That was my post. Your not going to try this with an expensive Marquee are you. It was an experiment with a cheap scratched ECP lens. It cleaned up the outer lens of the scratches, but in the process removed the anti-reflective coating. In this case the lens was junk anyways so I had nothing to loose. What's your plan for it?
I know I don't have to explain to you the down side of this. Basically what I did was to find something that spun at a constant rate of speed, I used an old turntable set to 78 Rpm. I then used one of those rubber discs that you use to remove jar caps with so as to supply the needed friction between the lens and turntable (absolutly clean so that you dont scratch the back side of the lens). I used an old diaper soaked in warm water with cheap toothe paste, plain white with no additives to sweeten your breath or make deeper scratches in your lenses. Smear some on the cloth and go for it giving equal time to the whole surface. You probably will not be able to save the anti-reflective coating and will have to buff it all off. You will be suprised at how thick that coating is. Once you have gone through the coating in one place you have to remove the whole thing (you know why). The lens will look like new, looking at the projector but the trained eye will pick up thr reflections on the screen. Once you've removed the problem area rinse with warm water, reinstall on the spinning devise of your choice and dry buff with the cleanest softest cloth you can find. If you hadn't just brought this up, I would have forgotten that lens is still on my projector, And I'm still useing it. Do I need to put a disclaimer in here? The lens I did this to had zero value as is so I had nothing to loose.
Can anyone comment on the difference the lack of lens coating on the outside of the outermost lens makes to the projected image?
It's hard to decide between a coated/scuffed lens and a lens that looks new but lacks this coating.
In my case (Sony 1271) Inner parts of the lens assembly also appear coated and these are in perfect shape since they haven't been exposed to wear. My unit was probably a rental in a previous life thus accounting for the wear on it's case and outer lenses.
I don't believe I've played any vinal in 10 or 12 years but the turntable I used was of the very very high precision type. Now it looks like something from a pottery shop. I think Ken (KBK) would throw up if he saw what I did to this turntable. The only reason he would let this slide is because it was done in the interest of science.
Hey guys...where is the anit-reflective coating? Is it on the outside of the lenses (closest to the screen), on the inside, or on the back of the lens (closest to the CRT face)? I have minor scratches on 2 of my lenses (HD-8 REV B) that look like they were caused by the lens caps. I would like to know If I can use this trick to fix them without damaging anything else (ie. the anti-reflective coating).
A single scratch or two, does not warrant a polishing. My XG135 had a single scratch on one of its lens, and caused no effect to the image. Light each point of the CRT spread out and go through the whole lens surface before converging to a single point on the screen (aka pixel). A single hairline scratch obscures only about 0.1% of the light (unform light reduction for the entire screen) meaning no effect on the image at all.
Only do this trick on lens that are pretty much trashed...
If you were to go back to the original post on this subject the lens in question looked as if someone tried to clean it with a scotchbrite pad. I was just fooling around with it because it was junk anyways. I was surprised at how fast the toothpaste was able to bring back it's original luster, minus the anti-reflective coating of course. I had done some searching around and as of yet not been able to come up with a user installed replacement coating.
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