Rolex ref 5075 (from 1947) big bubbleback 勞力士大泡泡背

This is another version of the big bubbleback ref 5075 with the straight lugs and fully covered bubbleback movement with rose gold bezel. I first saw the watch on fb in March 2020 but it was taken out from the web. This watch was recently being listed again and I immediately went to the shop to check it out.

The Rolex Big bubbleback series leading to the Datejust consists of the following 

Rolex ref 4467 (solid Gold from year 1945-1949)  
Rolex ref 5030 (Solid gold) , Bi colour steel and gold 5031, 5075, 6031 from year 1949 - 1950)，
Rolex ref 6075, 6074 (Bi colour from year 1950 - 1953)
Rolex 6104, 6105 (Bi colour modified A296，from year 1951 - 1953) 
Rolex 6304 , 6305 (A296，from year 1953 - 1956)
Rolex Datejust 6604, 6605, 6609, 1600, 1601,1603, 1607, 1625 (from 1959 - 1977 onwards using Butterfly movement calibre generation features cal. 1065 and later cal. 1565 and 1575.)

I was looking at getting a Rolex 6075 big bubbleback from a seller initially but he was not very friendly and I have decided to give it a pass as 冇緣份· Like what they said, one door shut and another one opened. I am lucky to be able to get a better condition and straight lugs big bubbleback 5075. Really thankful! 

Coming back to the Rolex bubbleback series give me great joy as it has rekindled the special relationship with my hobby. There are many new collectors going after the Rolex sports models but for me, the Bubbleback series (from 1930-50s) an the Prince series (1930s) are the real backbone of the Rolex brand.

我比較喜愛1950年代出嘅勞力士大泡泡背大倌 5030,5031, 5075, 6031 除咗有紅date外,錶殼兩耳中間還是保留橫端,帶住濃厚官財仔嘅味道!

Rolex 6031, 5075, 5031

In its history of "Radium" usage... "Radium" was discovered to be very lethal in its radioactive dosage causing harmful side effects particularly to the Dial painters or those that have been widely exposed to the highly radioactive substance Radium" and such was in this past infamous incident which had previously occurred way back in 1917 (please see link below)

http://en.wikipedia.org/wiki/Radium_Girls

Eventually by late 1950s "Radium" had to be phase out completely and as quickly as possible then by watch producers worldwide. It was later ONLY became compulsory that the usage of "Tritium" with much Milder dosage of radioactivity level(eg. <25 micro Sv/h) be marked accordingly either by adding the plot "T" at 6 o'clock position of the Dials...in later production of watches by Rolex in particular from early 60s. 

As such, some of the Vintage Rolex dials were replaced during service during the 1960s with Tritium lumious instead of the Radium.

It was also during the same Transitional Period soon after the change from "Radium" to "Tritium"...most of the remaining Dials in stocks. that were previously contracted & made by the relevant Rolex's Dial suppliers had to be re-marked or re-printed with the additional "T" or "T<25 variant" plots to indicate the MILD radioactivity usage of of "Tritium" instead of "Radium" on the available Dials which had been Pre-printed with "SWISS" at the 6 o'clock position of ALL the remaining Dials in stocks...believed to be in limited quantities then. (Information from the forum)