BolCo Condenser Lenses
A couple of large old condenser lenses has recently come into my possession. The boxes say they were made by BolCo (which I take to mean British Optical Lens Company), and the specifications read as Pl/Cx (i.e. plano-convex), diameter 4½ inches, focal length 7½ inches. The convex side is aspherical, and the plane side has a narrow elevated outer rim, about 1/16 wide and less than 1/32 high. The lens glass has a faint greenish-blue tint.
I would very much like to know a little more about these magnificent chunks of glass. BolCo, of course, supplied the "Bloomed Bolco lens" for the popular pre-war Twin cameras, and I have been told that the company produced lenses for slide viewers and projectors too.
My two lenses now show me that BolCo also produced condenser lenses for enlargers; do any of you know whether the company made complete enlargers as well, or just supplied other companies with glass?
I trust that APUG, with the immense knowledge stored in its members, will once again be able to come to my aid.