A timely question
Have you ever noticed a difference between the designations located on the bottom of a watch dial? Sometimes they read “Swiss T<25” or “T Swiss T” below the six o’clock marker. But what do these different labels mean? CHRONEXT is here to clear this question right up.
Watches have been created with a luminescent material since the 1900s, rendering them highly legible in unfavourably lit environments. Timepieces are made decipherable in the dark thanks to photoluminescent or radioluminescent properties that coat its hands and indices. Evidently, radioluminescent materials are radioactive, and can thus harm individuals who are exposed to sufficient amounts of it. Therefore, timepieces that utilise a radioluminescent coating on their hands and indices must be regulated to meet specific standards, thus ensuring that the wearers of these watches are exposed to a safe amount of this hazardous material.
Warning: radioluminescent elements
This has not always been the case, though, and in the past, watchmakers have learned the hard way that exposure to large amounts of these materials is deadly. Panerai first developed a process for creating luminous markings in 1915 with the use of the highly toxic based substance Radium. It is likely that Guido Panerai had no idea just how dangerous contact with this substance was. Unfortunately, many of the dial painters from this era eventually died from exposure to the substance.
Following the revelation that radium was a highly toxic substance, watchmakers turned to tritium to provide a glow to their watches even though it was still a radioluminescent substance. Today, the completely health-friendly photoluminescent Superluminova is used in order to provide optimal legibility of watch dials at all times.
The current use of radium has evidently ceased in watch production and has been replaced with much safer alternatives. Today, radioluminescent materials are still used but are typically reserved for professional instruments and are strictly regulated by the standard ISO 3157, which allows two types of radionuclides: tritium and promethium. The use of these materials must be marked on the watch dial.
So what’s the difference?
A “T” on a watch dial indicates that the watch contains tritium-activated deposits.
This marking means that the watch is Swiss and contains an amount of tritium that emits less than 25 mCi.
T Swiss Made T:
This designation again shows that the watch is Swiss but, alternatively, contains an amount of tritium that emits less than 7.5 mCi.
L Swiss Made L:
When you see the designation “L Swiss Made L” on a watch dial, you can be sure that the lume material is photoluminescent.
Providing excellent customer service is one of our top priorities. We deliver your watch fast and with utmost attention to detail. Should you be looking for a specific model which is not in stock, we are happy to source it for you - free of any extra charges. If you would like to sell a watch, our experts will advise you on market developments and the ideal selling price for your timepiece.
Should you have any questions regarding delivery, price or history of a specific model, your personal advisor will be happy to help at any time.
We always guarantee a safe transaction. When you buy or sell a watch on CHRONEXT, your contract of sale is made directly with us. We take legal responsibility for every transaction and provide the highest data security standards, secure payment methods and fully insured shipment. In order to ensure the authenticity and quality of all watches sold through us, every timepiece is thoroughly checked by our watchmakers before it is ever shipped to our customers.
This is guaranteed through our Certificate which you will receive with the purchase of any watch from CHRONEXT - new or pre-owned.
Only the best is good enough for our customers. This goes for prices just as well as for service and security. Luxury watches are hardly ever cheap but there are still significant differences in price levels depending on where you shop. Thanks to our vast global network of suppliers and our low fixed costs, we are able to provide competitive prices at all times.
We scan the market daily for the best offers and always keep our prices up to date. Most important however is that our competitive prices will never lead us to compromise security and quality.