This is the story of how the application of luminescence on the first military dials in the early 1900s proved to be a serious health problem and the measures that today are summarized in the inscription T-swiss<25 were then adopted.
Let's take a step back in time…
At the end of the 1800s, exactly in 1898, radium was discovered and in 1902 isolated as a pure element. It was introduced in the most common uses as a revolutionary element for teeth whitening, miraculous for the treatment of tumors, in make-up and beauty products. Its unique property was its luminescence and the heat of its salts.
Marie and Pierre Curie, the scientists who discovered radium in 1898
During World War I servicemen complained about the poor shock resistance of their watches and how they could not read the time in the dark during nights in the trenches.
For this reason, dial manufacturers began to use radium mixed with glue and a small amount of zinc sulphide, thus obtaining a luminescent paint to be applied to the hands and indexes. This is how the first watches with "luminous" dials and hands were born, which helped the soldiers during the endless nights in the trenches to consult their measuring instruments but without being noticed by the enemy.
Example of a luminescent dial
The amount of radioactive material present on the dials was not such as to harm the wearer, but on the contrary, it was the beginning of the end for those who painted the dials.
In 1917 in the United States and Canada, thousands of women were hired to apply radium-based luminescent paint on dials;
the danger of radium was not known, on the contrary, it was considered a miraculous element, given its wide use in the main daily uses and in medicine.
A bottle of RADITHOR, a medicine used in the 1920s as a cure for various pathologies.
The girls were asked by the production supervisors to thin the tip of the brushes during their use, to achieve maximum precision in outlining the numbers on the dials; the brush was inserted into the mouth and turned as it was extracted between the lips to ensure that the bristles were always compact. This caused the luminous substance to come into contact with the lips and tongue and possibly be ingested.
The "Radium Girls" at work
The serious thing is that it was never questioned whether this was safe for the painters, regardless of whether the scientists and superiors used safety measures: lead shields, special gloves to avoid exposure on themselves. The scientists and the owners of the firm were aware of the potential risks.
Sometimes the girls used to paint their nails and lips with luminescent paste, their dancing evenings in the village with their boyfriends took on a completely different "light", unaware of what would happen in a few years.
This is how they began to suffer from radiation sickness. The most common symptom of the disease, due to their work in the factories, was necrosis and fracture of the jaw. Teeth began to fall out, there was severe jaw swelling, severe distress and weakness. Dentists and physicians in Orange, New Jersey began to notice an increase in the amount of disease and damage found in the jawbones of local young men and women. The bond between them soon became apparent: they had all worked at the US Radium factory.
And Rolex?..how did he behave in this regard?..
Rolexes from the 1950s still used radium for luminescence. The models with luminescence were predominantly Submariner, Turn-O-Graph, Explorer and GMT Master.
Submariner Big Crown on radium, photo rolexpassionmarket.com
The Atomic Energy Commission of the late 1950s set limits in terms of radioactivity, also forcing watch manufacturers to adapt to the new laws.
Rolex continued to use radium, but did so by applying a less aggressive paint, thus lowering the radioactive content of its products.
To indicate this reduction of radium, the models of the crowned house had an indication on the dial, a dot under the six o'clock index, collectors called these references "ESCALMATION POINT".
Gilt ROLEX Submariner Ref. 5512 photo rolexpassionmarket.com
In 1962 there was a new lowering of these thresholds, the control bodies fixed the value of the presence of radioactive materials at a maximum of 25 mCi (millicurie).
From 1963 to 1964 Rolex will produce dials, very rare today, with a small line under the writing, this indicated the new material used by the manufacturer to make the dials luminescent, TRITIUM, an isotope of hydrogen , less luminous and much less radioactive than radium.
Rolex Submariner 5513 from 1963 called "UNDERLINE"
From 1964 to 1967, the writing Swiss - T <25 appears on Rolex watches, which refers unequivocally to the presence of tritium with a radioactivity level lower than the 25 mCi required by law.
Rolex Submariner 5513 from 1964 with SWISS - T<25 inscription
In 1993, a pigment based on aluminate and strontium was invented, patented in 1995 under the name of Luminova . This made it possible to obtain non-radioactive luminescence. Rolex began to use this new component starting from 1998, so only the Swiss writing appeared on the dials, then replaced with Swiss Made starting from 2000, given the use of Super Luminova, a new compound more powerful than the traditional Luminova.
From 2009 Rolex begins to use Chromalight, a material of its own invention, the distinctive feature of the color of luminescence, blue.
Check out the graphics inspired by this article! EXCLAMATION POINT
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