Super-LumiNova X1 is a photoluminescent formulation based on strontium aluminate, free from radium and tritium. It is not the entry-level version of the line: it is the highest-performing grade of the Super-LumiNova system developed by RC Tritec, the Swiss company that owns the brand. This distinction matters, because manufacturers sometimes use the X1 suffix imprecisely in their datasheets, and it's always worth checking what they actually mean.
The operating principle is photoluminescence: the pigment absorbs photons during exposure to light and releases them gradually in the dark. It does not emit autonomously and requires no radioactive source. The decay of luminosity follows an exponential curve: maximum intensity is reached within the first few minutes, then progressively decreases over hours. X1 distinguishes itself from previous formulations through greater initial brightness and longer persistence for the same applied thickness.
The emission color is not unique. The standard version emits in green-white, the most readable to the human eye in dark conditions. However, certified color variants exist: blue, intense green, orange. Some manufacturers — Zenith on the Defy Extreme Diver is a documented case — use three different pigments on the same dial to encode distinct functions through the emission color. Ming on several models, including the 37.06 and 29.01, works with the blue variant, applied both to the hands and to the channels laser-cut into the chapter ring. Laser engraving is relevant: it creates a precise housing that protects the pigment and ensures uniform distribution.
Application can occur in paste form, by brush or screen printing, or by infusion into composite materials. The case of HyCeram ceramic used by Ming in the 29.01 Midnight is technically interesting: the pigment is incorporated into the ceramic matrix before sintering, which guarantees mechanical solidity. Under normal conditions, paste application is more common and sufficient for the vast majority of uses.
Insufficient coating thickness reduces both initial brightness and duration. This is why two watches declaring the same material can perform differently in the dark: the pigment specification is only one factor; the application method and thickness make up the rest.