What the Heck is a Zeiss Bump?
"Zeiss Bumps" are hard bumps that appear under the leather covering of vintage cameras.. These greenish bumps "grow" over time, the result of a build-up of a hard, waxy chemical substance. produced when copper rivets on the camera body react with adhesives and moisture in the leather covering.
In the construction of their cameras, Zeiss used a coating of shellac-based glue to affix the leather to the camera body, and when the glue did not completely cover the copper rivets, it allowed contact between the exposed rivet heads and the leather. This reaction caused the hard bumps to grow and push up under the leather. These bumps were most notably present in early Zeiss cameras, hence the name. but these bumps are present in many brands of vintage cameras.
Can Zeiss Bumps Be Removed?
In most cases, yes, depending mostly on the condition of the leather. Generally speaking, there are two approaches for bump removal: 1) in-place removal where, with a razor blade, a cross-cut is made on top of the bump, opening up an "incision," allowing the bump to be removed, and 2) removing or peeling back the leather from the body, removing the bump, and re-gluing the leather after putting a sealant over the copper rivets. The bump is more likely to grow back with the first method since it is more difficult with a small slit to put a sealant over the rivet. The first method can also be a bit unsightly as it leaves obvious cuts in the leather. That said, the second, preferred method of complete leather removal is dependent on the condition of the leather and being supple enough to come off. Sometimes the leather is so brittle that removal is not an option.
One other challenge for bump removal is that if they are large enough, the leather can be permanently deformed and you won't be able to smooth out the leather after removal. This stretching also has a tendency to change the texture of the leather.
Of course, a third option is to leave the bumps as they are and enjoy them as part of the character of the camera!
Another thing to note: The presence of Zeiss bumps might indicate that the camera has lived in a humid environment, and it may be a sign that other parts should be checked out for potential issues such as fungus in the lens and galvanic corrosion on the film loading/frame counter mechanisms.
(Photo courtesy of uwittehh on ussrphoto.com)