Super-LumiNova: BGW9, C1 and C3 Compared

Swiss Super-LumiNova is the standard for dial luminescence — a non-radioactive, non-toxic photoluminescent pigment made by RC Tritec in Switzerland. Within that category the grades differ enough to matter, and it is worth knowing which one you are asking for before a relume is approved.

BGW9 is the default. It charges to a cold blue-white and fades toward a neutral. In daylight it reads off-white to pale cream. It is the most widely specified grade for modern and sports applications, and it is the closest match to how tritium lume looked when it was new — which is why it suits a vintage dial that is being taken back to original appearance rather than aged appearance.

C1 runs warmer. In daylight it is cream to pale yellow, and its charged glow is softer and slightly green. This is what we reach for when the brief is to match an aged tritium patina — where the surrounding dial has warmed over decades and a bright white lume would look wrong against it. The warmth reads as intentional rather than discoloured.

C3 is the bright one. It charges to a saturated green, holds that charge longest, and is unambiguously the most legible in the dark. In daylight it is a pale yellow-green. We use it almost exclusively on modern sports pieces where visibility is the goal and period accuracy is not a consideration.

There is a fourth option people forget: custom tinting. RC Tritec can supply de-saturated and tinted variants, which is how you match a specific faded tone on a dial where none of the standard grades sit right next to the existing markers. It costs more and takes longer to source, and on a full relume where every marker is being redone it is usually unnecessary — the point of a custom tint is matching something you are keeping.

In short: matching aged tritium, ask for C1. Modern sports watch, ask for C3. Everything else, BGW9 is the correct default and the one we will quote unless you say otherwise.