By Jovan Krstevski
The Panerai Luminor was only available to the military forces but in 1993, the Luminor and the Luminor Marina were made public to the joy of the anxious crowd. The Luminor model achieved staggering international success partly because of its design that’s linked to the exclusive original. Join us as we step back in time and see how this iconic watch came to life.
Panerai Luminor’s creator is Giovanni Panerai who opened his shop in Florence in 1860. He became an authorized dealer of many popular Swiss brands like Rolex, Vacheron Constantin and Patek Philippe. Panerai started supplying the Royal Italian Navy in the early 20th century with high precision instruments.
On 23 March 1916, a patent was granted to the Radiomir which is a radium-based powder with luminous properties. This became instrumental for the creation of the Radiomir watch whose prototype was created in 1936. This was due to the order of the Royal Italian Navy who wanted a rugged watch that can survive extreme conditions commonly met by the frogman commandos of the First Submarine Group Command. The Radiomir met the requirements particularly having excellent readability even under water thanks to the luminous Radiomir. This watch was radioactive but at that time the dangers of exposure to radiation wasn’t clearly understood.
The Rolex Calibre 316 movement
The Radiomir’s design was legendary, sporting a 47 mm cushion-shaped case with large screw down “onion” crown. It has wire lugs welded to the case and a long water-resistant strap that can also be used over a diving suit. It was powered by a hand-wound movement made by Rolex, the Calibre 618. The Radiomir has seen various models like the Radiomir reference 2553 with barred/dotted hour indicators and Radiomir reference 3646 with Roman and Arabic numerals.
Radiomir reference 2553 with barred/dotted hour indicators – Photo: John Goldberger
Radiomir reference 3646 with Roman and Arabic numerals – Photo: John Goldberger
After successful and secretive tests, in 1938 Panerai started supplying the Royal Italian Navy with reference 3646 being the first lot of watches supplied.
Due to the Royal Navy’s ongoing requirements, the watch kept improving where in 1940, larger lugs made from the same block of steel as the case replaced the soldered wire lugs – this resulted to better water resistance seen on reference 6152–1.
A “sandwich” dial was developed where 2 overlapping plates work together for better legibility – the lower part contains the radium compound covered by a thin transparent Perspex layer while the upper part with perforated indices and numerals makes the radium paint more luminescent. Some modifications also improved the dial by adopting four Arabic numerals at the cardinal points integrated by a series of barred indices.
When Rolex’s role as supplier ended, Panerai equipped their watches with Angelus 240 movement sporting superior power reserve of 8 days compared to Rolex Calibre 618’s 41 hours. This was instrumental for the Panerai watches to guarantee water tightness over time since it reduced the number of times required to wind the watch.
The Luminor finally replaces the Radiomir in 1949. This self-luminous substance is more luminous and safer than the radium-based Radiomir. Patent was granted in 11 January 1949 for the new tritium (hydrogen isotope) based compound officially bearing the “Luminor” trademark.
The shift from Radiomir to Luminor was completed in the Fifties. The signature crown-protecting device was also patented in Italy in 1955 and a year later in the USA. This “Tight Seal Device” was filed by Giuseppe and Maria Giuseppe Panerai who were also listed as the inventors. This tech remarkably improved the Luminor’s water resistance to 200 meters which at the time was unbeatable.
Reference 6152-1 made in 1955 with the patented crown protection system, dark brown “sandwich'”dial and Radiomir Panerai signature – Photo: John Goldberger
Reference 6152-1 made in 1955 the signature on the black dial is ‘Marina Militare’ – Photo: John Goldberger
Reference 6152-1, manufactured in 1956, with ‘Marina Militare’ and ‘Luminor Panerai’ signature and small seconds sub dial at 9 o’clock – Photo: John Goldberger
The watches with tight seal devices were identified as reference 6152–1 and were equipped with either the Angelus 240 or the Rolex Calibre 618. Interestingly the prototypes still used Radiomir on the dial but the production watches included designations as “Marina Militare” or “Luminor.”
The P.2002 in-house movement
Panerai also developed its in-house movement, the P.2002. Its 8-day power reserve is a tribute to the historic movement adopted by Panerai in the 1940s.
Panerai 1950 47 mm PAM 372
Newer models like the Panerai 1950 47 mm PAM 372 sports newer Calibre P.3000 movement. Its matte black dial with “sandwich” construction also makes the most historical Luminor model to date.
Panerai Luminor 1950 3 Days Chrono Flyback Ceramica
Today, the Luminor’s success is continuously made possible by the Officine Panerai offering full range of models with advanced functions from the GMT, full chronographs to tourbillons. For more info, please visit panerai.com