Insight: Chasing Rainbows! An In-Depth Look At The Zenith El Primero Rainbow
Let's Find That Pot Of Gold

As a Zenith enthusiast I would like to contribute to the knowledge about the Zenith El Primero Rainbow. A watch developed in the nineties, not widely known, yet no less interesting. In this article I will give you an overview of the key facts and figures concerning this line of flavourful sports watches developed by Zenith. I will start from its very inception and take you all the way to the end of the Rainbow. Let’s see if a pot of gold awaits..

First of all, why the name Rainbow? For that we have to return to 1934 when the America’s Cup sailing competition was held. As an aside, the America’s Cup sailing competition was formerly called the “Auld Mug”, making it the oldest international sports trophy in the world.

During the 1934 race, the New York Yacht Club was challenged by the British Royal Yacht Squadron. The British were the all-time favourite with their Endeavor yacht which was recognised as the fastest yacht at the time and with which they immediately took home the first 2 series that year. The Americans appeared at the start with the Rainbow, a single mast racing yacht built in 1930. The tide turned for the Americans when the British made some wrong decisions in which the Rainbow, as the underdog, took the next 4 heats and with it the overall victory.

I cannot confirm whether that underdog position was decisive for the watch’s name choice, but the fact is that Zenith had been supplying their famous El Primero caliberCaliber The caliber ('movement') is the heart and engine of a watch. It consists of a number of interconnected components that work together. Energy is transmitted through the gear train, to the escapement mechanism. The escapement mechanism releases this energy in a controlled manner. This drives the gear train, which ultimately rotates the hands of the watch and keeps time. [More Info] to Rolex since 1988, who, after modifications, spooned it into their Daytona for the following 12 years.

The Zenith EP Rainbow watch was shown at Basel show 1992 and became available to the public at the end of 1992. It was intended as a sporty waterproof watch with a 40mm case, 20mm lugs, fitted with an anti-reflective sapphire crystal, screw-down crowns and powered by the famous El Primero caliber. Furthermore, it was equipped with a fixed bezel that rotated unidirectional or in both directions, possibly featuring a tachymeterTachymeter A tachymeter is a feature found on some chronograph watches, it is a scale that is usually printed on the bezel, sometimes on the dial. It allows the wearer to measure the speed of an object over a known distance by timing the object's movement with the chronograph's second hand. The wearer can read the speed of the object on the tachymeter scale. [Learn More] and / or telemeter. This depended on whether one preferred a diving watch or rather a pilot’s watch

The models from the first 3 years all have the text “MODELE DEP” (registered model) engraved on the back. These models are also equipped with Luminova and only later models got tritium. This is one of the few watches that was available so early and originally with Luminova. Tritium was banned around 1999, coinciding with the final production of the Rainbow.

The models after 1996 also have a tritium pearl at 12 o’clock, probably to meet the diving watch standard introduced that year. A typical reference number might look something like “01.362.400”. The first two numbers of the reference refer to the material of the case and strap. Here’s some non-limited overview:

• 01: steel case with leather strap
• 02: steel case with steel bracelet
• 30: 18k gold case with leather strap
• 41: steel case with 18 kt gold bezel and leather strap
• 53: steel case with 18 kt gold bezel and steel bracelet
• 60: 18 kt gold case and bracelet

The middle part of the reference number contains 3 digits and refers to the specific version, like with or without telemeter. The last number in this 3-digit series refers to the color of the dial. However, probably because of production technical reasons, you will not find this on the watch itself, only in the catalog. In that position there is always a 0 on the back of the watch, while in the catalog for example a 3 (white) or a 2 (black) will be printed. Finally the last part of the reference, also containing 3 digits refers to the movement used.

Don’t be surprised to see a watch that reads 01/02.470.405 engraved on the case back.  It looks like Zenith used this logic near the end of the series to cover models either with leather strap or with steel bracelet (or both same time).

All in all, not that many Rainbows have been produced. The most popular references in steel may have reached production quantities of 1,600 units. The more exclusive variants, such as the Mango, only a few hundred. There are reference books that speak of 470 copies, but it is not clear whether this only refers to the EP Rainbow or if the Mango variant of the Elite Rainbow is also included.

That Elite Rainbow was added in 1995 and had no chronometerChronometer A chronometer watch movement is a high-precision movement that has been certified by an official organization, such as the Swiss Official Chronometer Testing Institute (COSC) or other similar bodies, as meeting certain standards of accuracy and performance. These standards include requirements for the rate of the watch, its resistance to temperature and other environmental factors, and its power reserve. Chronometer watches are tested for several days, in different positions, and at different temperatures to ensure their precision. [Learn More] but only time and date function. This diving watch was originally equipped with an ETA 2892 until Zenith reverted to this decision and switched to their own Elite automatic caliber. Those first ETA divers can be recognised by the date window at 3 o’clock and obviously the word Elite was still missing on the dial.

But this article is not about the Elite Rainbow, I’ll limit myself here to the El Primero Rainbow. The EP Rainbow was immediately warmly received by the press and public in 1993. In 1994 the watch won the title “Best ChronographChronograph A chronograph complication is a feature in a watch that allows the wearer to measure elapsed time in addition to telling the time. It works by having a separate set of gears and levers, called the chronograph mechanism, which is activated by pressing a button or a pusher. The chronograph mechanism starts and stops the chronograph's second hand, which is usually located on the watch's dial, separate from the regular watch hands. The elapsed time is usually displayed on a sub-dial or a register on the watch's dial. [Learn More]” in Germany, beating the Omega Speedmaster and the Rolex Daytona, among others. The original EP Rainbow was available in steel with white, black and at the end of production also with an ocher yellow dial. The latter was immediately given the nickname Mango. It is the most exclusive steel version and therefore a very popular object for collectors.

In two-tone version there was also a dark blue dial available. The 18k gold version was available with a creamy ivory or black dial. There are also some versions known with a bezel set with 58 diamonds, both in steel as in gold version. As far as I know there have only been yellow gold versions, no white or pink gold. At the Basel show in 1997, another chapter was written when the FlybackFlyback A flyback function on a chronograph watch, allows the user to reset the chronograph back to zero and start timing again with a single button press (no need to first stop the watch). [Learn More] version of the EP Rainbow was presented. The indirect reason for the Flyback goes back to 1995 and is a story in itself.

In May of that year, the French Air Force opened a tender for the delivery of a suitable pilot’s watch. Story goes that it was the army’s intention to yearly order 1000 watches and this for 4 consecutive years.  Zenith took part in the tender and, in order to meet the specific requirements of the Air Force, had to adapt the existing caliber, thus modifying the EP400 caliber into the EP405 caliber. Most drastic adjustment was the Flyback function, meaning you did not have to press the start / stop button at 2 o’clock to start a new time measurement. You just pressed the reset button at 4 o’clock and a new timing started automatically from 0 seconds (12 o’clock position).

Further changes for military purposes included the replacement of the screw-down upper and lower crowns with normal push buttons, a bezel with larger and irregular serrations, a bright red second hand, a red twenty-minute index on the bezel, a fully matt satin finish on both case and strap, the use of aeronautical sector colours for the minute dial at 3 o’clock and a back with no image of the Rainbow ship, instead featuring a Zenith shield logo.

All of the above features had a functional reason including better reading under all type of circumstances, stealth appearance, navigation via radio or enhanced operation during flight.  This made the Rainbow probably the last mechanical watch of any brand that was specifically developed or modified for military purposes.  A few months later, Zenith delivered a box containing the first 6 units to the Air Force to start the initial testing program.Unfortunately, new elections were called in France in November 1995. The military budget tap was turned off and the entire tender ended up in the trashcan.

Zenith then decided not to instantly write off the development work and instead brought the Flyback variant to the Basel show in 1997. Not only in the newly developed functional and colourful military specification but also in a more discreet civilian version with a black & white scheme.

The military version by the way does not have a Flyback inscription on the dial, the black & white version does. Next year we will be 2022 and 30 some years later.  Dear Zenith, how about a Rainbow revival edition? In Mango colour please? 

If you want to find out more about Zenith El Primero Rainbow watches please also check following publications:

• Zenith: Swiss Watch Manufacturer, by Manfred Rössler, ISBN 9788862080699
• Zenith: La saga d’une manufacture horlogère étoilée, by Joel Duval, ISBN 2226259104
• Author Unknown: Informative post on WUS Forum right here