Rolex dial quality and night glow painting (lume) material have undergone significant changes in the last half century. Rolex dials today no longer oxidate, patina, or flake because of the extremely durable paint materials applied to the dials. However, only time will tell how the dials will react to decades of owner use. In this section we will examine some of the common dials over the years, their materials, and what the designation at the 6 o’clock position means.
This below is a very early issue 7021/0 blue snowflake by Rolex Tudor, back in an era when Rolex still supplied the case components for Tudor. At the 6 o’clock position, the T Swiss T designation indicates the dial contains tritium, a radioactive material. The tritium is applied as the hour markers, and on the three hands. Tritium glows for a finite period of time, and unless a Rolex tritium dial has been relumed, it will not glow today.
Here below in the picture we have a Rolex T Swiss Made T dial, which just again indicates that the dial has tritium on it. The maximum amount of tritium on a dial like this is limited to 25 millicurie.
This U serial Rolex Explorer II REF 16570 below is also a tritium dial Rolex, but note the 6 o’clock designation has changed to “Swiss – T < 25." This dial design still uses tritium as the lume material for the hour markers and the hands, but the maximum amount of tritium on the dial is less than 25 millicurie as indicated by the < 25. In this particular timepiece the lume has remained white over the years, though it is very common to see eggshell yellow patina on tritium.
In the dial below we have a simple “Swiss” designation at the 6 o’clock. This is the earliest designation for a modern luminova dial, and the Rolex Swiss dial contains no more radioactive tritium. Instead the dial uses luminova, a non radioactive material invented in 1993 by Nemoto & Co., Ltd. of Japan. Luminova will absorb light, both natural and artificial, and use that light to provide night lume for hours. The lume color is green.
The Rolex below is another REF 16570 Explorer II, same model as the tritium model above, except with luminova. However this time it has a Rolex “Swiss Made” Dial at the 6 o’clock designation. This indicates a continuation of the luminova dial and replaced the Rolex “Swiss” dial seen previously. The lume color is again green. It is important to note that very old Rolex watches made prior to the 1960′s also had Swiss and Swiss Made designations. Those timepieces had radium as the lume source, and radium is much more damaging to health compared to the also radioactive tritium.
Finally, below we have a modern day year 2013 Rolex REF 214270 39mm Explorer. It also sports a Swiss Made dial with the “Swiss Made” at the 6 o’clock. However the lume material has been upgraded once again by Rolex. This time the material is called chromalight, and it glows blue instead of green like luminova. We have found this new material to be harder to charge (we use the sun or a lamp to charge the lume to see how long it lasts), however it glows noticeably longer than the green luminova it replaced. The new material had no impact on the 6 o’clock designation as it stays “Swiss Made” for Rolex models today.
