Ahhhhhhhhh ye old job coach. Taking me back to my school days when I was wet behind the ears...........back when you learned the basics of optics that the young-ins struggle with today. Back when you were learning a trade to try and use it to make a living in life...............Originally Posted by Darryl Meister
Lesson learned the hard way, Youngins run like hell.
Great stuff, Guys!
Best regards,
Darryl
Darryl J. Meister, ABOM
Jim, I can,t say for certain about government 15, I can say for certain we were always told it meant gray 15. Of all the thousands of blanks we used, I never saw it termed government 15, maybe mick from dallas or JRS can comment further as they were both with B@L at the same time I was.
I never heard of the "government" tag, Even the really old timers there at the time never mentioned it as such. It was always inferred that the G was to represent their version of a gray lens.
The Bausch & Lomb materials that I have refer to the lens color as either "G-15" or "Gray G-15." The color is never referred to as "Gray-15," and it would seem redundant to refer to the color as "Gray G-15," if the "G" already stood for "gray." Also, keep in mind that G-15 wasn't strictly a gray color, but a gray-green color.
So I wouldn't be surprised if the "G" did, in fact, stand for something other than "gray." And it was developed for the military. Still, since the lens was gray/green in color, I also won't discount the possibility that the "G" was just a color reference.
Although I have access to all of the old American Optical stuff through Dick Whitney, who has gone through great lengths to preserve AO history, I'm not sure that anyone has really done the same for old B&L stuff...
Best regards,
Darryl
Darryl J. Meister, ABOM
Although I don't believe that the citation below contains a direct reference to G15 it is a wonderful resource for anyone interested in the history of glass in the United States. You can score a copy on Amazon for about $25.00. The report elucidates the need for good quality optical glass and covers a lot of the early work of B&L and others.
Manufacture Of Optical Glass And Of Optical Systems: A Wartime Problem, May, 1921 (1921)
You don't believe it's still manufactured? Why?
EDIT: I sounded angry, like I meant you were wrong. Think of my response more as confused heartbreak, rather than incandescent rage.
Last edited by standarduck; 12-05-2013 at 07:05 AM. Reason: clarification of tone.
In my pre CR39 photochromic project days I worked on CR39 monomers with dyes that casters could cast for special purpose Rx or sunlenses.
Fun project finding dyes that the peroxide based initiators would not eat up during the preperation and or the cure cycle plus had to do very well in sun exposure fatigue tests!
More as a side project I tried my hand at the G15 color space.
When I referred to it as Gray 15, a long time optical monomer researcher and WWII tail gunner told me that the G was for Government since B&L was commissioned to develop that color space.
Not a lot of evidence but made sense at the time!
Jim Schafer
Retired From PPG Industries/
Transitions Optical, Inc.
When you win, say nothing. When you lose, say even less.
Paul Brown
"Government-15" sounds cooler, anyway!
Darryl J. Meister, ABOM
I do believe that the "G" did indeed indicate that this was a "Government" contract project for the US Army Signal Corps. I do have a book published by the US Army which describes the process that B&L used to develop optical quality glass way back during WWI (the war to end all wars.)
Prior to the work by B&L the US had to import optical glass from Germany and the war put a kibosh on that source. The US had to pay exorbitant prices to third country middle men in order to procure glass for the manufacture of binoculars, periscopes, range finders and other military equipment.
We just moved down to the Rogue River and my library is in a million boxes in the garage. As soon as I unpack I will post a citation on this page.
The G15 lenses are composed of green and gray pigments.This lens has a lower contrast than the B-15 lens allowing for the color and brightness of objects to be softer and more natural.
Really missing KBCO now. Their Polarized was often rejected by dispensers(not consumers) for being green. You could put it side by side in a frame with a ray ban G15 and color was the same. Big ate that product. KbCO had some great product. All gone now. I wish I could get the gray A in a progressive.
We have a green polarized lens in our FreeFocus design, if that's any help.
Thanks JC. The product I miss most was the gray A. Used to get in Image of Fusion. (That may actually be the same product.) I guess not enough market. These were my personal choice. Specialty still makes a lighter gray but not knowing much about those products, and knowing the cost is high from them, I just have not invested the time. I was hoping someone would crank up the old KBCO products. E could not have completely destroyed the equipment and material.
Speed, I checked my pricelist and we have a polarized Grey A in CR-39 and Poly in our FreeFocus as well.
............and to sum it all up
............and to sum it all up, you can tint any un- coated CR39 lens a G15 color that gives you identical absorbtion curves when measured with a good sprectrometer .
I'm not so sure that you could achieve the exact same absorption curves over the entire spectrum. The early positioning of Ray-Ban lenses included the absorption of infrared (thermal) radiation, and I don't think that tinted hard resin lenses provide the same level of attenuation in the infrared spectrum. However, admittedly, and I haven't looked into this in many years.
Best regards,
Darryl
Darryl J. Meister, ABOM
Actually you are right Darryl. I have never measured a genuine G15 nor a RayBan in glass on my Cecil reflectance spectrometer because when I still had my lab in the 60s and 70s we had the lenses, but I had no spectrometer.
I can get good near total absorbance of UV on uncoated CR39 from 270nm to 400nm but on the IR side it is just about nothing, while the color match can be just about the same.
Darryl, did you get the box?
Just got back tonight from traveling all week to find your box waiting for me! Thank you! I'll write more, once I've had a chance to go through it.
Best regards,
Darryl
Darryl J. Meister, ABOM
Love my "Job Coach". And miss Darryl Meister...
Since this thread reappeared "magically", I'll address this: Barberini (Italy) purchased the Schott ophthalmic lens production facility in Meinz Germany and while the Schott technicians are still running it, they are still making glass spectacle lens blanks. As is Corning in France. While the demand for glass in the US is low, it is still very high in the rest of the world, especially in India and Asia.
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