This is a picture of two rolls of Zeiss Ikon film dated 1947. Zeiss made film for its cameras and you can be absolutely certain that it was designed and made to provide the user with the best possible photographic experience available at that time. It's a shame Zeis does not make film today.
The occasional Super Ikonta gets sent here for an overhaul every now and then. It is not unusual for the owner to report film frame spacing problems and to ask for the camera to be adjusted to correct this problem. It is unfortunate that there is no possible internal camera adjustment to correct uneven or overlapping frame spacing. The reason for this is that the film advance mechanism contains no provision for adjustment. It's made up of metal gears and latches that are firmly anchored in place. It is possible to completely cut out the interlock in the camera so that frame spacing can be controlled manually and this is discussed later.
The main thing to understand about the Super Ikonta wind control mechanism is that it does not allow the same amount of rotation of the wind knob for each exposure. As film accumulates on the take up spool the spool effectively becomes larger. As the spool accumulates film less and less rotation is required to move a full frames length of film onto the takeup spool.
The Super Ikontas were designed to be used with a specific film having a very closely calibrated and controlled thickness. The reason for this is that as the film is wound up on the takeup spool the spool diameter increases and as the film accumulates on it less and less rotation of the spool is required to wind a frame length of film on it. Inside the Super Ikonta wind controller is a brass drum. This drum rotates as the film wind knob is rotated. Cut into the side of this drum are slits. After an exposure is made a spring loaded latch is pulled out of its slot in the drum, the wind mechanism is unlocked, and the wind knob is free to rotate. This latch falls into the next slot in line on this drum and locks the film advance mechanism when the film is wound to the next frame. The slits on this drum are cut closer together around the drum to compensate for the increasing diameter of the film take up spool as film accumulates on it.
Inside every Super Ikonta body is a marking to identify the film for which the camera was designed to be used. This marking is either in the form of a label, or it is sometimes embossed into the metal. These are always films made by Zeiss Ikon which are no longer available today. But these identifications go to show that Zeiss built the Super Ikontas to be used satisfactorily only with the films Zeiss made specifically for use with the camera and you can be sure these films were very precisely made.
Since the time the Super Ikontas were made the film available today has become thinner and so has its backing paper. This means that as the film accumulates on the take up spool the spool does not become as thick as the camera was originally designed to use. The result is that some of the film frames will overlap because at the start of the roll the allowed rotation of the take up spool is not enough to advance a full frames length of film.
There are three ways to compensate for this problem: