Can someone give me a little lesson about Lens Blooming?...

[slashmaster]

I have a nice example of a super 8 bell and howell 346a such as this one http://www.tias.com/13486/PictPage/3923581926.html I also own a decent regular 8 version of the same thing which is almost the same as this one here http://www.tias.com/13486/PictPage/3923724723.html

I can swap the lenses between these projectors and have noticed the one from the super 8 gives a better image than the one from the standard 8 in either projector. Not just with my projectors, I've got a friend with almost the same 2 projectors and it's the same story... I thought the reason was because the one for the super 8 was painted black on the inside to absorb unwanted reflected light. But today I was learning about Lens blooming. A coating added to some lenses... Perhaps one of these lenses has it and the other doesn't? When was lens blooming invented and when did it become common?

[cameratech]

Blooming is a type of tarnishing that occurs on certain glass types and has the interesting effect of increasing the transmission of light - on lenses this creates a brighter, higher contrast image. It was noticed in the 19th century that some older telescopes seemed brighter than newer ones, but not worked out until nearly the 20th that blooming was the cause. Taylor, Taylor & Hobson were first to try artificially blooming lenses to reduce surface reflections in the early 1900s, but Dr Smakula of Zeiss was the first to create chemical coatings that replicated the effect in 1935. The technology was considered a war secret by Germany for a while! By the 50s most lenses were being coated. Multi-coating probably starts around the 60s or even 70s.
Here's a good explanation of how lens coating works:
http://rick_oleson.tripod.com/index-166.html
Post-war projection lenses for standard 8 would most likely be single-coated (and I've seen examples branded "bloomed" from the late 40s), multi-coating becomes more common in the Super 8 era. Coatings tend to increase lens speed and contrast, and control flare, but other things like sharpness or aberration control are more likely to be in the optical design. One of the things new coatings allowed was designs with more elements, since the light loss at each glass to air surface could now be minimised.

[slashmaster]

Thanks cameratech!... That site is just what I wanted to see! Now this coating would be on both sides of each element right? Or just one side? And the thicker the coating the more it brings high contrast to anything red right? So If I can find a lens with a thicker than usual coating will that make my films with typical eastman red tint look higher contrast? Even if it does nothing to bring out the other colors?