In the late 90s, tritium was in fact banned. And tritium-based substances ceased to be used by Omega in , and Rolex in As with the Radiomir, the Luminor too originally had radioactive lume, as was the case with this early Luminor watch from This modern-day Luminor retains the now-iconic crown protector and cushion-shaped case.
It features Panerai's most recognisable silhouette, and thankfully isn't radioactive anymore. Today, tritium is used again by a few manufacturers, however, not as a paint or paste.
A radioactive form of hydrogen, tritium gas is filled into borosilicate glass capsules, internally coated with a layer of phosphor. As the gas undergoes beta decay, the electrons released cause the phosphor to glow.
The gas is still radioactive, but is apparently less of a hazard than tritium-based paints, because of being in tubes. Luminox and Ball are among the watch manufacturers known to use tritium gas tubes quite prominently on their dials. The advantage is that unlike Super-LumiNova, which will most certainly stop glowing after a few hours of exposure to light, tritium tubes will continue to luminesce, even if the glow becomes dull over the years, and lead to them needing replacement.
Ball watches use tritium for their luminescence, but only in the form of tritium gas tubes, which minimises the risk of exposure. The tubes are seen here as hour markers and on the hands. Even Luminox are among the manufacturers that are known to use tritium gas tubes for luminescent parts today. Here too, it's the hour markers and hands that feature the tubes. Finally after decades of taking chances with substances that were literally radioactive, there seemed to be some hope that a watch could glow and actually be safe even—imagine that!
Strontium aluminate used in LumiNova—along with europium, a safe chemical that aids its phosphorescence—proved to be far more effective than its regressive predecessor, being able to glow several times brighter and longer than zinc sulphide, without causing any harm. The only disadvantage was that the perpetual glow was gone along with the radioactive lumes of the past, but who needs the baggage that came with them anyway! Over time, there have been customisations to this super pigment by various brands, as they are known to do, creating proprietary versions of existing materials to enhance performance and durability.
While Rolex began to use Super-LumiNova in , they introduced their proprietary version of the pigment, called Chromalight in , with the launch of the Oyster Perpetual Sea-Dweller Deepsea.
Eventually the maison began to use Chromalight in their other professional watches as well. It's seen here on the dial of a Seiko Prospex. LumiBrite forms a part of the dial on this Prospex chronograph as well. It is rather prominently featured on the large hour markers and hands.
A blue glow is, however, not restricted to Chromalight. In fact, Super-LumiNova itself is available in different hues, including blue, but is probably not as bright as Chromalight. Green is generally the preferred choice by many watchmakers, owing to the human eye being most sensitive to green emission when shifting from brightness—or photopic vision—into darkness. However, blue is more impactful on the eye in the case of scotopic vision—or vision in extreme darkness, when there is higher sensitivity, but a minimal perception of colour.
Sometimes, though, the various hues of Super-LumiNova are used simply for aesthetic purposes. Aesthetic uses of Super-LumiNova extend even to the volume of the pigment and its combination with other materials, for larger impact, enhanced luminosity and dimensionality even. Aesthetic uses of Super-LumiNova often extend even to the volume of the pigment used for larger impact, enhanced luminosity and dimensionality even, as seen in this Autavia in bronze.
Licensing requirements for the use of radioactive materials in consumer products are based on the quantity and radioactivity of the materials. Generally, the NRC does not regulate antiques, but there are a few exceptions depending on the origin of the radiation source and the source strength.
The EPA's Superfund program cleans up badly contaminated sites. Contamination at some of these sites includes antiques containing radioactive materials. For example, one cleanup site contained more than one million World War II aircraft gauges with radium dials. Many of these radioactive sources were leaking. Radionuclide Basics: Radium This webpage contains basic information about radium, a radioactive element found in some antiques. Superfund: U. Radium Corporation-site. Heavy-element chemistry at Los Alamos This webpage discusses why glass objects containing uranium glow green when exposed to UV radiation from a black light.
Fiestaware This webpage, created by Oak Ridge National Laboratory, discusses the ways depleted uranium was used to create Fiestaware glazes. The HPS is a group of scientists that research and make recommendations about ionizing and non-ionizing radiation topics.
They also produce informational reports, fact sheets, and websites to help people better understand radiation. The Society is established in the United States as an independent nonprofit scientific organization, and is not affiliated with any government, industrial organization or private entity.
Skip to main content. Contact Us. Radioactivity in Antiques. Back then, the luminous paint applied to the hands and indices on the dials contained radium, which was obviously found to be harmful to the wearer later on and in part prompted adoption of tritium compounds in luminous paint. My question is: What isotope of radium was typically used and what is its half-life? I see these watches in antique shops, jewelry stores, and online, and I wonder if the radium is still bombarding everything within line-of-sight with gamma radiation, or if it would have completely decayed by now, plus years later.
If these watches are still active sources, that implies to me that they would be regulated by the Nuclear Regulatory Commission NRC. Since I don't see any evidence of such regulation, I might conclude that they must not be a source of gamma radiation any longer. I just don't know; the majority of people wouldn't give it a thought, but as an engineer I can't dismiss the possibility so easily.
Should these old watches be handled in a special way, or should one just avoid them altogether? Can watches that do not have radium luminous paint but are stored in the same location as radium-containing watches become radioactive themselves; i. You have raised thoughtful questions no doubt arising from your engineering interest in how things work. The bottom line for your concerns is that no special handling is required for radium-dial watches, except that you should not open them or attempt to remove the radium paint, which could result in radium ingestion.
You may be interested in the response to a similar question, Question I would like to respond to your questions by providing some historical information on how radium came to be used for illumination. See the Oak Ridge Associated Universities website for a good discussion on such uses of radium.
Though still radioactive, the gas poses less risk than tritium paints by way of its being encapsuled. However, with a half-life of just 12 years, after about 24 years only a quarter of the radioactive material is left; thus, tritium gas tubes glow dull enough to require replacement. Pictured above: The Timex Weekender. Electroluminescence is the production of light as a result of an electrical current passing through a phosphor. In a watch, a glass or plastic panel is coated with an electric conductor and a phosphor, then is mounted behind the dial.
At the press of a button, an electric current is delivered, causing the phosphor to react, acting as a backlight. The company patented the technology in , making Timex one of the few producers of analog watches with this type of lume, though other affordable quartz timepieces from Bertucci and Casio have used it as well.
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