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  1. #11
    Jim Jones's Avatar
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    Quote Originally Posted by Roxi331
    Jim,

    You might check with your local eyeglass lab, often times they are able to polish lens elements out with out any damage to the glass itself for a really low cost, I know I have had this done a couple of times with older lenses and was quite pleased with the results.

    R.
    The requirements of photography far exceed the requirements of eyeglasses. Quality photographic lenses are ground and polished to extremely precise tolerances. I would tolerate deposits on a lens rather than remove glass which can unalterably affect the lens performance.

  2. #12
    JG Motamedi's Avatar
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    Jim,

    In a worse case scenario, use rottenstone or whiting mixed 1:1:1 with ethyl alcohol (denatured will do but everclear or other 95% grain alcohol is better) and distilled water. Rub it on lightly with a soft and clean cotton rag, and wipe the dust off.

    This mixture is a great glass cleaner detailed in 19th century manuals, usually used to clean glass before coating it with collodion. It will in my experience not scatch uncoated glass, but will ruin a coated lens...

    jason

  3. #13

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    Quote Originally Posted by noseoil
    Try some CLR (Calcium, lime, rust) from your grocery store's house hold cleaning section.
    Tim, Isn't CLR like Lime-away... largely phosphoric acid? I used this stuff on the chromed ferules of my bath tub and it ate the chrome away. The lime was gone too! It's possible that I didn't follow directions and used too much, combined with too long of a soak in the solution, but this stuff scares me. Have you used it on camera lenses before?

  4. #14
    jimgalli's Avatar
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    Thanks all. I'm continuing to muddle this. What think ye about furthering Steve H's idea and mixing up some dishwasher wetting agent and letting it soak for a bit? I do have acetone available also. Sure hope the glass isn't actually etched. Yipes, this lens somehow survived 85 years just to fall into my hands and be wrecked!
    He is no fool who gives what he cannot keep..to gain that which he cannot lose. Jim Elliot, 1949

    http://tonopahpictures.0catch.com

  5. #15

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    I would stay second the suggestion of using acetone. I did work for a while at a precision optics firm assembling laser-related optics, i.e., precision stuff and not opthalmics. We used acetone throughout for optical cleaning, although it was reagent grade - cleaner than what you find at the hardware store.

    My gut instinct is to stay away from CLR and other solutions with mystery ingredients.
    My Verito page

    Anyone can appreciate a fine print. But it takes a real photographer to appreciate a fine negative.

  6. #16
    clay's Avatar
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    Astronomers often use collodion for cleaning lenses. Coat it on, let dry and peel it off. The high alcohol and ether concentration in it cleans a lot of stuff.
    I just want to feel nostalgic like I used to.


    http://www.clayharmon.net - turnip extraordinaire

  7. #17
    Donald Qualls's Avatar
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    Regular window glass shouldn't be etched by any acid you'd be likely to have around the house (hydrofluoric acid is another story, but unless you practice glass etching as a craft, you're unlikely to have any on hand), though optical glasses are quite commonly much "softer", chemically speaking (there are a few that are etched by plain water). Alkali is much more likely to cause trouble; I've seen many old chemical reagent bottles, with their ground glass stoppers, in which the stopper was welded in place by even strong ammonium hydroxide; it's quite common for strong sodium hydroxide to visibly etch glass, and even drinking glasses can show visible etching after many cycles in the dishwasher.

    I'd avoid dishwashing detergents and strong alkali, and start with plain distilled water as a soak for the mineral rings. That stuff was dissolved in water once, it should redissolve -- though if it's calcium, it might have undergone a chemical change when the water evaporated. If plain water doesn't work, try carbonated water -- this is a carbonic acid solution, the same acid that eats away limestone to create huge caverns (over geological time, of course). It will convert insoluble calcium carbonate to calcium bicarbonate, which is soluble; it'll do the same for calcium sulfate (gypsum), which account for the bulk of the mineral load in most "hard" waters.

    If plain water will etch the glass, it's already ruined. If not, carbonic acid shouldn't hurt it either -- it's one of the weakest acids going, and only eats limestone by virture of the conversion to bicarbonate.

    Basic rule of conservation and restoration: do the least first. Start with plain distilled water and work up.
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

  8. #18

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    Quote Originally Posted by Donald Qualls
    Basic rule of conservation and restoration: do the least first. Start with plain distilled water and work up.
    I agree... start off slowly with whatever technique you choose to go with.

    Also, instead of cold water... use warm water too. Hopefully, the increased temperature will speed up the reaction AND dissolve whatever is on the glass.

    Cheers

  9. #19
    MattCarey's Avatar
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    Jim,

    I'll refrain from my usual lame humor where I would end up telling you to just send me the lens.

    We have some guys here who do "chemical/mechanical polishing". I could check with them and see if they have a slurry that might be OK on glass. Since they are going for near atomic smoothness, they may be able to come up with something good.

    I would definitely try it on something you don't like first, though.

    Matt

  10. #20
    Jim Noel's Avatar
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    We once had the problem with some lenses from the school. We contacted RIT and were advised to use Listerine. I have used it to clean many things off lenses since that time, including fumgus.
    Jim
    [FONT=Comic Sans MS]Films NOT Dead - Just getting fixed![/FONT]

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