Green luminescence is, in fact, the dominant color in the history of nocturnal watch readability. First came radium salts, then tritium: both radioactive, both capable of that yellowish-greenish glow that anyone who has handled vintage military watches knows well. The modern evolution is Super-LumiNova, produced by RC Tritec in Switzerland: no radioactivity, accumulation of ambient or solar light, restitution in darkness for hours. The C3 variant is the brightest in the range — C1 and BGW9 have different intensities and tones — and glows with a characteristic and vivid green. X1 and X2 are superior quality designations used by some manufacturers, such as Bell & Ross in the BR-X3 Night Vision, where the green X2 is admittedly inspired by Head-Up Displays on fighter jets.
The green of emission is not unique: it depends on the formulation. C3 gives an almost acid bright green. Some applications on white lacquer, as in the Projekt 02, produce a softer green because the material is infused into the coating rather than applied as a pure layer. Seiko's LumiBrite achieves a mint green tone, cooler. When the dial is treated with green-emitting white SLN — a technique used, for example, for the numerals of the Lou Gehrig — the daytime color remains neutral and only reveals green in the dark. This is a detail many buyers don't notice until they turn off the lights.
The chromatic bifurcation — green for the hours, blue for the minutes — is a real technical solution, not a decorative one: it allows you to distinguish the hands in the dark without needing different shapes. The TAG Heuer Aquaracer Professional 300 Orange Diver is a recent example, but the principle has existed for decades in military and diving instruments.
On the dial material front, green is not just a matter of luminescence. Malachite is a semi-precious stone with unrepeatable natural veining; Verde Alpi is a marble extracted from the Aosta Valley, used in haute horlogerie for unique dials; green Grand Feu enamel, as in the Blancpain Villeret, requires successive firings at over 800 degrees and produces a color depth that no surface treatment replicates. Japanese wakatake-iro — the green of young bamboo — is a historically codified green in kimono dye culture, brought to the dial by the Seiko Presage HCC002. They are all green, but they have nothing in common with each other except the name.