What Is a Replica Fifty Fathoms Tritium?

A replica Fifty Fathoms Tritium is a copy of the Blancpain Fifty Fathoms dive watch. It uses tritium lume on the dial and hands. Tritium is a radioactive isotope. Watchmakers used it in the 1960s through the 1990s. The lume ages to a yellow-brown color. Replicas use real tritium or a simulated lume to mimic this vintage look.

What Is Tritium?

Tritium is a radioactive isotope of hydrogen. It has a half-life of 12.3 years. Watchmakers mixed tritium with phosphor. This created lume that glowed without light. Tritium replaced radium in the 1960s. The glow fades over time. The lume changes color from white to cream to brown.

How Does Tritium Age?

Tritium ages in two ways. First, the glow fades. The phosphor burns out. Second, the binder breaks down. The lume may crack. It turns from white to yellow-brown. This process takes years. A watch from 1965 may have dark brown lume today. The color shift is uneven. Some parts are lighter.

How Do Replicas Mimic Tritium?

Replica Fifty Fathoms watches mimic tritium in several ways. Some use real tritium lume. Real tritium is rare and radioactive. Most replicas use simulated lume. They apply a pre-aged paint. The paint is yellow-brown. Some use lume that ages on its own. The dial gets a matte finish. The hands and bezel get matching lume. The goal is to look like a vintage watch.

What to Check on a Replica Fifty Fathoms Tritium

  • Lume color: Check for uneven patches. Real tritium ages in spots.
  • Glow: Tritium glow is faint. It may not glow in the dark.
  • Dial: Look for a matte finish. Glossy dials are not tritium.
  • Hands: The hour and minute hands have lume. The seconds hand may have a dot.
  • Bezel: The bezel insert has lume. It should match the dial.
  • Case back: Check for a serial number and model number.
  • Movement: Check the beat rate. Vintage movements beat at 18000 bph or 21600 bph.

Tritium Safety

Tritium emits beta particles. They cannot pass through the watch crystal. The risk is low. Do not open a tritium watch. If the lume flakes, do not inhale it. Replica tritium may not be real tritium. Ask the seller about the lume material.