See my post #10 from early this year: https://www.largeformatphotography.i...17#post1627917
Quotes information from C.P. Goerz American Optical Company dated August 1953 regarding the new Red Dot Artar.
As far as a blue dot, Goerz Optical Company, Inc. made the Blue Dot Trigor, engraved on the bezel "Trigor" plus a blue dot (like the red dot and the gold dot.)
I have also seen examples, mostly on ebay, of lenses engraved "Goerz Optical Co., Inc" and "W. A. Process" (but not "Trigor") with a blue dot.
David
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