What is G-15?

[drk]

I know the B-15 tint is a RayBan oldie. 15% transmission.

Is the G-15 the gray?

What I'm looking for is the term for the gray-green combination...

Thanks!

[Manual]

G-15 is the green lens.

[finefocus]

G-15 is the green lens.

G-15 is green/grey; not a true grey like TruColor from AO, and not green/green like original Rayban.

[Uncle Fester]

From wiki- No mention of a specific color name.

http://en.wikipedia.org/wiki/Ray-Ban

[finefocus]

From wiki-

http://en.wikipedia.org/wiki/Ray-Ban

Where we learn about that B&L classic, the Indoorsman.
Dick and Darryl, correct me if I'm wrong, but wasn't "Rayban" originally the green lens tint, later supplemented by G15 and G31, the greyer greens?

[OIC]

not green/green like original Rayban.

Green/green was G-31 (higher transmission; lighter green). Correct on G-15 green/gray and 15% TLT.

[drk]

Optiboard: the coolest. Thank you.

[harry a saake]

Optiboard: the coolest. Thank you.

what the term actually means, ever since 1933 when this lens was developed for pilots, is it transmits 15% of light, and gets rid of 85% of light, G-31, 31 % transmission, gets rid of 69%, there was even a G-50 developed for the European market at one time.

[Darryl Meister]

Dick and Darryl, correct me if I'm wrong, but wasn't "Rayban" originally the green lens tint, later supplemented by G15 and G31, the greyer greens?

Yes, I believe that the original Ray-Ban lenses were green. Later, G-15 and G-31 were introduced as gray-green lenses, as the others have pointed out.

As a treat for you guys, I have attached an excerpt on the different Ray-Ban lenses from Bausch & Lomb's old "Job Coach":



Best regards,
Darryl

[finefocus]

Yes, I believe that the original Ray-Ban lenses were green. Later, G-15 and G-31 were introduced as gray-green lenses, as the others have pointed out.

As a treat for you guys, I have attached an excerpt on the different Ray-Ban lenses from Bausch & Lomb's old "Job Coach":



Best regards,
Darryl

Yes, different Rx's, different thicknesses, were a problem with glass lenses. This problem was "solved", kinda, with Uniform Density blanks; a bit like modern polarized lenses, they were a clear blank with a colored front layer.

[Darryl Meister]

This problem was "solved", kinda, with Uniform Density blanks.

Yeah, their uniform density lenses are actually covered on the back of this page!

Best regards,
Darryl

[rbaker]

Job Coach! Ahhhh

[harry a saake]

Yeah, their uniform density lenses are actually covered on the back of this page!

Best regards,
Darryl

actually the color problem was mostly with plus lenses. What we did in those days was to grind the lower plus thicker, and the higher plus thinner, worked most of the time.

[Darryl Meister]

actually the color problem was mostly with plus lenses.

Yes, the visual implications were certainly more dramatic with plus lenses, because the variation in color occurred primarily through the center of the lens, which of course is positioned directly in front of the eye during primary gaze.

Say you have a G-15 glass lens that transmits 15% of light at a standard center thickness of 2 mm. Ignoring losses due to reflectance, each additional thickness of 2 mm will reduce transmittance to 15% of the preceding transmittance value. The transmittance therefore drops exponentially with center thickness.

So, at twice the center thickness, or 2 * 2 mm = 4 mm, the transmittance of that G-15 lens through the center becomes 15% of 15%, or only 2.25%. This would result in a lens that would be considered too dark by many wearers. At three times the thickness, transmittance drops to roughly 0.15^3 = 0.34%.

With minus tinted glass lenses, the lenses become darker toward the periphery, resulting in a raccoon-eye effect. While still unacceptable cosmetically by many wearers, the vision through the center of the lens was more or less equal to the transmittance of a plano lens.

Best regards,
Darryl

[Dave Metzger]

I still have my job coach, and the Helpful Hints booklet. I always preferred G15 over Truecolor D.

[Chris Ryser]

It has all been said, so I have nothing more to say.

Only that thanks to uncoated CR39 we can now tint any color to any transmission we want.

[drk]

For you guys that go back before the '70's, were Rx sunglasses practically limited in their appeal due to tinting issues with glass lenses? Or were they just a luxury item in a less affluent time?

Did people use full-rim glass clip-on's back then?

[waynegilpin]

Color variation with strong lenses was easily resolved by "ultracoating" (?) the lenses. Similar to an AR coating today but with color. Problem was the color could scratch or flake off.

Most obnoxious pt I every had was a guy who keep saying he didn't want tinted (meaning coated) sunglasses because he had scratched the color off on his previous pair. Warned him that he would not be able to see through his +7D Rx in glass Calobar D. He insisted on ordering them, and couldn't see through them because the color was too dark at the center (Duh. What did I warn you about?). He then went into orbit when I wouldn't refund his money or remake them at no charge.

[rbaker]

For you guys that go back before the '70's, were Rx sunglasses practically limited in their appeal due to tinting issues with glass lenses? Or were they just a luxury item in a less affluent time?

Did people use full-rim glass clip-on's back then?

Back in the "good old days" before plastic lenses came into general use tinted glass lenses such as G15 or Truecolor were the rule up to three or four diopters, plus or minus. Beyond that we sent the lenses out to be coated. Of course before the advent of photochromic lenses we sold a pant load of sunglasses.

I don't know about "less affluent times" but we made a far greater percentage of profit back then. It was said that being an Optician was a license to print money. No insurance. No El Cheapo Schlock Houses. No merchant MD's selling glasses. How sweet it was.

[waynegilpin]

"Did people use full-rim glass clip-on's back then?"

Clips available with a nine base curve to fit over the aphakic's glasses. Boy, those +15.00 Rx's were fun. Pts in every week to get them adjusted. Walk out the door, bump into something, and turn around and walk back in. Couldn't see with the glasses and couldn't see without them.

[finefocus]

"Did people use full-rim glass clip-on's back then?"

Clips available with a nine base curve to fit over the aphakic's glasses. Boy, those +15.00 Rx's were fun. Pts in every week to get them adjusted. Walk out the door, bump into something, and turn around and walk back in. Couldn't see with the glasses and couldn't see without them.

As I'm retiring soon, I cleaned out a bunch of cabinets and found 3 sets of Welsh MED trials; +12.00 or better in Sirmonts, Ronsirs, and Polymils. A trip down memory lane, but not really a good trip. We just couldn't help people as much back then.

[standarduck]

As a dull aside, the G-15 tint was special (I think) due to the addition of ferrous oxide, which helped to block infra-red (along with teh UV filter properties of the tint). This made (techincally still makes) them very suitable for equatorial countries, which UV is not the only damaging factor from the sun.

I think I sent myself to sleep.

[drk]

No, that post is relatively exciting.

For Optiboard, at least.

[rbaker]

As a dull aside, the G-15 tint was special (I think) due to the addition of ferrous oxide, which helped to block infra-red (along with teh UV filter properties of the tint). This made (techincally still makes) them very suitable for equatorial countries, which UV is not the only damaging factor from the sun.

I think I sent myself to sleep.

I don't believe that anyone still manufactures spectacle crown glass. Since the demand for glass lenses is so low it would be impossible to economically produce them. I'll bet that any rough or semi finished blanks used today were made years ago.

[Jim Schafer]

I believe the original B&L G15 designation stood for Government 15, since the color space was developed for the USAAF (United States Army Airforce)......