Feature/Review: 3 Thing You Didn’t Know About The Panerai Luminor

It’s been 70 years since the Panerai Luminor first came to be, and as this new Luminor Luna Rossa Regatta, with its split-second regatta timer, in-house calibre P.9100/R, dial made from the sail of the Luna Rossa racing yacht and lightweight carbotech case demonstrates, it’s come a long way. But there’s a lot more to this piece of Italian eye candy than you might first think, so with that being said, here are three things about the Panerai Luminor that you probably didn’t know.

Luminor Is The Name Of The Paint On The Dial

New or old, it’s the Panerai Luminor, right? Panerai being the name of the company that sells them and Luminor being the name of the model? Well, not quite. Luminor was a name that already existed for a whole year before the watch named after it was released in 1950 for the Italian Navy, and it had nothing to do with the watch.

To understand why that is, we need to go back a few decades to 1916, to a patent filed in France on the 23rd of March. This was not a patent for a watch or a complication or anything like that—it was a patent for some paint. There were several special things about this paint, the first being that it adhered like the proverbial even when submerged in water. This was important, because Panerai, then a jeweller selling Swiss watches, had an idea.

The importance of diving to the military was quickly becoming a lucrative business, and so the Panerai family looked to invest in it. There were all sorts of things a military diver needed to do their job underwater, such as depth gauges, compasses, torches—but there was a problem. It can get very dark underwater—especially at night, when military divers would be most active—and so a way to see these devices underwater was needed.

Panerai was founded in 1860 by Giovanni Panerai

That brings me on to the second thing this paint could do—it glowed in the dark. By containing radium, a highly radioactive substance, the paint was energised and would glow without any power source needed. It was the answer, allowing divers to read even the finest text on their instruments deep underwater. The paint, named after that key ingredient, was called Radiomir.

But there was a problem. Radium, as it turned out, emitted incredibly harmful gamma rays, capable of destroying human cells and causing deadly necrosis. This was at the forefront of scientific discovery, and companies all over the world were using this new wonder material in anything and everything—including, ironically, health products. Even radium’s discoverer herself, Marie Curie, died from radiation exposure. Something needed to be done.

And so, in 1949, a new patent was filed by Panerai. Same glow, same adhesive properties—only this time fuelled by the much less harmful tritium, whose beta particles were far, far weaker. This new paint was given a new name, one that shed the connotations of the old. It was called Luminor.

The Luminor Watch Is An Evolution Of A Rolex

You might wonder why the Panerai Luminor isn’t round, and it’s a sensible thing to ponder. This, what’s known as a cushion case, is rather decorative and unnecessary for what is otherwise simply a piece of equipment. Most dive watches of the era were housed in simple, round cases, protrusions sprouting where needed to hold the strap and protect the crown and what have you—and nothing more.

Yet the Luminor has an almost Art Deco vibe about its sculptural case that really serves no purpose to the diver using it. I know the Italians are a stylish people, but I think they draw the line at making the military look dapper too. No, there’s another reason why the Panerai Luminor looks as it does, and it’s one of a more coincidental nature.

Remember when I said that Panerai was first and foremost a jeweller? As in one that sells watches, repairs a few on the side? The little Italian shop was not equipped to be in the business of actually making watches, certainly not in the number requested by the Italian Navy, and so it was to an external contractor that Panerai sought to find a watch on to which to scribe its patented glowing paint.

Panerai has remained in Florence, Italy since it's founding

There was no such luck with big guns like Omega and Longines. Instead, Panerai needed to find a company that was young and upcoming, and wouldn’t cost a fortune. Believe or not, that company was Rolex, whose water-resistant Oyster case looked to be just the ticket for Panerai’s watch. By the time Radiomir paint was patented, Rolex was barely a decade old. It was a company that shared a like mind with Panerai, founded in a jeweller’s, wanting to be something more.

And so a partnership was forged. Rolex wanted to build relationships across the board as part of its plan to be the watchmaker of industry, eventually exploring other such deals with airline Pan Am and nuclear research facility CERN, but it was early days, and for now, this Italian jeweller with ties to the Navy was as good as it was going to get.

One problem, however—Rolex didn’t actually make watches. The company simply commissioned cases, bracelets, dials, movements—you name it—in a configuration of its choosing, and so that meant that building Panerai’s watch would need to be achieved using parts they already had. The size demanded a large case, and so one from a pocket watch was chosen. Funnily enough, this was in the period of Art Deco, so the case chosen was a cushion shape. Wire lugs were soldered on as a make-do, and Panerai supplied the paint for the dial. And thus, the Luminor’s cushion-shaped case was born.

The Locking Crown Guard Stopped The Watch Breaking

Between the Radiomir and the Luminor—the watches, not the paint—lie a few concrete differences. It’s clearly an exercise in education, as much for Rolex—who, by the time the Luminor came out, was thinking about a dive watch of its own—as it was for Panerai, learning from its mistakes and improving upon the original.

As we’ve seen, the Radiomir was very much a parts-bin special, the best Rolex could achieve given what it had available to it, and it served well all things considered. But for round two, for the new Luminor paint, there were significant changes to be introduced that would make it even better.

The lugs are an obvious move. Given that the Radiomir’s were simply pieces of wire soldered onto a pocket watch case—I mean, I’ll say it, it was a bodge—and not screwed in like they are today, there was a lot of room for improvement. It was actually in the 1940s that the lugs became a solid integrated item, part of a mid-life refresh before the bigger update. The wire lugs may have been absolutely fine, but then you don’t really need to be an engineer to guess that they were probably the weak point in the whole package.

Panerai was acquired by the Richemont S.A. group in 1997

The second big change was the crown, or rather, the mechanism that held it in place. When used over and over, there’s a risk of stripping the threads on a screw-down crown, but without them the watch just wouldn’t be watertight. You might wonder why the screw down crown became a prominent fixture of pretty much all dive watches from the 50s onwards if it’s such a concern, and that was because of one simple, yet significant update: automatic movements.

Even though Rolex debuted its self-winding Perpetual movement in 1931, Panerai watches still housed a manually wound engine. This is not unusual—for high-stakes military application, cutting edge technology is often eschewed for the tried-and-tested option, something with a predictable service life and more easily maintained in the field.

Nevertheless, having to wind the movement every day was causing a problem. Crowns were being damaged, threads stripped, watches flooded and destroyed. The solution, it seemed was one that required a step back to go forwards. Instead of screwing the crown down to clamp the seal tight shut, a lever was bridged over the top to clamp it in place instead, with the added benefit of protecting the crown from knocks. It wasn’t subtle and it certainly wasn’t high-tech, but hey—it got the job done.

There’s something to be said about the evolution of a design that relies on budget, technology constraints, user error and a punishing life to find its form. Building something without restraint, from the ground up, often loses a sense of character. Think of the Porsche 911, a car that’s built to a compromise, that’s grown to accommodate it and become one of the most iconic pieces of automotive engineering in the world because of it. The Panerai Luminor is just the same, hewn from concession to create a lasting impression that could have never come to be any other way.

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