Need to Clean Remnants of Cellophane Off Lens

[J. P. Mose]

I obtained a near mint Linhof Technika Press with Zeiss objectives from an estate sale. There is one problem: The 53mm Biogon rear element was in contact with cellophane for several years and remnants of it are on the surface of the lens. It is a very thin film but lens cleaner will not remove it. Before sending it off to Focal Point Lens or similar, is there anything else I could use that is stronger but won't strip the coating?

Also, I notice that one of the rear elements has about a 1mm air bubble in the middle of the lens! I don't how this got through inspection at Zeiss.....so I'm assuming that it must not effect image quality to any measurable degree?

Please advise. Thanks for your help!

JP

[David A. Goldfarb]

I'd e-mail Focal Point or Zeiss and ask what they would use, and they might tell you. My guess would be naphtha, but I wouldn't try it without getting some advice first.

[Scott Fleming]

I would try freezing the lens to see if perhaps the cellophane might curl. Of course one would needs be very careful about bringing the lens back to room temp. Perhaps put the lens in a good plastic sandwich bag before it goes into tthe freezer. Maybe start out in the fridge and slowly take the temp down before putting it in the freezer.

This is just a guess and I don't really know squat about such things.

What about putting a small square (1 inch) of paper towel over the cellophane and putting two or three drops of water on the paper and keep it nearly saturated for several hours (days?) Perhaps it is possible to rehydrate cellophane. Again, just guessing.

[Steve Hamley]

I've used isopropyl alcohol (common rubbing alcohol) before with stubborn haze and good results.

Air bubbles (air bells) are not defects and are common in older optical glasses.


http://www.glennview.com/lens.htm

Steve

[Ole Tjugen]

At one time the air bubbles were taken as circumstantial eveidence that the lens was made from "Gutes Jenaer Glas" - Good Glass from Jena. For "Glass from Jena", read "Schott".

The special glasses which were so important to the top-end lenses were very difficult to melt, and frequently had bubbles. Too many bubbles, and the glass was rejected. So I would think that Zeiss would have approved your lens.

You have forgotten to mention the vintage of the lens, BTW. I believe the discard limit changed quite a lot through the years...

[Arne Croell]

If the alcohol doesn't work, a last resort might be acetone, which is a solvent for many plastics. I have used it once without problems on an Apo-Germinar from a print shop that had some transparent gluelike material on the lens. It should be ok with the coating, but you have to be careful not to touch any of the metal mounting since it will immediately dissolve any paints, lacquers and dyes in anodized aluminum. Use it sparingly on a piece of lens tissue (Kimwipes are good) and then apply it, several times. I am sure you know this, but never put it directly on the lens (that goes for all lens cleaning solutions). Note that acetone, especially the technical grade available in hardware stores, leaves a residue which can be cleaned with alcohol (after removing the other stuff).

[george jiri loun]

Try a dropp of olive oil, leave it for a moment. Clean then with cloth and with a lens cleaner.

[John Kasaian]

Vodka?? If it dosen't make the cellophane go away, you can drink it!

[Paul Fitzgerald]

Hi there,

The safest way to remove tape residue is 100% Pure Carnauba paste wax and a soft paper towel. It will not damage the glass or coating and will remove the goo from glass, chrome, leather or wood. Take your time and let the wax soften the glue. It will clean up very well and you can remove the wax with lens cleaner if you wish.

Just a thought.

[ernie]

"The safest way to remove tape residue is 100% Pure Carnauba paste wax "

Just a tiny quibble... "Pure Carnauba" is brittle & hard like hard candy. To turn it into paste it is disolved in something, like turpentine. If you don't know what that solvent is, be careful.