell a little on pigments, since it would be good to know more information about them when painting any surface. For example, each coloring agent has such a characteristic as hiding power, i.e. how much material is required to paint the conditional amount of a unit of area.
If you take an ultramarine pigment, you will need about 50 g / 1 m 2. By the way, not many people know from which mineral ultramarine paint is obtained: natural from lapis lazuli, but artificially- from a mixture of kaolin, Glauber's salt, soda, sulfur and coal.
Azure can be used as a stand-alone shade or used to enhance color. Now you know what ultramarine paint is made of - from which mineral it was first obtained, and you can always give the correct answer.
Fluorescent
- Invisible paint, glowing in ultraviolet light, brightly acidic shades.
- Colors of paint:
- lemon;
- yellow;
- blue;
- blue;
- red;
- brown;
- purple;
- mustard;
- purple;
as well as other colors.
- Invisible black acrylic paint does not glow in ultraviolet rays, but it makes it possible to create 3D shadows in drawings.
- The material is used for design:
- living quarters;
- clubs;
- restaurants;
- and decoration of textiles and sports equipment;
- signal signs.
Luminescent
This type of invisible paint can accumulate light energy, which then gradually gives off, glowing in the dark.
The duration and intensity of the glow depends on:
- pigments and their quality;
- intensity and time of light irradiation of the material;
- base layer colors;
- degree of illumination.
In normal light, it has a pale greenish tint, but in the dark it begins to glow with a bright corresponding color.
Luminescent paints can be used:
- yellow;
- blue;
- green;
- purple;
- orange;
- red.
Invisible fluorescent paints can only glow with these colors:
- blue-green;
- green-yellow;
- blue.
The material has found its application in interior decoration, it is applied with their own hands on wallpaper, as well as others decorative coatings, they are decorated with decorative elements, including shades, candlesticks and vases.
Places of application
For interior
Paint on acrylic base specially designed for the protection and decoration of indoor wallpaper. Such materials dry very quickly, have chemical and mechanical resistance, and high elasticity. Each comes with instructions for use.
Special additives in the composition prevent mold and mildew from appearing on the painted surface.
Used for ceilings and walls made of dense and porous materials:
- bricks;
- cement-lime plasters;
- concrete;
- wallpaper.
For metal
They form a glossy transparent finish.
Possess:
- weather resistance;
- increased strength;
- resistance to oils;
- detergents;
- some organic solvents.
Have high level drying, are used for and outside the premises. They are used in airbrushing, auto-tuning, for painting car disks, in decor and design of exteriors and interiors.
Advice: when using fire-retardant paints for metal Polistil.
Basics for paint
Currently invisible luminescent and fluorescent paints can be alkyd and water based.
Consider their characteristics below:
- Water-based materials are non-toxic, their price is quite affordable, they do not have a specific smell, therefore they are much more often used to decorate the interiors of residential premises and entertainment establishments. In addition, they can be successfully used for the design of facades and other finishing works outside buildings.
The paints are resistant to external influences and will not be washed off by rain and snow. They should be applied on previously degreased wood, glass, metal, woven and stone surfaces. - The alkyd base is more resistant to various influences, in addition, it is not washed off from surfaces detergents... Due to the toxic fumes during drying, such paints should be used for external design.
For example, use the compositions when decorating the facades of buildings that will acquire the original appearance with appropriate illumination. They are often used when decorating entrances to restaurants, sports clubs, discos, bars and other similar establishments.
Output
If you want to give the interior of a room or house from the outside original view, use special glowing paints for this. They are of two types - fluorescent and luminescent, which differ from each other in special characteristics. The video in this article will help you find Additional information on this topic.
Few people know, but a grandiose light show is constantly happening around us, which we, unfortunately, do not see. The fact is that many arthropods (insects, spiders, etc.) have one interesting feature: they glow in ultraviolet light.
Fireflies and other animals endowed with bioluminescence ability glow due to chemical reaction flowing in special organs of the glow. This phenomenon has been seen by many. But scorpions, some spiders and a number of related organisms are capable of producing a blue-green glow using the phenomenon of fluorescence.
Crab spider fluorescence Exoskeleton molecules ( outer shell) these animals absorb ultraviolet light (320-400 nm) invisible to our eye, after which they re-emit ultraviolet light into the bluish light visible to us.
It turns out that many arthropods glow under ultraviolet light. Photographer Niki Bey (his photographs along with mine are used in the article about) made a series of wonderful pictures of bioluminescence of arthropods, which I used to illustrate this text.
Why do arthropods glow in ultraviolet light?
In short: for many of the fluorescent animals, we don't know why. There is a lot of literature about the glow of various arthropods, the main idea of which can be reduced to: “Wow! It shines !!! ".
Kivsaki also fluoresces in UV light. True, for scorpions, the mechanism of this glow has been studied in more detail.
In scorpions, the so-called cuticular fluorescence is observed. It involves two compounds found in the epicuticle of a scorpion: beta-carboline and 4-methyl, 7-hydroxycoumarin. Coumarin, by the way, is used in perfume or as a cinnamon-flavored flavoring agent.
Scorpion fluorescence is a very beautiful phenomenon There are a couple of hypotheses regarding the purpose of scorpion fluorescence. Most insects can see ultraviolet light, so their world looks very different from ours.
Spider Heteropoda sp. human and insect eyes According to some experiments, scorpions can use the ability to absorb ultraviolet light to seek shelter. During the experiment, the scorpions were put on tiny glasses that prevented the animals from seeing with their eyes. But as soon as the UV light was turned on, the animals quickly found suitable hiding places. Apparently, orientation was due to signals received from surfaces that absorbed ultraviolet light (published in the journal Animal Behavior).
Perhaps ultraviolet light helps scorpions navigate According to another version, the glow of scorpions in ultraviolet light is a relic of the early Devonian period, when the earth was inhabited by giant scorpions and centipedes. Substances accumulated in the integument, capable of absorbing ultraviolet light and emitting blue light, could protect ancient arthropods from sunburn... At least in young plant seedlings, it is coumarin that acts as a sunscreen.
Since ancient times, mankind has tried to invent invisible or, as they are also called, sympathetic ink that is not visible to the eye under normal conditions, but begins to appear after exposure to any chemical elements, heating, ultraviolet rays... They were used to send secret messages, preserve important information, secret correspondence.
In ancient times, these were commonly available substances that could be found in every home. For example, great success used secret writing, carried out with milk, lemon juice, rice water, wax, apple and onion juice, rutabaga juice. Later, there were options for making sympathetic ink using aspirin tablets, copper sulfate, iodine, washing powder.
Modern ultraviolet ink
Science does not stand still, so nowadays you will not surprise anyone with invisible industrially produced ink. Compositions that glow underneath are very popular. ultraviolet lamps... There are even UV ink pens on sale, which you can find in spy giz stores.
An alternative to such a pen can be invisible anti-fake paints and pigments. They are powdery substances that can be used to mark banknotes, securities, clothing. In daylight, the powder is completely indistinguishable, but in ultraviolet light, every grain or powder becomes visible.
How to make invisible fluorescent ink at home
As a good fluorescent ink, you can use regular washing powder, which contains optical brighteners. By diluting the powder with a little water, you can begin to write a secret message. The dried solution will not leave prints on paper, but it will look great in the light of an ultraviolet lamp.
Can also be purchased separately. As a rule, they are used to impart a whiteness with a bluish tint to clothing, fabrics, and paper intended for printer printing. The powder can also be used to create a sympathetic ink. This ink will develop on all types of paper.
Another way to make invisible ink is by using aspirin tablets and rubbing alcohol. Dissolve 2-3 aspirin tablets in a small amount of alcohol. If a precipitate remains during dissolution, the liquid should be filtered. After that, you can begin to secret writing. This ink does not glow on all types of paper; this method is not applicable if you will write on printer paper.
You can also use the following drugs to prepare ink, which you can try to get at the pharmacy:
- curcumin;
- quinine sulfate;
- trypoflamine.
You can also use the sodium salt of fluorescein, but its native color can stand out on white paper after application, so this ink is not invisible.