Blacklight Types and Uses
– Fluorescent black light tubes use a phosphor that emits UV-A light instead of visible white light.
– Blacklight blue (BLB) tubes have a violet filter coating that blocks most visible light.
– Blacklight (BL) tubes do not have a filter coating and produce more visible light.
– Bug zapper tubes use a UV-A emitting phosphor blend without a purple filter material.
– Incandescent black light bulbs use a UV filter coating like Woods glass.
– Black lights are required to observe fluorescence.
– Fluorescence has many practical uses.
– Black lights are used in forensics, counterfeit detection, and security authentication.
– UV light can be used to test for LSD, which fluoresces under black light.
– Tanning beds use strong sources of long-wave UV light.
– UV light is used for anti-counterfeiting measures, such as the green glow of the security thread on US $20 bills and the UV-visible design on Chinese passports.
Medical Hazards and Applications
– UV-A exposure can lead to skin aging, wrinkling, and skin cancers.
– UV-A can have negative effects on eyes in the short-term and long-term.
– High power UV-A sources pose a potential hazard to eyes and skin.
– UV-A is responsible for initial skin tanning.
– UV-A contributes to the progression of skin cancers.
– Woods lamp is a diagnostic tool used in dermatology.
– Ultraviolet light at a wavelength of approximately 365 nanometers is shone onto the skin to observe fluorescence.
– Woods lamp is used to detect fungal infections and distinguish fluorescent conditions.
– It can also be used to diagnose ethylene glycol poisoning.
– Woods lamp has been used to detect conditions such as tuberous sclerosis and erythrasma.
– Black lights produce light in the UV range, mostly in the longwave UVA region.
– UVA is the safest of the three spectra of UV light.
– High exposure to UVA has been linked to the development of skin cancer.
– UVA light does not cause sunburn but can accelerate skin aging and cause wrinkles.
– UVA light can destroy vitamin A in the skin and cause DNA damage indirectly.
Blacklight Types and Technology
– Fluorescent black light tubes have a phosphor coating that emits UV-A light.
– Blacklight blue (BLB) tubes have a dark blue filter coating that filters out most visible light.
– Blacklight (BL) tubes have no filter coating and have a brighter blue color.
– Bug zapper tubes use a phosphor that emits UV-A light without suppressing visible light.
– Different manufacturers use different numbering systems for black light tubes.
– Incandescent black light bulbs use a UV filter coating like Woods glass.
– Incandescent bulbs are cheaper but inefficient at producing UV light.
– Most of the light emitted by the filament is visible light, which needs to be blocked.
– Incandescent UV bulbs become very hot during use.
– The high running temperature reduces the lamp’s lifespan.
– High power mercury vapor black light lamps are made in power ratings of 100 to 1,000 watts.
– These lamps rely on the intensified and slightly broadened 350-375nm spectral line of mercury.
– Mercury vapor lamps use envelopes of Woods glass to block out visible light and harmful short-wavelength lines.
– They are more efficient UVA producers per unit of power consumption than fluorescent tubes.
– Mercury vapor lamps are commonly used for theatrical purposes and concert displays.
Fluorescent Minerals
– Fluorite, calcite, aragonite, opal, apatite, chalcedony, corundum (ruby and sapphire), scheelite, selenite, smithsonite, sphalerite, and sodalite are minerals that glow under UV light.
– George Stokes observed fluorescence in minerals in 1852 and named it after the mineral fluorite.
– UV lamps are commonly used in mines to visualize seams of fluorite and other fluorescent minerals.
– Hand-held UV lamps, like the UVP range, are used by geologists to identify sources of fluorite in mines.
– Some transparent selenite crystals exhibit an hourglass pattern under UV light and are also phosphorescent.
Safety and Security
– Black lights produce light in the UV range, mostly in the longwave UVA region.
– UVA is the safest of the three spectra of UV light.
– High exposure to UVA has been linked to the development of skin cancer.
– UVA light does not cause sunburn but can accelerate skin aging and cause wrinkles.
– UVA light can destroy vitamin A in the skin and cause DNA damage indirectly.
– Black light is commonly used to authenticate oil paintings, antiques, and banknotes.
– Legal banknotes have fluorescent symbols that only show under a black light.
– Counterfeit notes can be detected by their lack of fluorescent symbols and brightening agents.
– Fluorescent ink pens are used to invisibly mark items for security purposes.
– Black light can be used to search for these security markings if the marked objects are stolen. Source: https://en.wikipedia.org/wiki/Blacklight
A blacklight, also called a UV-A light, Wood's lamp, or ultraviolet light, is a lamp that emits long-wave (UV-A) ultraviolet light and very little visible light. One type of lamp has a violet filter material, either on the bulb or in a separate glass filter in the lamp housing, which blocks most visible light and allows through UV, so the lamp has a dim violet glow when operating. Blacklight lamps which have this filter have a lighting industry designation that includes the letters "BLB". This stands for "blacklight blue". A second type of lamp produces ultraviolet but does not have the filter material, so it produces more visible light and has a blue color when operating. These tubes are made for use in "bug zapper" insect traps, and are identified by the industry designation "BL". This stands for "blacklight".
Blacklight sources may be specially designed fluorescent lamps, mercury-vapor lamps, light-emitting diodes (LEDs), lasers, or incandescent lamps. In medicine, forensics, and some other scientific fields, such a light source is referred to as a Wood's lamp, named after Robert Williams Wood, who invented the original Wood's glass UV filters.
Although many other types of lamp emit ultraviolet light with visible light, black lights are essential when UV-A light without visible light is needed, particularly in observing fluorescence, the colored glow that many substances emit when exposed to UV. Black lights are employed for decorative and artistic lighting effects, diagnostic and therapeutic uses in medicine, the detection of substances tagged with fluorescent dyes, rock-hunting, scorpion-hunting, the detection of counterfeit money, the curing of plastic resins, attracting insects and the detection of refrigerant leaks affecting refrigerators and air conditioning systems. Strong sources of long-wave ultraviolet light are used in tanning beds.
