Mid to late 1960s seems to be when blue dials started appearing on Omegas with some regularity.
The blue finish on these early ones was actually
plated like a silver or gold colored dial, they are not painted as we now see on refinished ones. The chemical agents to do this color are so toxic they are no longer available.
The subtle two tone effect on this one is actually only one color blue with the inner and outer parts of the dial being brushed in different directions.
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