Rolex: is the Geiger counter a reliable tool in evaluating the radioactivity on a dial?

Mar 03, 2015,09:52 AM

This article aims to answer a very simple question; Is the Geiger counter a reliable tool in the evaluation of radiation on a watch dial? It is a very simple question, yet the answer is anything but simple. I will give two versions of the answer; a short one and a more detailed one. 

The short answer is that the Geiger counter is most unlikely to be able to offer any reliable insight into the evaluation of the radiation on a watch’s dial. It is not a question of experience or of having tested many watches. The answer is that there are simply too many variables that can affect the use of a Geiger counter to provide anything reliable. This article will explain why the Geiger counter has no place in the process of evaluating a watch.

Evaluating pre-1960 dials

Given the enormity of the subject matter, this article will focus specifically on the use of Geiger counters in evaluating pre-Tritium Rolex dials. It is in this area where there is most contention and as such more value in making the picture clearer. Although the Atomic Energy Commission (AEC) ruled on 13th December 1960 that Tritium would replace the use of Radium in timepieces, one cannot identify a specific time-line for when Radium was stopped in the manufacture of watch dials. The US military were notably patchy in their replacement of radium dials. The US army still used Radium-226 in its dials well into the late 1960s. Furthermore, the 1967 International Standard on luminous materials still permitted the use of Radium in watches, albeit recommending the use of Tritium or Promethium-147. Realistically, one could argue that some watches from the early 1960s will have had Tritium, yet at the same time other watches - even from the same reference - from the late 1960s could well have still been produced with Radium. It is known that some US motor manufacturers started using Tritium on its instrument dials from 1959. As ever with Rolex, there is no definitive truth. Having said this, it seems a reasonable first conclusion to draw that pre-1960, dials are unlikely to have contained Tritium . 

Rolex didn’t just use Radium-226 - they used all sorts of different radioactive materials

The second conclusion, however, is that just because Tritium was probably not in use before 1960 does not mean that Radium-226 was the only other possible luminous material being used. In fact, it is known that a whole range of different possible radioactive materials were being used. For example, as mentioned above, the use of Promethium-147 was still permitted under the 1967 International Standard. It is similarly documented that the US Navy responded to the 1960 AEC ruling by replacing Radium with Strontium-90. The Strontium-90 scare with the Rolex GMT 6542 originated in the late-1950s. The 6542 GMT was, of course, being sold before this scare, which begs the question of how far back was Strontium being used? Finally, not all Radium is the same. Most typically, when one reads about the use of Radium on watch dials, what is being referred to is Radium-226. It is now known that other Radium variants (for example. Mesothorium) were also in use. So, to clarify, the second conclusion that can be drawn is that a wide range of radioactive materials were in use in the pre-Tritium era.  

So if different radioactive materials were used, why is that important for Geiger counter usage?

Why is this relevant with respect to the use of a Geiger counter? Well, different radioactive materials give off different types of emission. Further, the amount of radioactive decay from one material to the next can be very different. Since a whole range of different radioactive materials have been used, this makes identification using a tool as blunt as the Geiger counter fraught with problems. Put simply, a Geiger counter cannot differentiate between various radioactive materials.

For example, Radium-226 has a half-life of 1600 years, meaning that after 1600 years its emission rate will be halved. Compare that with, for example, Strontium-90, which has a half-life of just 29 years. For a watch dating from 1950, the emission rate from Strontium-90 would today be around 20% of its original level whereas for Radium-226, its emission rate would be just 3% less than its starting point in the 1950s. Mesothorium has a half-life of 5.8 years while Promethium-147 has a half-life of 2.6 years. Emission rates will, then, vary dramatically depending on what radioactive material was used. For some materials that were used, radioactive emissions today would be close to zero. Yet, even for materials with long half-lives, like Radium-226, emission rates may have fallen dramatically. How?

Does anyone know how much decay had already occurred in the radioactive materials used by Rolex in the 1950s?

Just because Radium-226 has a half-life of 1600 years, it does not mean that any watch that had Radium-226 applied will still have high radioactive readings today. Radium-226 is a naturally occurring substance. What if the Radium-226 applied to a watch in the 1950s had already been decaying for 10,000 years? The fact is, nobody knows how much decay had already been experienced in batches of Radium-226 applied in the 1950s. Varying degrees of prior decay will result in varying degrees of radioactive emission today. This leads to the third conclusion. Since it is not known how much decay a radioactive substance had already experienced when applied in the 1940s and 1950s, it is theoretically possible that a dial that had Radium-226 applied might have negligible radioactive readings today if the original Radium had already experienced significant decay. Given this theoretical variance, can a Geiger counter reading, on its own, provide definitive evidence either for or against the existence of Radium-266 on a dial? I posed this question to Cambridge University physicist. His answer was very simple. He argues that the only way to be definitive would be to undertake a direct examination of the radioactive material. A Geiger counter reading would be expected to vary from one decayed Radium-226 type to the next and thus quite useless in identifying the type of radioactive material on a dial. Quite useless. 

As a radioactive material decays, it breaks down into different substances that, in turn, break down further and further. Each process involves emission of different types of radioactivity, with varying half-lives

The situation becomes more complex yet, as once a radioactive material decays, it breaks down into different types of radioactivity that can emit different types of particle. For example, Radium-226 is primarily an alpha-wave emitter with some gamma.  However, once Radium-226 decays (albeit slowly) it also starts to emit beta particles. At the end of its decay, it actually turns into lead, which of course acts as a shield against radioactivity emission! Strontium-90 is a pure beta-emitter, and it decays relatively quickly into a compound that is also a beta-emitter. Mesothorium is primarily a beta emitter, but on decay breaks down into a multiple range of different compounds emitting alpha, beta and gamma. Promethium-147 is a pure beta emitter and it decays primarily into beta-emitting compounds, though the end of its decay does see some alpha emission. With varying rates of decay and with varying particle emissions, an instrument as blunt as a Geiger counter simply cannot differentiate what type of radioactive material is present on a dial. Radioactive material becomes a soup of different compound emitters.

Geiger counters cannot detect alpha waves

So, where does this leave us? Most Geiger counters cannot measure alpha waves. So, when a typical Geiger counter measures radiation emission from a watch dial, one thing it is NOT doing is measuring alpha particles. Alpha particles would not pass through a sheet of paper let alone a plexi or a watch case! But, most importantly, the vast majority of Geiger counters do not have the capacity to measure alpha. If there are beta or gamma particles that are being emitted, then the typical Geiger counter will supposedly pick those up. It takes about 8mm of aluminium to stop beta particles, so beta will make its way through plexi. Yet, the most commonly used radioactive material is thought to have been Radium-226, which is an alpha emitter. If one tested a watch known to have had Radium-226 applied, then what the Geiger will pick up will most likely be the beta and gamma emissions that have emerged following Radium-226 decay. In reality, this is what the Geiger counter is most likely measuring. Would one expect Radium-226 to produce large amounts of beta and gamma particles given that it is an alpha producer? The answer is …. maybe. The “maybe” depends on how much decay the Radium-226 had already endured and how much Radium-226 had been originally applied. Is there any recorded evidence from Rolex of this from the 1940s or 1950s? No. So, theoretically, a dial that had Radium-226 applied might emit almost pure alpha (which would record nothing on a Geiger counter), or it might record high levels of beta and gamma (which would be detected by a Geiger counter), or alternatively it might produce no alpha, beta or gamma at all, depending on how decayed the Radium-226 was to begin with. From a scientific perspective, it is impossible to be definitive using just a Geiger.

The radioactive emissions on a dial will also be impacted by what Rolex decided used as binders

Regrettably, it gets yet even more complicated because not only were Rolex experimenting with different radioactive materials, but in addition they were also experimenting with different artificial binders for the radioactive materials. Typically, a substance like zinc sulphide would be applied to a dial along with Radium. The zinc sulphide would glow when it was hit by the radiation emitted by the radium. However, after a period of time (around 3-4 years), the zinc sulphide would break down as a result of the radiation bombardment. The “glow” from the lume came not from the Radium but from the fluorescent compound with which it was bound - typically zinc sulphide. The Radium would also often degrade the varnish in the paint that held it in place, resulting in flakes of Radium breaking away…flakes that can be in dust form that can easily work free of the dial (and watch). Different binding compounds, of course, can break down into substances which can also emit different types of radiation. It has been shown that one of Rolex’s trade secrets was the addition of the radioactive substance, Mesothorium, to a dial. This would elongate the light intensity for the first five years. Thereafter, the zinc sulphide deterioration would kick-in. When exactly did Mesothorium start to be used? There is evidence to suggest its use as far back as the 1920s. It was certainly still in use in the late 1950s. Do we know which dials used Mesothorium and which used Radium-226? No. Can a Geiger counter differentiate between them? No. 

One further very clear conclusion comes from this and that is that without direct compound analysis, it is simply impossible to determine what type of radioactive material is present on a pre-tritium watch dial. A typical Geiger counter could plausibly detect beta or gamma emissions, but it cannot determine the source of that emission and has no hope of detecting alpha particles. 

How important is the quality of the Geiger counter?

This brings the next area of uncertainty into focus. How important is the quality of the Geiger counter being used? Most commonly used hand-held Geiger counters measure the amount of micro-Sieverts emitted. A “Sievert” is a measure of the equivalent biological effect of the deposit of a joule of radiation energy in a kilogram of human tissue. In effect, what most hand-held, non-professional, Geiger counters measure is “energy”. That is VERY different to measuring radioactive emission. Most professional Geiger counters measure in terms of “Becquerel”. A Becquerel is a derived unit of radioactivity. That is what should be being measured. Some radioactive material emits small amounts of particles but these particles may have very high energy. That would record high micro-Sievert readings, but actually the amount of radioactive decay might be quite low. What needs to be measured by a Geiger counter is the amount of decay that is being experienced. Each time that radioactive material decays, it emits a particle. Counting those particles and relating them to the material is where the Geiger counter adds value. For a Geiger that can measure only energy, for example my own Geiger (see picture below), it is not especially useful at all for this purpose.

The $64,000 question

If a Geiger counter shows no beta or gamma emission, does that mean that a dial can be invalidated as containing no Radium? This is a crucial question, but thankfully I think the answer is clear. A lack of radiation  detection on a dial can occur from a number of valid reasons.

Firstly , if a Geiger counter is used incorrectly or is faulty or measures the wrong objective, it will fail to measure the gamma or beta emission correctly. In the case of the Geiger counter that I bought and that is commonly used by watch collectors, there is a very specific way of measuring. At the back of the detector there is a Geiger-Muller tube. This is the part of the device that actually catches the radiation emission. If one points the Geiger-Counter at a watch in the wrong way, i.e. with the GM tube away from the watch, then expect the readings to be very distorted. As the manufacturer of the Geiger counter is very clear stating, unless it is used in the proper way, results will be affected. I am sure others may have their own stories to discuss. Here is my evidence.

The first picture is using my Geiger pointing straight at my 5512 from the early 1960s. It shows a reading of 0.34 micro-Sieverts. That is marginally above background radiation. 

However, once I used the Geiger counter in the correct way, the reading from my 5512 dial rose quite materially. As can be seen from the following picture, the reading rose to 5.48 micro-Sieverts - over 16 times as much as the previous reading.

Secondly , since it is entirely plausible that a radioactive substance other than Radium-226 has been used on a pre-1960 dial, it is entirely plausible that the half-life of that substance is low enough to have resulted in significant decay resulting in minimal levels of radiation…possibly even zero when measured today. Since we do not know with any certainty what radioactive material was used and with what artificial binder, there is no way of deriving that source through an instrument as blunt as a Geiger-counter. We also have no idea how much decay had already been experienced by the radioactive material applied in the 1950s. Maybe it had already decayed significantly. 

Thirdly , there are other very pertinent factors that can also lead to a lack of beta or gamma emissions from a watch dial. The most relevant is the fact that Rolex were not consistent in applying radioactive material amounts. In fact, they varied how much radioactive material was applied from very low to very high amounts. How do we know that the amounts varied so much? Well, Rolex documentation shows it. The following is an extract from Rolex. It shows a Rolex supplier (Universo) offering to vary the intensity of the radium lume on the hands. If you wanted your Rolex to shine like a beacon, that could be arranged. Equally, if you wanted it to have low radium content, that too was on offer. Suppliers of dials and hands offered not only different lume substances but also different lume intensities. 

This represents another very clear and important conclusion. From a purely theoretical standpoint, it is very clear that pre-1960 dials could have varied enormously in terms of how much radioactive material was applied. It is not a debate, but a fact. Theoretically, two identical watches that were manufactured in the 1950s might have consecutive serial numbers and have been untouched for the last 60 years, yet one may have had high levels of radium applied and the other may have had negligible amounts of radium applied. This fact is often something that is ignored by many experts. I have seen perfectly legitimate early GMTs declared “wrong” simply because there was no radium “glow”. A little knowledge is a dangerous thing. I think it is fine to argue that science is king, but the application of that science needs to be conducted by scientists who know how to conduct it properly. Science that is mis-applied is dangerous.  

Yet, when experts tell us that routine testing of specific watches always results in a similar radioactive result, then one would seemingly need to think that it was typical for a specific watch to have had a similar radioactive treatment. That almost seems like scientific evidence! This is especially the case for watches that were made within very narrow production periods. An example of this is the Rolex Submariner 6200. One expert told me that having tested 20 of these models, all 20 recorded readings of around 3.0 micro-Sieverts. I spoke with another expert who told me he had tested 5, and that 3 out of the 5 had no radiation readings at all, one had a reading of 0.8 and one had a reading of 2.3. I have tested a small number and found the range of readings to vary from zero up to just over 3. What does this tell me? Well, given that we know that both the type of radioactive material and the amount used could vary, a mixed outcome seems entirely plausible. Further, one could also argue that measuring the radioactivity through micro-Sieverts was actually the wrong yardstick through which to make any judgment……

The bottom line is that it seems impossible to hold any conviction about how much or how little radioactivity a pre-Tritium Rolex dial should have. Any conclusion to the contrary is of course possible, but so far there has been no scientific evidence to that end. 

Facts versus empirical observations

There is another key issue to mention. Since we don’t know the facts, experts create the facts based on empirical observations. Yet, for some watches, the number of examples is so low that it is statistically foolish to draw conclusions. Take my 6610 Red Depth, for example. I would estimate that there are probably fewer than 20-30 or so genuine versions in existence all within a narrow serial range. If I tested 10 and they all had a similar Geiger counter reading to mine, does that mean that another that appears completely authentic on all criteria would be wrong if it recorded a different level of radiation altogether? Statistically, with such small sample sizes, sampling error will be large and it would be foolhardy to draw conclusions. Sampling size is crucial. For rare watches that have very low numbers for testing, creating “facts” from such small sample sizes is very unscientific. Scientists would NOT do it. Empiricism based on a sample of 20 isn’t scientific. 

My own observations

Which brings me to my own empirical testing. With the help of my Cambridge University physicist, using a professional Geiger counter as well as my own Geiger counter, I tested a number of my own watches as well as watches from friends. What I found was extremely interesting. Firstly, Geiger counters that measure just energy (ie Sieverts) are not really very good at detecting Becquerels, so not really the right tool to be using. Secondly, using a professional Geiger showed that three-quarters of the watches that I tested recorded about 80-90% beta emissions and about 10-20% gamma emissions. I asked the physicist if this meant that these three-quarter of the watches were lumed with the same material. His response was that it was absolutely impossible to determine that since the plexi was preventing any alpha particles leaving the watches. Only through full mass spectrometry would it be possible to determine the composition of the lume. So, even though I could argue that my dials were emitting beta/gamma in roughly an 85/15 ratio, it could still tell me NOTHING about what type of material was on the dials. This type of analysis was possible using a professional Geiger counter. The hand-held Geiger version, like the one I own, is essentially useless as it provides less information still. Although its fun to detect the radiation using a hand-held Geiger, my Cambridge physicist could draw no conclusions at all from the readings. 

In the spirit of empirical observation, my early 1960s Submariner 5512 recorded a reading of just over 5 micro-Sieverts per hour. I challenge anyone with an early 1960s 5512 to record the emissions of their watch. I will make a guess - the variation in readings will be significant. From zero up to double-figures. Why do i suspect this? I tested 6. They were all perfectly correct. And they all had very different radioactive emission. Of course, to be scientific, I should probably need to test 100 or so. But expect a wide variance. That’s Rolex for you. Does anyone want to make a definitive claim about what radiation should be emitted by an early 5512s? I would truly hope not.

The role of science

Science has a role in the evaluation of a watch’s dial. When conducted by proper scientists and when conducted under proper laboratory conditions, it is possible to determine what has been applied to a dial. Using a Geiger counter to determine this answer is, in the view of all of the experts i asked, simply not possible. Even if one used proper science and subsequently evaluated the composition of a dial, given that Rolex provided such uncertainty on what they applied and in what quantities, could science really provide a categorical answer to whether a dial was authentic or not? Maybe…..but most likely maybe not. I think there are far better ways to evaluate a watch. 

It is time that experts recognised that using cheap hand-held Geiger counters does not serve the watch collecting community.       A little knowledge is a dangerous thing. 

This message has been edited by Baron on 2015-03-03 09:52:50 This message has been edited by Baron on 2015-03-05 07:04:19

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10 "facts"

 By: Baron - Mr Red : March 3rd, 2015-10:24
1) Fact - Rolex used to lume their watches with varying amounts of radioactive material. Sometimes a lot. Sometimes very little. Hence today, those watches that received a lot will tend to emit a more, whilst those watches that received virtually none wil... 

Binders! That is an important factor.

 By: amanico : March 3rd, 2015-11:46
I have a TR 900 which glows like hell... Before getting it, I looked at the luminous indexes with a lot of attention and a big magnifier... No relumed at all... I started to Wonder how it was possible, and I found the responsible: Binders! Best, Nicolas

It is also why nobody should invalidate a watch because of no glow.

 By: Baron - Mr Red : March 4th, 2015-09:48
I have seen a dealer argue that because a lume didn't "glow" under UV, therefore there could be no radium left. Well, if the binder had disintegrated, there would be no glow. Bottom line..... there has been an enormous amount of BS spread over the radioac... 

If your dial is not luminous anymore, this could be a solution to give it some light.

 By: amanico : March 4th, 2015-11:08
The TR 900 was made in 1964. Guven the short life of the Promethium 147, militaries could be interestedin finding a solution to give their indexes some luminous.

the binder will only glow if there is radioactive emission...

 By: Baron - Mr Red : March 4th, 2015-11:50 if a substance with a very low half-life is used, replacing the binder will have no impact..... ....unless the decay is into something that has a longer half-life.... and that is also possible

wanna quick answer ???

 By: marcello pisani : March 3rd, 2015-10:29
no , especially if you don't use it properly .. LOL LOL LOL

and moreover ...

 By: marcello pisani : March 3rd, 2015-10:33
don't forget the old wise proverb : " no knowledge is better than a small knowledge ! " LOL LOL LOL more serious comments on this monumental post from Joe coming as soon as possible ...

As Marcello said .............

 By: Ray Nicol : March 3rd, 2015-11:05
That's why I like to check with my own F>>>>>>>> EYES

Wow !!! Fabulous post Joe

 By: johnnya : March 3rd, 2015-10:34
Thanks for a very informative and interesting post Regards John

An excellent discussion!

 By: gensiulia : March 3rd, 2015-10:38
An excellent discussion, which brings to the light a multitude of interesting factors. a pleasure to read and share 100% your own conclusions. thanks, i really liked a lot. best, Chris

A lot of knowledge is...

 By: Ares501 - Mr Green : March 3rd, 2015-11:02
a lethal thing :) Great post dear Joe One for records for sure Best D

100% pure agreement on that, Joe. wonderful work, great article.

 By: amanico : March 3rd, 2015-11:43
There are so many factors, so many things we are still discovering about our dear vintage watches, Rolex or not, which should lead us to a certain prudence and a big humility. I tried to dig the topic of radioactivity, I gave up. Ok, there are some import... 


 By: navyeight : March 3rd, 2015-12:38
Top top work 110% correct Well I hope Philip reads this and holds his hands up, but I doubt it :)

Great post--

 By: Fargo : March 3rd, 2015-12:45
--food for thought for all!!!!!

What a great post Joe !!! I also ........

 By: Ray Nicol : March 3rd, 2015-13:20
Tested many watches over the last 3 months including a Rolex 6538, 6610, 6200. I used the Radex 1212 Geiger counter which I purchased off ebay for £100 (there were on offer a couple of months ago Lol wonder why ) and a lot of people seem to be trying them...  


 By: Ray Nicol : March 3rd, 2015-13:25

Question on example of half-life?

 By: wmhmatt : March 5th, 2015-06:54
"Radium-226 has a half-life of 1600 years, meaning that after 800 years its emission rate will be halved." Shouldn't this read, " Radium-226 has a half-life of 1600 years, meaning that after 1600 years its emission rate will be halved."

excellent spot.....

 By: Baron - Mr Red : March 5th, 2015-07:02
thank you...will correct it

Excellent post!

 By: Anatol : March 3rd, 2015-13:48
Joe, thank you very much for that excellent post! It is very rare these days to find scientific rather than emotional approaches to critical issues determining the value of our watches! Thank you for that!

Absolutely excellent article

 By: fatboyharris : March 3rd, 2015-14:06
The use of Geiger’s, its method of application, the resultant observations, outcomes and the development of assumptions and conventions have been discussed for some time, unfortunately IMHO too much was taken for granted. More recently as others have delv... 

by the way ...

 By: marcello pisani : March 3rd, 2015-22:33
please accept a public " many thanks John ! " for the excellent work you have done since many years on this stuff : without your contribution lot of things would be still unclear. chapeau !

John...welcome to PuristS

 By: Baron - Mr Red : March 4th, 2015-01:49
Welcome to you and thanks for posting. It is indeed on the back of so much research from others that we gradually learn. And, as Marcello states, you have been a leader in promoting this subject for a number of years. It is on the back of research from pe... 

Thank you for yours and Marcello's kind words

 By: fatboyharris : March 4th, 2015-03:31
Its very much appreciated, rarely does one get the opportunity to make a small contribution to the knowledge base and understanding of a particular hobby that has been under the microscope for so long. It's nice to follow in the footsteps of many who have... 

What an epitome of an analytical write-up !..A marvellous post to bookmark !.. :))

 By: hs111 : March 3rd, 2015-23:29
..Really enjoyed every single paragraph ! - Thx for this splendid work ! Best, hs

Thanks H

 By: Baron - Mr Red : March 4th, 2015-09:46

Excellent article Joe - Here are my results....

 By: 964RS : March 4th, 2015-03:26
Like probably quite a few people, here and elsewhere, following the discussions on VRF about the use of this machine and the 'outing' of watches based on it's results back in November I decided to purchase one also and go about checking all my watches and...  

Thanks Jason.....

 By: Baron - Mr Red : March 4th, 2015-03:38 basically your findings appear fairly similar to mine. Readings of between zero and double-digits with no apparent logic on what does and does not score high radioactivity detection. I am sure others will contribute to this learning database, but f... 

"Radioactive material becomes a soup ..

 By: marcello pisani : March 4th, 2015-08:03
of different compound emitters " LOL LOL LOL

Alpha-beta soup

 By: Baron - Mr Red : March 4th, 2015-09:45

Joe i am so proud of you

 By: Iceman : March 4th, 2015-08:53
Thank you for such a detailed and scientific study on this subject. Well done my friend. BRAVO... iceman


 By: Baron - Mr Red : March 4th, 2015-09:07
....this is a subject that needed to be addressed in a straightforward and factual manner. Collectors deserve to be provided facts rather than have science misused. Thanks for your words.....

Great post !

 By: DrStrong : March 4th, 2015-09:52
thanks for the great write up, another reference post on the forum. Unless you use gamma spectrometry, you cannot identify any kind of radioactive element. Especially with a Geiger counter, which was not invented for that purpose by the way. The Geiger co... 

thanks Jeff....

 By: Baron - Mr Red : March 4th, 2015-10:16
....a subject that needed addressing

not easy to add something to ..

 By: marcello pisani : March 4th, 2015-10:00
such a perfect work but .. in order to add further salt .. here is an extract from a document made in the 70's by the US NRC ( discovered by our special agent Fatboyharris ) about modifcations on half-life of radioemitting materials by binders : ''It is g... 

As a former licenced investigator for radiolabelled studies in humans

 By: MTF : March 4th, 2015-12:15
Baron, I concur with the physics conclusions and arguments that you expressed. i must admit that I've never tested watches. ;) Regards, MTF

Fantastic and important post, as well as beautifully written--bravo!

 By: tomvox1 : March 4th, 2015-14:06
And thanks to Roberto for giving me the heads up! John Harris has been banging this same drum for a while now and when the Geiger originally surfaced a few years back as the new tool of choice for collectors, certain men of science such as Keith C. and ot... 

The question is why mark the dials at all back in the 60's

 By: fatboyharris : March 4th, 2015-15:45
I t wasn't until the revised International Standard for luminous dial materials released in 1975 was there any International requirement for all dials to be marked with the luminous material used. Prior to that from the 1967 International standard, only d... 

esatto !!!

 By: marcello pisani : March 4th, 2015-23:45
now I'm dead beaten after too much dancing ... LOL LOL LOL


 By: Baron - Mr Red : March 5th, 2015-02:48
Thanks for your comments and opinions. They are always welcome. I can think of one good reason why I would not want to remove the plexi off my radium dials....well, several maybe. First, alpha particles are quite dangerous in terms of biological impact. I... 

Great read, Baron!

 By: blomman Mr Blue : March 4th, 2015-14:21
Thank you very much for the education! One point on which material was used... Since several different dial maker delivered to Rolex during this period of time... It would be interesting to know which maker used which material. Best Blomman

I don't know the answer to that...

 By: Baron - Mr Red : March 5th, 2015-05:27
....and i am guessing nobody on the planet does either.... But it is a great question because it would seem most likely that the various different suppliers used various different materials...making it even harder to provide some kind of standardised rule... 

Dial production evolved over time and it became a multi supplier

 By: fatboyharris : March 6th, 2015-01:44
manufacturing process. Dials were originally supplied fully lumed,. by the dial manufacturer but towards the late 50's and certainly by the early 1960's we know that Merz and Benteli (M&B) were applying the lume to the tritium dials and hands not the ... 

Thank you for the input, John!

 By: blomman Mr Blue : March 6th, 2015-07:33
Yes, very interesting. Best Blomman

Thank you for the education.

 By: sutats : March 4th, 2015-15:13
Sadly it also reminded me of the tragic plight of the Radium Girls. RIP.

Excellent and well researche report on the Gieger and it place in Rolex collecting

 By: Bill : March 6th, 2015-17:14
And yes. It has no place in Rolex collecting. It seems it has been a that there are some who use to justify their position but remains without merit. It has all to do with financial gain/favor. Thanks for the great report. Bill

Very nice reading...

 By: Ale (aka Fuciliere) : March 8th, 2015-12:29
...agree 101% with Baron. I'm relatively new to the vintage Rolex world but there is one thing I'm learning quite fast: a crappy watch in the hands of a guru becomes gold no matter why, and a golden watch in the hands of the guy next door can become crapp... 

Very nice Mr Baron .....I would like to know...................

 By: Rolex Paul : March 10th, 2015-13:22
2 things I would like to point out here, why is the Vintage Rolex forum deleting post's like this it is a valuable information we all still like to learn and this subject needs to be addressed. Also there is someone here who is owed a massive apology the ... 

For clarification you are saying the person who used the geiger at the was wrong

 By: Bill : March 11th, 2015-08:06
Not to put words in your mouth. Just want understand your POV. A watch was wrongly classified due to the miss use of the geiger. And unfortunately the seller suffered as well as the would be buyers both deprived of the pleasure. Thank for your thoughtful ... 

Ok let me explain the story briefly here........

 By: Ray Nicol : March 11th, 2015-10:09
My Rolex 6200 was put up for sale at Christie's in Geneva in November 2014, the day before the auction a certain dealer put a picture of the watch up against a Geiger counter and took a picture and posted it, the picture was taken in a way that was either...  

Some simple rules.....

 By: Baron - Mr Red : March 12th, 2015-01:38
.....if technology is going to be used in the verification of a watch, it MUST be conducted using professional equipment and by a professional who understands the science. Absent that, any observations by watch pundits seem to be redundant. Of course, des... 

well on the contrary ...................

 By: marcello pisani : March 12th, 2015-03:24
I'm not surprised at all ! no real argument behind .. just an endlessly attempt to brainwash people. this is the most disappointing matter !

On this Marcello...i disagree

 By: Baron - Mr Red : March 12th, 2015-03:32
ANYONE who holds themself to be an expert in vintage Rolex and who also argues that the Geiger is useful MUST defend that position. A failure to defend the usage poses many questions. Some will make inferences....I genuinely hope that a counter opinion to... 

Well Joe

 By: Iceman : March 13th, 2015-22:42
unfortunately it does show a clear lack of character on the Persons who preach the geiger. Too bad they are not engaging thru constructive dialog on this but instead, they choose to delete the article in VRF. Shame on Them. Iceman

no problem ....

 By: marcello pisani : March 11th, 2015-11:19
there are so many fishes in the sea ... LOL LOL LOL

Be safe or be saved

 By: iceheller : March 14th, 2015-16:40
You got a very interesting and detailed write up on watch radiation. I am not a radiation expert or with IAEA but work in radio-pharma industry. The GM counter can detect the basic three + one type of radiations (alpha, beta and gamma + x-ray thought not ...  

Thanks Iceheller

 By: Baron - Mr Red : March 15th, 2015-02:22
Thanks for your comments. Very helpful. I have a couple of things to add to what you stated..... There are way to convert GM counter uSv/hr reading to Bq if you know the calibration source radiation material and the efficiency of your GM counter for the p... 

What is the Binomial distribution of the samples?..............

 By: fatboyharris : March 15th, 2015-03:02
see wikipedia for an explanation.................................what is the established norm of the sample, what is the range of standard deviations from the norm, which would indicate whether something is an exception to the norm etc, etc, etc. It is no... 


 By: Baron - Mr Red : March 15th, 2015-08:55
......I am still waiting for someone to tell me just how decayed the Radium-226 that was used in the 1950s was. Had it been decaying for 10,000 years prior to being applied by Rolex to their dials....maybe just 5000 years? Maybe it was brand "new" with no... 

Thanks for yr remark but...

 By: iceheller : March 15th, 2015-03:39
We all know sample size can affect a lot of things, u can play around with sample size just to achieve the p-value u desire if u use it for comparison or hypothesis testing. Beside u need to assume samples are all homogeneously/normal distributed, indepen... 

Better test method.

 By: iceheller : March 15th, 2015-03:59
A better test here may be using a chi-square as yr is more like a categorical "yes or no" radiation detected on watch dial to begin with. Unless u r measuring how high and low level of radiation, then some other instruments/equipments and tests like simpl... 

Hey Iceheller....

 By: Baron - Mr Red : March 15th, 2015-08:23
.....its good to raise these issues. Here is where we differ..... 1) A specific Rolex reference may have had its dial produced by different dial manufacturers. Rolex used multiple suppliers. Similarly, Rolex used numerous suppliers for the hands on their ... 

Arh Type II error.

 By: iceheller : March 16th, 2015-06:50
Well, chi-square was suggested for using simply "yes or no" radiation on watch dial which is categorical as you mentioned that you cannot accurately measure the radiation on the rolex dial just using GM counter due to the fact that you do not know the bin... 

Its not that Chi-squared wouldn't work....

 By: Baron - Mr Red : March 16th, 2015-06:59
.....rather that its result would not be useful.

Absolutely fine.............

 By: fatboyharris : March 15th, 2015-08:37
You are quite right there are many ways of testing samples, Binomial distribution is usually used in the testing of samples to ensure compliance to manufacturing tolerances on a production line. The issue about sample sizes is IMHO further complicated by ... 

John...i think that brings us to a conclusion....and that is....

 By: Baron - Mr Red : March 16th, 2015-10:40
.....scientifically, there can be no conclusion. LoL Unless, of course, someone knows differently...... slightly louder LoL


 By: iceheller : March 16th, 2015-13:33
Well with so many unknown, then more we should use infer statistic to draw a conclusion, well that what scientific community ( forget to mentioned I used to work in one of asia top university for a period of time doing technical work and involved in a han...  

I did play around with that theme....

 By: Baron - Mr Red : March 16th, 2015-13:56
.....i took a Geiger reading through the plexi...then placed am 8mm aluminium shield over the plexi. The emission was reduced by about 80-90%....presumably the beta radiation being blocked.

Thanks, here mine.

 By: iceheller : March 16th, 2015-19:17
Background (fluctuate below 1.0uSv/hr) [URL=] [/URL] Detecting radiation emission from BALL Aviator (T100 rating) [URL=] [/URL] Detecting radiation emission from BALL Engineer Hydrocarbon (T25 rating) [URL=] [/URL] ...  

Your conclusion is?

 By: Baron - Mr Red : March 17th, 2015-04:50


 By: iceheller : March 17th, 2015-23:27
Forgot to conclude, GM counter can indeed be use to check for the presents of radiation on watches, just like X-Ray can be used to detect fr cancerous mass in the body. But if u want to know the extract type of radiation then u use other instruments, like...