Watch Lume Types Explained: Chromalight, Super-LumiNova, Tritium and Radium

Watch lume is the luminous material applied to hands, hour markers and bezel pips so that a watch can be read in the dark, and on luxury watches it has gone through four generations: radium paint until the early 1960s, tritium paint until about 1998, the non-radioactive strontium aluminate compounds sold as Luminova and Super-LumiNova since then, and Rolex's own Chromalight, introduced in 2008, which glows blue rather than green. Each generation glows differently, ages differently and leaves different markings on the dial, which is why lume is one of the first things a dealer looks at when dating or authenticating a Rolex. This guide explains what each material is, how long it glows, how it ages, how the dial text tells you which one you are looking at, why patina adds value on vintage watches, and what to check on lume before buying used. Bizak & Co. sources every reference mentioned to order; the used Submariner collection is where the tritium and Super-LumiNova generations sit side by side.

Last reviewed on September 25, 2026 by Filip Biczak. Prices are dated observations, not quotes.

Watch lume types at a glance

The years are for Rolex and are approximate; Rolex has never published changeover dates, and the transitions overlap by a year or two depending on the reference and the dial stock in hand. The Rolex Submariner collection page describes Chromalight on the current watches, and the Rolex watch care and service page covers the parts policy that decides whether an old dial is kept or replaced at service.

What is radium lume and is it safe?

Radium paint mixes radium salts with zinc sulphide; the radium's radiation excites the zinc sulphide and makes it glow without any charging from light. It was used on military and civilian watches from the First World War until the early 1960s, when its health effects on dial painters and the risk to wearers ended its use. The radium is still radioactive, since its half-life is about 1,600 years, but the zinc sulphide has long since broken down, so a radium dial no longer glows. It reads as a dark brown or black lume plot, often with a burn mark on the dial or a shadow on the inside of the crystal where the radium sat. A radium watch is safe to wear on the wrist but should not be opened at home, and a watchmaker should handle the dial with care. On Rolex, radium appears on early Submariners, GMT-Masters and Explorers up to around 1963; the shift to tritium is marked by the T that appears in the dial text.

What is tritium lume and why does it turn cream?

Tritium paint works the same way as radium but uses tritium, a hydrogen isotope with a half-life of about 12.3 years and far weaker radiation, mixed with a phosphor. It glows on its own without charging, which is why tritium watches were the standard for divers and the military from the 1960s to the 1990s. The trade-off is that the glow halves every 12 years, so a tritium Submariner from 1990 has lost the great majority of its glow and one from 1970 is dark. The phosphor and its binder also age: they yellow to cream, caramel or, in the best cases, an even pumpkin orange, and they can crack, crumble or fall out of a hand. That ageing is the patina that vintage buyers pay for, and an original tritium dial with even, matching patina on dial and hands is worth substantially more than the same watch with a service dial. Rolex marked tritium dials "T SWISS T" until the 1980s, then "SWISS - T < 25", meaning the tritium activity was under 25 millicuries; the marking is how you tell a tritium dial from a later one at a glance. Our vintage Submariner authentication guide goes deeper on matching lume between dial and hands.

Luminova and Super-LumiNova: the non-radioactive lume

Luminova is a strontium aluminate pigment developed in Japan by Nemoto in the early 1990s; it absorbs light and re-emits it, is not radioactive and does not degrade, so it can be recharged indefinitely. Super-LumiNova is the Swiss-made version produced under licence, and it is the lume on nearly every Swiss watch made since about 2000, including current Patek Philippe, Audemars Piguet and Richard Mille references. It glows green in its standard grade, with other colours available, and it is brightest in the first hour after a charge before fading through the night; the brightness depends on how thick the layer is, which is why a dive watch with deep lume plots outglows a dress watch with a thin line on the hands. Rolex used Luminova for a short period from about 1998, on dials marked "SWISS" only, then Super-LumiNova on dials marked "SWISS MADE" from about 2000. Because these compounds do not age, a Luminova or Super-LumiNova dial from 2002 looks the same as it did new, which is the practical difference from tritium: there is no patina and there will not be any. The Patek Philippe Nautilus page and the Audemars Piguet collection pages list the luminous material on each current reference.

What is Rolex Chromalight?

Chromalight is Rolex's own luminous compound, introduced on the Deepsea in 2008 and rolled across the professional range in the years that followed. It is a strontium aluminate material like Super-LumiNova but formulated to glow blue rather than green, and Rolex claims a longer glow duration than the standard green compound; in practice the blue reads as dimmer at first and then holds for longer through the night. Rolex applies it thickly on Submariner, Sea-Dweller, GMT-Master II and Explorer hands and markers, and more thinly on Datejust and Day-Date hands. Newer formulations from the early 2020s are visibly brighter than the first generation and are sometimes described as Chromalight with a whiter daytime appearance. Chromalight does not patinate, so a 2010 ceramic Submariner has the same white markers today as when it was sold, and the same will be true of a 2026 watch in 2050. The lume colour is one of the quickest ways to distinguish a modern Rolex from a Super-LumiNova one in a dark room: blue is Rolex from 2008 on, green is everything before or everyone else.

How to date a Rolex from its lume and dial text

The dial text has to agree with the serial, the reference and the hands. A tritium dial in a 2005 case is a replacement or a swap; a "SWISS MADE" dial in a 1990 case is a service dial, which is honest if disclosed and priced as such, and a problem if it is being sold as original. Our Kermit 16610LV guide covers the Super-LumiNova era and our 16613 Bluesy guide the tritium-to-Luminova transition on one reference.

Does lume patina add value?

On tritium and radium watches, yes, and often substantially. An original dial with even cream or pumpkin lume, matching hands and no cracks is what vintage buyers are paying for, because it proves the dial has never been replaced and it cannot be manufactured; a Submariner 5513 or 1680 with a good original dial is worth far more than the same reference with a service dial, and the difference has widened as the supply of untouched dials shrinks. On Luminova, Super-LumiNova and Chromalight watches there is no patina to value, so condition is judged on wear and originality alone. Prices follow: on 25 September 2026 Bizak's sourced catalogue listed a pre-owned Submariner 116610LV Hulk, a Chromalight watch, at US$21,681, and current Chromalight Submariner 126610LN examples at US$13,484 to US$15,785, all sourced to order; tritium-era references are quoted individually, because the dial condition moves the price more than anything else. Those figures describe what we saw and will move. Our Submariner price guide shows dated asks across the generations.

Buying a used watch: what to check on the lume

• Dial text matches the serial. Radium, tritium, Luminova and Super-LumiNova each have their marking; a mismatch with the case's production year means a replaced dial.
• Dial and hands match. Lume on the hands should be the same colour and the same state of ageing as the markers; bright white hands on a cream dial mean the hands were replaced at service.
• Even patina. On a tritium dial, plots that have yellowed evenly are worth more than a mix of dark and light plots; blotchy or greenish plots may have been exposed to moisture.
• Relumed dials. Under ultraviolet light, relumed plots glow bright and evenly while original tritium barely glows; a strong glow on a 1970s dial is a warning.
• Cracked or missing lume. Look at the hands under a loupe; tritium lume in hands cracks and falls out, and a hand with a hole in the lume will need relume or replacement.
• Glow test on modern watches. Charge under a bright light for a minute and view in the dark; blue means Chromalight, green means Super-LumiNova, and a weak or patchy glow on a modern watch suggests aftermarket parts.
• Price against the band. A tritium watch with a perfect original dial offered well under the market is the single most reliable warning sign.

Our authentication process includes ultraviolet inspection of dial and hands on every vintage watch we source.

Quick answers

What is Chromalight on a Rolex?

Rolex's own luminous compound, introduced in 2008, which glows blue rather than green and is designed to last longer through the night than standard Super-LumiNova. It does not age or change colour.

Is tritium lume dangerous?

Not on the wrist. Tritium's radiation is weak and cannot pass through the crystal or caseback, and most of it has decayed on watches from the 1990s and earlier. The dial should still be handled with care when a watch is opened.

Why does old Rolex lume turn yellow?

Tritium paint and its binder age with time, light and humidity, turning cream, caramel or pumpkin. The tritium itself decays with a half-life of about 12 years, so the glow fades as the colour deepens.

What does T Swiss T mean on a Rolex dial?

That the dial's lume is tritium. "SWISS - T < 25" means the same, with the tritium activity under 25 millicuries. Both indicate a dial made before about 1998.

Does Super-LumiNova wear out?

No. It is a strontium aluminate pigment that charges from light and does not decay, so a Super-LumiNova dial from 2002 glows as it did new. It does not develop patina either.

Request a Submariner sourcing quote

Tell us the reference, dial and lume generation you want, preferred year range, condition and whether papers are required, plus your budget and timing, through our sourcing enquiry form. We confirm the specific watch, photographs, papers and final price before you commit. Catalogue entries: pre-owned Submariner 116610LV Hulk, Submariner Date 126610LN; browse the used Submariner collection, the Submariner collection, the Sea-Dweller collection, or sell or trade your watch.

Related reading: Vintage Submariner authentication guide · Submariner 16610LV Kermit guide · Submariner 16613 Bluesy guide · Submariner 126610LN guide.