my little 2c..

Hello Rick,

the sandwich dials have been produced from the 1930's to the 1960's.
Milling procedure probably has been optimized on the thin aluminium dials over the years.
Also the dial construction has changed, not only the luminous material.

Older sandwich dials show the more open "6" and "9" (both RADIOMIR PANERAI and anonymous "Kampfschwimmer" versions). If you compare these with e.g. a dial in
a 6152/1 watch, you can clearly see the more closed "6" and "9" and also the
different style of the "2" (of 12) and "3". The dial's "3" and "2" (of 12) in watches
with Angelus movements is also lightly different compared to the "3" in 615X refs with Rolex movements. The "2" is more straight on dials for Rolex mvts. while it is more "curved" on Angelus versions, also GPF 2/56.

Sandwich dial (milled numbers and markers) used in ref. 3646:



Brass dial (embossed numbers and markers, painted from top) used in ref. 3646:




Curved "2" and belly "3" in 6152/1 and GPF 2/56 with Angelus:





Straight "2" (of 12) dial in a 6152/1 with Rolex mvt.:



Also note the different font size on Angelus and Rolex versions!

Sorry - i have only these photos at hand right now - not meant as shilling.
Mods - feel free to nuke if not comfy.

Volker

representin' the DNA of Panerai