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Ik ben vanavond eens even op onderzoek gegaan naar de (technische) verschillen tussen Tritium en Luminova. Een aantal van mijn bevindingen deel ik graag met jullie  .
Veel leesplezier! 
Remco
Luminescent
Luminescent
(In French: luminescence)
Having the property to emit light rays. In watchmaking, Tritium is the name given to a radioluminescent substance containing tritium. It was used to coat numerals, markers and hands so they could be read in the dark.
The most widespread system today is LumiNova® which comprises tiny phials of a tritium-based substance. It has replaced the phosphorescent dials for which the first patents were filed in 1878, and dials using radium-based substances which were first patented in 1907.
(bron: hautehorlogerie.org)
Tritium
Tritium (symbool T of 3H) is een isotoop van waterstof met in de atoomkern een proton en twee neutronen, in plaats van alleen maar een proton. De atoommassa bedraagt 3,016049. Tritium is radioactief (beta-verval, ca. 18,6 keV) met een halfwaardetijd van ongeveer 12,26 jaar. De laag-energetische elektronen (betastralen) van tritium dringen niet door de menselijk huid heen. Het is alleen gevaarlijk als het in grote hoeveelheden wordt opgenomen. De lage energie van de straling maakt het ook moeilijk deze te detecteren. Tritium is bij standaard temperatuur en -druk een gas, net als waterstof. Tritium komt in de natuur voor door de interactie van kosmische straling met deuteriumkernen in waterdamp in de atmosfeer; het ontstaat in kernreactors als 6 lithiumkernen aan een neutronenbron worden blootgesteld.
De chemische eigenschappen van tritium zijn nagenoeg gelijk aan die van waterstof. Door de, ten opzichte van waterstof, drie maal zo grote atoommassa zijn de fysische eigenschappen van veel tritiumverbindingen echter meetbaar verschillend van de analoge verbindingen van waterstof.
Het wordt wel gebruikt in atoomwapens en in experimentele installaties voor kernfusie omdat het relatief makkelijk kernfusie ondergaat. Het vindt ook toepassing in lichtgevende stoffen (b.v. horlogewijzers), waarbij natuurlijk de stralingshygiëne bepaalde eisen aan de verwerkingstechniek stelt.
Tritium werd in 1934 voor het eerst gemaakt uit deuterium door Ernest Rutherford, die samenwerkte met Marcus L. Oliphant en Paul Harteck. Rutherford kon het tritium niet zuiver verkrijgen, een taak waar later Luis Alvarez wel in slaagde, die ook deduceerde dat de substantie radio-actief moest zijn, wat juist bleek. W. F. Libby ontdekte dat tritium kon worden gebruikt om de ouderdom van waterlagen vast te stellen, wat b.v. toepassingen heeft bij wijnjaren en grondwatermonsters. De techniek is analoog aan koolstofdatering. Atmosferische kernproeven veroorzaakten in de jaren zestig een duidelijke piek in de hoeveelheid aanwezig tritium in de atmosfeer.
Note: de engelstalig pagina geeft meer info: klik
(bron: WikiPedia)
Luminova
LumiNova ® was chosen as Most Innovative Product in Japan in 1993.
"Glows 10 times brighter, 10 times longer"
What is LumiNova ®
LumiNova ® is a class of newly developed phosphorescent (glow-in-the-dark) pigments which are based on Strontium Oxide Aluminate Chemistry. They are drastically different from conventional phosphorescent pigments which are either based on Zinc Sulfide or on radioisotopes for their self-luminous properties.
LumiNova ® was invented and developed by NEMOTO & CO. LTD. of Tokyo, Japan. Nemoto has been in the luminous pigments business since 1941 and is one of the leading phosphorescent pigment manufacturers in the world.
LumiNova ® Pigments are in the TSCA inventory and NEMOTO & CO LTD., Ltd. was granted the US Patent in 1995 and since then in many other countries worldwide.
LumiNova® Features
· Afterglow period of ten times current ZnS based phosphorescent pigments.
· Activation by a wide wavelength band (200-450 nm) but best results are obtained with an activation energy under 350 nm;
· Initial afterglow brightness of up to ten times that of conventional phosphorescent pigments;
· Increase in luminescence and afterglow with longer activation time;
· Excellent weather and light fastness;
· Free of hazardous and radioactive substances
LumiNova® Applications
LumiNova ® was originally developed to satisfy the current and future needs of the clock, watch and the instrument dial industries, but soon it was found out that like many other new products, the application possibilities are almost limitless.
Applications include:
· Clock & Watch dials;
· Electronic instrument dial pads;
· Home appliances;
· Lighting apparatus and switches;
· Exit sign boards;
· Emergency signage and low level lighting escape systems;
· Aircraft and automobile dials and Instrument panels;
· Firemen's equipment;
· Military applications;
· Outdoor path marking;
· Camping equipment;
· Textile printing and textile fibers;
· Writing & printing inks;
Other applications where a long afterglow and/or light fastness is needed.
(bron: umccorp.com)
Rolex
Luminous Material
For vintage lovers the "correct" luminous material is an important criteria for purchasing a watch.
Like other manufacturers, over the years Rolex has used different kinds of luminous material on the dials, hands and the bezel pearl on rotating bezels. For a watch collector it is important that the luminous material corresponds to the year of production of the watch and that, whenever it is possible, the same luminous material is present on dial, hands and bezel pearl - and even more so has the same colour or toning. Since the luminous material used previously ages strongly (i.e. it becomes yellowed and fragile), with a complete service of the watch Rolex usually exchanges the hands for new ones and often also the dial.
For maintaining the value of a vintage watch is not beneficial to change these things. However, Rolex does this for practical reasons as a full service is designed to return the watch to you in the best possible cosmetic, mechanical and usable condition. However, everyone may decide whether so send the watch to Rolex with instructions to "keep original dial, hands and bezel - DO NOT CHANGE" or allow Rolex do a complete service. However, there have been reports that Rolex has refused to service some watches unless the hands and/or dial are replaced. This can only be due to Rolex’s fears that the old and fragile luminous material may detach and enter the movement.
Again, Rolex’s priority is to return the watch in the best possible practical condition. They are not collectors so they see no value to retaining the old dial, hands or bezel.
Until end of the 50s the luminous material contained radium. Afterwards it was replaced by tritium, which is more weakly radioactive. Starting from 1998, supported by laws, Luminova, a non radioactive material, was introduced. Somewhat later (2000) an improved version was introduced - Superluminova. The advantage of the early luminous materials containing radioactive material was their self luminosity. On the other hand, their disadvantage was that their radioactive decay after some years rapidly reduced the amount of luminosity.
Today only a few late manufactured watches can be found with their tritium material still functional. Most tritium watches do not shine any longer. Luminova and/or Superluminova always shines, but must be ‘charged’ before it will shine by exposing it to a strong source of light. Luminosity decreases quickly with the time in the dark. It is initially brighter than a new tritium watch but fades as the stored energy from exposure to the light source is used without further replenishment. Dial printing allows us to easily identify which material is used:
Letters SWISS
luminous material Radium
used until 1960
radioactive
Letters SWISS - T < 25
luminous material Tritium
used from 1960 until 1998
radioactive, radioactivity less than 925 MBq (25 mCi)
Letters T SWISS T
luminous material Tritium
used from 1960 until 1998
radioactive, radioactivity less than 277 MBq (7,5 mCi)
Letters SWISS
luminous material Superluminova
used from 1998 until 2000
not radioactive
Letters SWISS MADE
luminous material Superluminova
used from 2000
not radioactive
(bron: oysterinfo.de)
De overgang
What does T Swiss Made T mean? What does Swiss Made T<25 mean? What is Tritium?
The "T" means that the watch uses tritium as a luminous material. Tritium is mildly radioactive and will cause the luminous material to constantly glow for many years. Tritium's half-life is 12.5 years. The radioactivity is not harmful if the watch is not damaged, and even then only extensive exposure is risky (such as the people that painted the dials, and watchmakers). he "T" is marked on the dial as tritium is restricted in some closed environments (such as submarines).
T Swiss Made T is the oldest tritium markings on the dial. Rolex reduced the amount of radioactive material to below 25 millicuries, and those watches are marked Swiss Made T<25.
Watches marked either Swiss or Swiss Made use Luminova--which is not radioactive. It must be recharged by a bright light and will glow for several hours. During the transition from tritium to Luminova Rolex used some dials marked T<25 and simply applied Luminova.
Note: Daarnaast is bekend dat 'luminova replacement dials' in de periode tot ongeveer 2003 soms ook met de tekst 'T<25' zijn uitgevoerd. Deze zijn dus niet met Tritium uitgevoerd, ondanks de markering.
(bron: FAQ The Ultimate Rolex Forum)
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Ex-Rolexverslaafde - Xs4all is ermee gestopt, waarmee mijn foto's ook allemaal foetsie zijn. Tja. | |
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