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November 1917 ad for an Ingersoll "Radiolite" watch, one of the first watches mass marketed in the USA featuring a radium-illuminated dial. Radium was discovered by Marie and Pierre Curie in 1898 [1] and was soon combined with paint to make luminescent paint, which was applied to clocks, airplane instruments, and the like, to be able to read them in the dark.
Radium paint was widely used for 40 years on the faces of watches, compasses, and aircraft instruments, so they could be read in the dark. Radium is a radiological hazard, emitting gamma rays that can penetrate a glass watch dial and into human tissue. During the 1920s and 1930s, the harmful effects of this paint became increasingly clear.
The first use of radioluminescence was in luminous paint containing radium, a natural radioisotope. Beginning in 1908, luminous paint containing a mixture of radium and copper-doped zinc sulfide was used to paint watch faces and instrument dials, giving a greenish glow.
These particles excite the phosphor, causing it to emit a low, steady glow. Tritium is not the only material that can be used for self-powered lighting. Radium was used to make self-luminous paint from the early 20th century to about 1970. Promethium briefly replaced radium as a radiation source. Tritium is the only radiation source used in ...
The following year, a new facility at the Bloomsburg plant opened for the manufacturing of "tritiated metal foils and tritium activated self-luminous light tubes," [9] and the company switched focus to the manufacture of glow-in-the-dark exit and aircraft signs using tritium. Starting in 1979, the company underwent an extensive reorganization.
Stars made of glow-in-the-dark plastic are placed on walls, ceilings, or hanging from strings make a room look like the night sky. [29] Other objects like figurines, cups, posters, [30] lamp fixtures, toys [31] and bracelet beads may also glow. [32] Using blacklights makes these things glow brightly, common at raves, bedrooms, theme parks, and ...
Phosphorescent pigments performance, in visible light, in dark, after 4 minutes in dark - zinc sulfide (left) and strontium aluminate (right) based materials Super-LumiNova is a brand name under which strontium aluminate –based non- radioactive and nontoxic photoluminescent or afterglow pigments for illuminating markings on watch dials ...
In many cases luminous dials were implemented with non-radioactive fluorescent materials excited by light; such devices glow in the dark after exposure to light, but the glow fades. [14] Where long-lasting self-luminosity in darkness was required, safer radioactive promethium -147 (half-life 2.6 years) or tritium (half-life 12 years) paint was ...