How to clean off green stuff in Film Compartment ?

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Petrolhead

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Hi All,
I acquired a Canon Canonet QL-17 from the junk store. The film compartment is plagued with green dot like corrosion. Is there any way to clean this off with minimal damage to the black surface of the film compartment. It scrapes of with a fingernail and turns into a green powder but I cannot get it off the surface completely.

Thanks
 

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It looks like the camera was dropped into water at some point in its life.
There is metal corrosion in the entire film chamber. The green is copper alloy oxidation. I wouldn't waste time trying to restore this camera.
 
Try lemon juice on a swab. White vinegar (35% or stronger) might do it too. However, I agree with previous poster, if this is what you see - what does the rest look like, all the moving parts?
 
^ what he said ... it's verdigris, and the camera may well be buggered ... however if you mix the verdigris with a little gum-arabic you can always use it for watercolour painting
 
Probably copper carbonate says the scientist in the family. Copper in the brass and chemicals used to tan leather usually do it.

Regards, David
 
Petrolhead said:
...Is there any way to clean this off with minimal damage to the black surface of the film compartment...
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No, because the green is, as others have said, oxidized copper in the metal below the black paint. Where the green is the black paint is damaged or gone. Cleaning off the green will leave bare, and likely pitted, exposed metal.

The degree of moisture damage seen in the pic indicates massive corrosion damage throughout most or all of the camera. Restoration will likely require a complete tear down, far more work than its worth unless you find such things an enjoyable use of your time.
 
Thanks for all the response. I remembered having read about "verdigris" somewhere but for the heck of me just cannot recall or remember this word when I am writing this post.

One explanation for the corrosion might be the high humidity here in the tropics. We see a lot of similar corrosion not only on cameras but other items as well. RH here is around 60-90 %.To prevent corrosion all our cameras are stored in low humidity cabinets.

The rest of the camera looks fine, no sticky shutter/aperture - probably due to the all year round summer temperature here. The shutter speed works although I have not tested for accuracy. I will just sandpaper off the corrosion and repaint the film chamber in matt black if I cannot remove the verdigris satisfactory.
 
I'm sorry. When you use sandpaper the little abrasive rocks that are stuck to the paper break off. You won't be able to clean the lens without scratching it. Use a chemical fix.

"Vinegar, Salt and Flour: These versatile home staples can be combined to make a paste to clean tarnished brass. Dissolve 1 teaspoon of salt into one-half cup of vinegar, and add flour until the mixture becomes a paste. Rub into the brass, leave for about 10 minutes, then rinse with warm water and buff dry."

http://www.mnn.com/your-home/at-home/stories/how-to-clean-brass-naturally

Ack, just saw the picture.
 
After getting the softer stuff off you may wish to consider sealing the surface somehow to prevent its return. A metal undercoat followed by black paint should do it. But some recommend finger nail polish (whatever works). Incidentally a similar problem was common with old Contax cameras which often developed little "bubbles" under the leather body covering of the camera. Caused by this kind of corrosion of the underlying brass but aggravated by having an electrolytic reaction between different metals in the camera body and rivets. It was so common it was given a name - Zeiss bumps or Zeiss pimples. While your issue is not precisely this one, it is similar and can be dealt with in a similar fashion. Some ideas here on dealing with it.

http://photo.net/classic-cameras-forum/00ALa3

http://photo.net/classic-cameras-forum/00QUjI

http://photo.net/large-format-photography-forum/009R5h

PS The Zeiss bump issue seems to be related to the tannin in the leather covering. Your problem sounds like the camera got damp at some point. Check for other damp related problems in the camera.
 
peterm1 said:
...Incidentally a similar problem was common with old Contax cameras which often developed little "bubbles" under the leather body covering of the camera. Caused by this kind of corrosion of the underlying brass but aggravated by having an electrolytic reaction between different metals in the camera body and rivets. It was so common it was given a name - Zeiss bumps or Zeiss pimples...
Click to expand...

Hi,

And check the backs of Leica R's for them before buying...

Regards, David
 
Petrolhead said:
Thanks for all the response. I remembered having read about "verdigris" somewhere but for the heck of me just cannot recall or remember this word when I am writing this post.

One explanation for the corrosion might be the high humidity here in the tropics. We see a lot of similar corrosion not only on cameras but other items as well. RH here is around 60-90 %.To prevent corrosion all our cameras are stored in low humidity cabinets.

The rest of the camera looks fine, no sticky shutter/aperture - probably due to the all year round summer temperature here. The shutter speed works although I have not tested for accuracy. I will just sandpaper off the corrosion and repaint the film chamber in matt black if I cannot remove the verdigris satisfactory.
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Petrolhead,

This is Vert de Gris (from the French), same color as the one found on old roofs using copper for tiles.
I agree you could still clean it up and repaint it. You could use some metal anti corrosion paint before the matt black.
Cheers
 
Once again thanks for all the responses and words of encouragement, from teaching me a little bit of French to suggesting various concoctions to remove the dreaded verdigris.

I guess my next course of action would be to remove the verdigirs by chemical means and easily available items like lemon juice. Incidentally my wife has some left over lemon juice in the fridge she used for cooking and I will put that to good use.

Also, please exercise extreme caution when you are shopping for a Canon Canonet Ql17 from the great auction site, you never know:D
 
And another junk seller is born. It's ok, if the item is not as described, the buyer can just send it back to you at your expense.

:D
 
photomoof said:
My girlfriend's car is not running well, after reading this thread there is hope, a little sandpaper and black paint?

attachment.php
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Wait until it rains before selling, then it will glisten and sparkle...
 
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