The phenomena commonly called "Zeiss Bumps" are typically hard bumps under the leather of the camera back. These bumps are caused by the growth of waxy hard lumps of a chemical product that is the result of the reaction between the copper in the rivets holding the pressure plate and/or the film roller to the inside of the back, and the chemicals used to tan the leather.
Zeiss used a thick coating of shellac based glue to hold the leather on the back. Holes due to incomplete coverage of this glue allow contact between the exposed rivet heads and the leather. The growth of the chemical causes hard lumps under the leather. The material is a deep green hard waxy substance that does not adhere to either the leather or the metal.
In most cases Zeiss bumps can be removed. The success of this operation depends upon the condition of the leather. The better the condition of the leather, the more successful the removal.
It is important to understand that my process for bump removal consists of removal of the leather without damage to the leather or its surface. Once the leather is removed, the leather and metal are cleaned and three coats of a sealant is applied to the rivet top to prevent a new bump forming. Then the leather is re cemented in place in one piece.
Out there in the rest of the world the standard method of bump removal is to use a razor to cut slits on top of the bump. Then the bump material is extracted from the hole in the leather, and the leather is re glued in place so that hopefully the cut damage won't show for a while. My opinion of this method is that it is destructive of irreplaceable original Zeiss leather, is indicative of stupid lazy work that has only profit in mind and is just plain old fashioned camera butchery at its worst. It doesn't take long for the bump to re grow when removed by this method, the new bump spreads open the cut, and the only way to properly correct the situation is to replace the leather. Here is a picture of the results of this kind of camera butchery:
The next two pictures are a before and after example of Zeiss bump removal from a back as this process is practiced here. These pictures illustrate a typical back and the type of results that can be expected provided the leather is in good condition and the bumps are of moderate size.
If the bumps are large the leather can be permanently deformed and there will a mark remaining in the area where the bump was due to changes to the leather texture caused by the pressure caused by the bump growth. If the bumps are extremely large a small depression can remain where the bump was. This is caused by the consummation of the leather in the bump material.
In some cases the leather is in such poor condition it is not possible to remove it from the back. In this situation the only remedy is removal of the leather followed by leather replacement.
Many people have inquired about the availability of cases for their Contax cameras. Unfortunately the old cases are over 50 years old, and the leather they are made of has lost most of its strength. These older cases tend to look good because they've been stored for a long time, but once they're put into use they tend to quickly split and fall apart at the seams. There are almost no original Contax cases available that are serviceable for regular use today. There is only one manufacturer of new cases for classic Contax cameras. These cases are hand made of the finest leather and will last a very long time. These cases are made for me specially to order for me by the finest and most experienced camera case maker in Japan. These cases are made specifically for each model and are not "generic". The are made of double thick leather that will easily last a lifetime and are hand made. I have a small stock of black and brown cases available for the Contax I, II, III, IIa and IIIa models. Both full and half cases are available and each comes with a strap included. Here's a copy of a new half case on a Contax IIa:
If you would like a new case for your Contax I, II, III, IIa or IIIa please contact me using this link: Mail To Henry Scherer
It is possible to recover a camera with new leather completely or to replace individual front or bach panels individually. Recently a source of leather having quality and appearance equal to the original Zeiss leather has become available and can be used to completely or partially recover your Contax. Special embossing stamps and machines have been obtained so that the back leather can be permanently and deeply embossed with the original Zeiss Ikon Stamp that is an exact duplicate of the original. It is even possible to personalize your camera by stamping your name in 23K Gold or Silver into the leather below the stamp.. Here are pictures of a recovered Contax IIa Camera back, a close up of the Zeiss Ikon Stamp and the embossing stamp used to put the Zeiss Ikon symbol into the leather:
Here's a closup of leather that has been recently stamped with a Zeiss Stamp:
This is a picture of the custom stamp used to apply the logos:
To apply the Zeiss Ikon or personilization stamps to the leather a Military Model Kingsley Hot Stamp machine is use. This is the same machine used today by the U.S. Military services to stamp names and badges onto flight jackets and other leather goods designated to receive a lot of hard wear: