Blacklight paint
Encyclopedia
Blacklight ink or blacklight-reactive Ink is ink
Ink
Ink is a liquid or paste that contains pigments and/or dyes and is used to color a surface to produce an image, text, or design. Ink is used for drawing and/or writing with a pen, brush, or quill...
that glows under a black light
Black light
A black light, also referred to as a UV light, ultraviolet light, or Wood's lamp, is a lamp that emits ultraviolet radiation in the long-wave range, and little visible light...
, a source of light whose wavelengths are primarily in the ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
. The paint may or may not be colorful under ordinary light. It is also known as luminous paint
Luminous paint
Luminous paint or luminescent paint is paint that exhibits luminescence. In other words, it gives off visible light through fluorescence, phosphorescence, or radioluminescence.-Fluorescent paint:...
or fluorescent paint.
Blacklight paints can be mixed with similar shades of normal pigments, "brightening" them when viewed in sunlight. DayGlo is a tradename, and a common name for these sorts of paints.
The invention of fluorescent paints is attributed to Robert Switzer
Bob Switzer
Robert C. Switzer usually known as Bob Switzer was the co-inventor along with his brother Joe Switzer of the first fluorescent paint which he called "Day-Glo"....
, who was confined to a dark room after a fall, and his brother Joseph, who was a chemistry major at UC Berkeley, in 1934. They took a black light
Black light
A black light, also referred to as a UV light, ultraviolet light, or Wood's lamp, is a lamp that emits ultraviolet radiation in the long-wave range, and little visible light...
into the storeroom of their father's drugstore looking for naturally fluorescent organic compounds and from that developed paints.
Blacklight paints and inks are commonly used in the production of blacklight poster
Poster
A poster is any piece of printed paper designed to be attached to a wall or vertical surface. Typically posters include both textual and graphic elements, although a poster may be either wholly graphical or wholly text. Posters are designed to be both eye-catching and informative. Posters may be...
s. Under daylight, the ultraviolet light ordinarily present makes the colors especially vivid. Under blacklight (with little or no visible light present), the effect produced can be psychedelic
Psychedelic
The term psychedelic is derived from the Greek words ψυχή and δηλοῦν , translating to "soul-manifesting". A psychedelic experience is characterized by the striking perception of aspects of one's mind previously unknown, or by the creative exuberance of the mind liberated from its ostensibly...
. The inks are normally highly sensitive to direct sunlight and other powerful light sources. The fluorescent dyes cause a chemical reaction when exposed to high intensity light sources (HILS) and the visual result is a fading in the colors of the inks. With paper, significant visible change in the color saturation can typically be observed within 45 minutes to one hour of exposure to the HILS. To date, there is no absolute method to prevent this phenomenon, although certain laminations, lacquer coatings and glass or plastic protective sheets can effectively slow the fading characteristics of the dyes.
Other common usage of the blacklight inks is in security features of money notes, various certificates printed on paper, meal coupons, tickets and similar things that represent a value (monetary or otherwise). The blacklight printed figures used for this purpose are usually invisible under normal lighting, even when they are exposed to direct sunlight (which contains ultraviolet light) but they show up glowing when exposed to blacklight source. This defeats simple and inexpensive attempts to counterfeit them by scanning the original using a high resolution scanner and printing them using an inexpensive high resolution printer (most if not all inexpensive printers don't allow using blacklight inks for printing) and no special equipment is needed to verify the presence and correctness of this feature (an inexpensive blacklight source being all that is required). Some coupons and tickets use colorful blacklight inks.
On many German locomotives the controlpanel labels were printed with blacklight paint and a blacklight source was provided in the cab. This left the driver with full night-vision while still enableing him to distingish between the different switches and levers to operate his locomotive.
Blacklight paints are sometimes used in the scenery of amusement park
Amusement park
thumb|Cinderella Castle in [[Magic Kingdom]], [[Disney World]]Amusement and theme parks are terms for a group of entertainment attractions and rides and other events in a location for the enjoyment of large numbers of people...
dark ride
Dark ride
A dark ride or ghost train is an indoor amusement ride where riders in guided vehicles travel through specially lit scenes that typically contain animation, sound, music, and special effects....
s: a blacklight illuminates the vivid colors of the scenery, while the vehicle and other passengers remain dimly lit or barely visible. This can enhance the effect of being in a fantasy world
Fantasy world
A fantasy world is a fictional universe used in fantasy novels and games. Typical worlds involve magic or magical abilities and often, but not always, either a medieval or futuristic theme...
.
Blacklight paints may be fluorescent or, more rarely, phosphorescent
Phosphorescence
Phosphorescence is a specific type of photoluminescence related to fluorescence. Unlike fluorescence, a phosphorescent material does not immediately re-emit the radiation it absorbs. The slower time scales of the re-emission are associated with "forbidden" energy state transitions in quantum...
, containing a phosphor
Phosphor
A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness , and fluorescent materials, where the emission decay takes place over tens of nanoseconds...
that continues to glow for a time after the blacklight has been removed.
Some clothes worn in survival and rough weather situations sometimes have dayglo strips and patches for conspicuity.
In nature
Some natural pigments (for example, on some scorpionScorpion
Scorpions are predatory arthropod animals of the order Scorpiones within the class Arachnida. They have eight legs and are easily recognized by the pair of grasping claws and the narrow, segmented tail, often carried in a characteristic forward curve over the back, ending with a venomous stinger...
s) shine in visible light if illuminated with ultraviolet light.