What it is
Super-LumiNova is a strontium aluminate photo-luminescent compound, manufactured by Swiss firm RC Tritec since the early 1990s. It contains no radioactive elements; instead it works by charging from any light source and slowly re-releasing photons over several hours. The compound is mixed with binder paint and applied to hands, indices, and bezels. Modern Super-LumiNova grades (LumiNova X1, Grade A, BGW9 'Old Radium' variants) achieve initial brightness comparable to historical tritium without the radiation.
How it differs from old lume
Radium (1916-1960s): the original luminous compound. Highly radioactive (radium-226). Workers painting dials died from radiation poisoning ('Radium Girls' scandal). Banned in watch use post-1960s. Tritium (1960s-1990s): less-radioactive hydrogen isotope, painted onto hands as a tritium-phosphor mix. Self-luminous for ~12 years before decay. Replaced by Super-LumiNova starting 1995. Vintage tritium-lume watches now have weak-to-no glow because the tritium has decayed.
How it differs from tritium tubes
Tritium gas tubes (Marathon, Ball, Luminox, some Sinn): tiny sealed glass capsules filled with tritium gas; the gas glows continuously without external charging for ~12-25 years. Self-luminous, no charging needed, but the tubes are physical objects (not paint) that limit hand and index design. Used on tool watches where guaranteed continuous lume matters; not used on dress or luxury watches.
What modern brands use
Standard Super-LumiNova (most luxury Swiss): Patek, AP, Vacheron, Rolex (post-1998), Omega, Tudor. Lumibrite (Seiko / Grand Seiko proprietary version of Super-LumiNova): brighter initial output, faster decay. Tritium tubes: Marathon GSAR, Luminox, Ball Watch. The choice depends on use case: luxury watches use Super-LumiNova because it's beautiful when applied well and aligns with the no-radiation luxury aesthetic; tool watches use tritium tubes when continuous glow matters.