27 July 2005

I tried out the colloidion as a lens cleaner last night.

I was reluctant to jump right into coating my mirror with it since I have seen a report of it removing coatings from inferior or damaged lenses. I was having trouble thinking of something to test it on that wasn't plastic (it also has been reported to be capable of dissolving plastics although nobody has reported experiencing this) when I remembered an old Bausch & Lomb glass magnifying glass buried in my desk.

I checked the glass and it had dirt on both sides so the first thing I did was to clean one side. Then I put a big fingerprint in the center of the dirty side. I started painting the colloidion on the glass trying to see if it would be possible to do it on my mirror without having the brush make contact with the mirror. I found that that would be nearly impossible. I think the best procedure would be to pour a quantity of solution on the mirror and swirl it around until it dried. The solution is not anywhere as viscous as I had anticipated it would be given its intended use. It seems like you would have to spend days applying layer after layer of the stuff to an actor before you had a thick enough patch to credibly simulate a wound.

Getting it off the lens is even more of a problem than getting it on without touching the lens. It forms a very thin coating on the lens, especially at the edges. I tried to peel up the edge by scraping my fingernail across it, something I don't want to do to my mirror, and found that it was impossible. I built up a thick spot on one edge by placing a drop of solution there and not spreading it out and it didn't help any. The British kit comes with adhesive tabs that are used to start the peeling process. I assumed that they were applied after the solution had dried but don't see how that could be. I don't know of an adhesive you could peel from release paper that would have enough adhesion to the film to overcome that of the film to the glass. I was able to get the peel started by placing a piece of paper on the film and painting over it with several more layers of colloidion so that it became part of the film. You need to peel the entire sheet of film in one piece since you will have a lot of difficulty starting the peel again if part of the film remains attached to the lens/mirror.

Where the film peeled off the glass it left it spotless. My fingerprint was gone and there was no sign or dust or anything else. If I can learn to apply it and remove it without doing damage it will be a great way to clean my photographic and astronomical optics.

I did not get my film peeled off the glass intact and was not able to get the remainder of it started to peeling. I remembered that it is supposed to be water soluble so removed the magnifying lens from its metal film and ran it under hot water in the sink. That completely dissolved the remaining film. While this would work for my mirror and waterproof binocular the same technique could not be used for my photographic lenses. And if I am going to have to wash the mirror in water anyway I might as well just do the whole job in the sink. But this technique might come in handy of something nasty gets on the mirror and can't be blown off before washing.