Showing posts with label Rolex dial. Show all posts
Showing posts with label Rolex dial. Show all posts

Tuesday, April 4, 2017

T Swiss Made T" or "Swiss T 25" : what does it mean ?



In order for timepieces to be read in the dark or diving under the sea, a luminescent material is laid on the dial indexes and hands.
Generally speaking, the emission of light is either of radioluminescent type (determined by the radioactivity of the material) or of photoluminescent type (determined by a exciting luminous radiation).

Timepieces featuring radioluminescent emission are mostly designed for very specific uses : military watches, professional divers watches, etc. In this case, the use of radioactive material is strictly defined by ISO 3157 Standard which allows only two types of radionucleides : tritium (3H) and promethium (147 Pm). It is important to specify that these radionucleides emit a radiation of low energy.
ISO 3157 Standard allows an optional marking for timepieces emitting less than a certain value. The marking may be made on the dial as follows :
deposits activated by tritium : T
deposits activated by promethium : Pm

On the other hand, timepieces with a higher value, such as divers' watches, must be marked as follows :
deposits activated by tritium : T 25
deposits activated by promethium : Pm 0,5

The indication "T Swiss made T" means that the watch is Swiss and contains a certain quantity of tritium that emits less than 227 MBq (7,5 mCi).

The indication "Swiss T<25" means that the watch is Swiss and contains a certain quantity of tritium that emits less than 925 MBq (25 mCi).

Most of the Swiss watches use a light emission of photoluminescent type. Some of them bear the optional marking "L Swiss Made L" to indicate it.


The light emitted by the hands and index of the dial is the radiation energy deposited in the luminescent crystals by alpha and/or beta particles. Next to no light is due to gamma rays.

Dial is made with Radioluminescent paint consisting of certain radioactive material mixed with a luminescent crystalline powder. The first radioactive material was radium-226 (Ra-226), but it hasn't been widely used.

Tritium (H-3) and promethium-147 (Pm-147) are the radionuclides of choice.

Other radionuclides have also been used such as strontium-90 (Sr-90) and carbon-14 (C-14).
Zinc sulfide powder has been the most widely used luminescent material.

TRITIUM
Tritium (H-3) is a low energy beta emitter with a 12.3 year half-life. It does not emit gamma rays.
So Rolex T<25 dial means it will last for 24.6 years only.
(less than 25 years!)


Luminova and then Superluminova were developed to avoid the use of any radioactive materials whatsoever. Their intent was to replace tritium lume outright.
Rolex Sports or Professional watches (except the Daytona) generally have <T25 and dress watches like the Date-Just are marked T Swiss T.
This is basically down to the amount of luminous material applied to the dial. The more paint, means more Tritium meaning more radiation as minimal as it is.




Swiss
Luminous Material Radium
Used until 1960
Radioactive


Swiss- T<25
Luminous Material Tritium
Used from 1960 -1998
Radioactive, Radioactivity less than 925 MBq (25 mCi)



T Swiss T
Luminous Material Tritium
Used from 1960 -1998
Radioactive, Radioactivity Less than 277mBq (7.5 mCi)


SWISS
Luminous Material Superluminova
Used from 1998 till 2000
Not Radioactive


SWISS MADE
Luminous Material Luminova (Green
Used from 2000
Not Radioactive


SWISS MADE
Luminous Material Chromalight (blue)
Used from approx. 2008
(introduced with DeepSea)
Not Radioactive


These are what I have researched and may not be all correct , however I hope this give a simple illustration on the type of Rolex Dial being used on your and my watch...


I hope it helps for one of my bog fans asking on this... So now you know T<25 dial on Submariner I always prefer for VR (Vintage Rolex) as all are made on the Golden Period of Rolex. 1960-1998.

HK Snob






Tuesday, September 29, 2015

Rolex Watch Dial Collector (part 1)





This Gentleman has about estimated 300 Dials of various Rolex watch, mostly brand new
he might be one of the Top 20 Rolex Dial Collectors in the World.

Thanks for showing these beautiful Toys!

HK Snob
HK Watch Fever

Friday, September 12, 2014

Creamy Dial of Rolexes



Tabacco Patina Dial
Couresy Picture of http://www.nbtimes.co


Snow White transition dial
Couresy Picture of http://www.nbtimes.co



Date Just or Daytona? Black or White?
Recently I was addicted some of the Dutch, Japanese Danish egg, they are all labeled organic farm egg I don't their Chemical construction, but the colour of the yolk is different.
Reddish orange is the Danish whilst the other ordinary egg is yellow. The taste is also different, the egg white seems chewable, the yolk tasted stronger and the the favour of the yolk is complicated as those 30 years Po Er tea or the Chateau Angelus 1989!
As for Rolex Dial, there is always a tendency of change of colour over the years, say after 20-40 years.
When the so called “White” would becoming creamy beige!
A creamy dial is a few times more expensive than the white one, Well, there might be reason why the colour has changed from white to Creamy? The formula of the creamy luminous paint of Submariner , the aging effect of the ultra violet and heat over the year, it changes colour of the dial, from snow white transition, creamy, yellow patina, tobacco patina… more even more intense of the colour, Likely to be more expensive!
Because of the value of it, more and more fake patina colour dial in the market by some of the genius who applies colouring,  accelerated aging method under some chemical and ultra violet light. This kind of watch dial may not last as the original Rolex Dial.
It takes a lot of experience to tell if that is original natural aging or not, I am not good at this, but I am trying to learn from some of the expert, but for certain uncertain dial, I rather stay away from it…
Side Track
Most of the people like to go Daytona Black rather than White, well, because of the very small number of Black released from Rolex.
The price of Rolex Daytona Ref 116520 Black is HKD$98,000 and White is HKD$90,000.

If I were asked to buy Daytona Stainless steel again, I would rather take the white one for reasons:

1. Cheaper
2. Availablility in Rolex AD
3. Clearer to read the time, ( I use it)
4. More Chance to have the White Dial to change to creamy (really) after 20 years,
Someone said no as the new Rolex dial painting technology has been improved,
Well, Who know what will happen after 20 years.

HK Snob
Watch Fever
HK Snob