Bausch & Lomb Lens Date Codegreenspun.com : LUSENET : Large format photography : One Thread
Many of you are aware of the code Kodak used to indicate date of manufacture*. It has been suggested that Bausch & Lomb used a similar code in their serial numbers - but the "key" seems to have been lost. Maybe we can reconstruct it. Here's what I propose: 1. Those of you who have a B&L lens with a coded serial number (2 letters followed by some numbers) send me the _complete_ lens info. For example, I have a lens labeled "Bausch & Lomb Optical Co. - Rochester, N.Y.,U.S.A. - Gold Dot - Magenta Dot - Protar V. - 90mm E.F. - f/18 - UF3271". The rear element has a matching serial number (only). Please also include any other info that might help us date the lens: if you are the original owner, when you purchased it; if your lens is still in its' original box, any other labeling info on the box; any sequence info such as "must be after x because of ... but can't be after y because of ...", etc., etc. Please also include any pieces of B&L history or "lore" that might shed light on this problem.
2. I will collect all your submissions for a few weeks and then re-post them here and to the rec.photo.equipment.large-format newsgroup (and perhaps also the cryptology newsgroup)
3. Hopefully a pattern will develop that will help us decode at least part of the sequence.
As you'll notice in my example, I included every piece of info on lens with a "-" between parts of the label. I don't know if there will be any changes in the labeling structure that might help us decode the sequence but, just in case, please send it all.
Also it has been suggested that, if the lens is in a shutter, we might be able to use the shutter info tohelp date it so, if yours is in a shutter please also include; shutter type, size, description, serial number.
If the code is like Kodak's, it's fairly simple - two element, direct substitution, with the second element 1-9 or 0 and the first element 4-9 (the code isn't reported to have started until after WWII --- anybody know otherwise - or when it stopped?). If we're lucky it might be fairly simple -- like if the serial numbers don't reset to zero each year. Sound like fun?? Please take a second to help. The larger the "example pool" we have, the better our chances of success. Thanks Brian Downey
* The Kodak code is CAMEROSITY where C=1, A=2, etc. (e.g. a lens with a serial number beginning with RA was manufactured in 1952).
-- Brian Downey (email@example.com), October 12, 2000