Information - pressure plate for Super 8

Hasenheide 9
D - 10967 Berlin


+49 (0)30 691 7036
+49 (0)30 693 0321

Switch to German

Prices in Euro plus 19% VAT (only for private EU-customers) plus shipping costs

- Prices from Jan. ‘07 -


Improved Running Qualities for the Super 8 Film Cartridge

Certain shortcomings of the Kodak Super 8 cartridges that can be purchased have challenged quite a few technically experienced users to have a go at changing one thing or the other. Everybody agrees that there is only one kind of acceptable running qualities: those of the double Super 8 film camera. There, a film stock loop is formed by one or two sprocket drums. The moving pin simply needs to accelerate the small and constant amount of that piece of film stock. It's quite evident that this is an indispensable prerequisite for a high-quality picture steadiness. Thus, Weinberger's famous Super 8 camera which is capable of shooting up to 250 frames per second, could only be achieved by pulling a bit of film stock out of the cartridge and having a forward and a backward winding sprocket drum form a film loop. The sprocket drum pulls the film stock out of the cartridge and feeds it back in one continuous motion. Here as well, the moving pin has to accelerate just the short piece of film stock in the loop. Nevertheless, this still wasn't enough to ensure a good picture steadiness at the highest speeds. To this end, a checking pin had to be introduced.

However, we usually don't use 250 frames per second very often, but even at 24 frames per second the picture steadiness is frequently less than poor, not to mention the quality of the so-called 50 fps slow motion. I think the fact that the picture steadiness in many cases still turns out to be usable is a kind of miracle. It is absolutely necessary to jolt the cartridge to loosen sticky windings before inserting it. The film cartridge should be a precision-made device. I have heard of a company that had developed a refillable cartridge with better running properties. Unfortunately, that device was never offered for purchase. Also, as I was told, Kodak has never agreed to refilling that cartridge with new K40 film stock. But, as we still have to use the Super 8 cartridge, we should be glad and grateful for every successful attempt to improve the running properties of it. If success was indeed attained, then you can be assured that this was the result not only of investing a whole lot of work and thought based on expert knowledge, but also of bearing personal financial burdens. So, there is really no reason to look down upon people who become obsessed with this kind of task.

A person of this nature is Mr Klose who, in fact, managed to improve the running qualities of the Super 8 cartridge. In order to explain how Mr. Klose won me over I need to go back a little: I had to shoot some takes from a video display. Unfortunately, the sensitivity of the K40 film wasn't good enough, so I had to use the Ektachrome 7240 which is more sensitive. When this film came back from processing, it showed many weird double exposures of single frames that had been caused by faulty transport. When I talked to Mr. Draser of the Andec-Filmtechnik company I learned that this is a known phenomenon that occurs in many cameras when used with the Ektachrome 7240, including my camera, a Nizo 6056. Only well adjusted cameras will work, but it must be tested out. As I have a Beaulieu 4008 ZM 4, I immediately set out to try again. This new attempt was not very successful either, which was partly due to exposure variations caused by the camera not being able to keep the speed of 25 frames per second. Thus, I had to use my Nizo camera as it can be set precisely to 25 frames per second, which rids the film of the brightness variations that annoyed me. That's how I ended up being restricted to using Mr Klose's method. Curiously enough, his method is just a matter of inserting a small metal plate behind the film on top of the cartridge's plastic pressure plate. Should you think that's all? It is! With the pressure plate in place, the film now runs smoothly through the camera at low noise.

However, it would be a big mistake to think that the only thing needed to solve the problem is to simply push a small strip of metal between the film and the plastic pressure plate of the cartridge. As you can see in the other figures, the plate features quite a complex shape. In addition, its thickness is also critical. Mr Klose had to manufacture several plates with thicknesses differing by just one thousandth of a millimeter from one another, before he achieved satisfactory results. The side exposed to the film had to be smoothly polished and, what's more, hard-chrome plated. So you are obviously well-advised to remove the plate after your shooting; if you don't, the Kodak processing people will surely keep it. I am using it in all my cartridges, both in regular K40 and in 60m sound film stock. The results are excellent: the variations in sharpness are gone because the film can't get off track, and the picture steadiness is by far better. If you wish to work with the Ektachrome 7240, you simply can't do it without this additional pressure plate.

As I see it, the Ektachrome 7240 has become significantly sharper. Moreover, it seems to have a finer grain now. In the past, I used to use it only in emergency situations, when the sensitivity of the K40 wasn't sufficient. Meanwhile, its grain has become so fine that its sharpness is better than that of the old Ektachrome 160. I had asked Mr Draser to examine the film and to send me some more Ektachrome 7240 filmstock if the picture steadiness turned out to be good. The Ektachrome 7240 presents a real alternative to the K40. If you now think you wouldn't have any problems using a Beaulieu camera you are wrong again. You can't avoid having exposure variations when using a Beaulieu camera because its exposure time is just too short. For clarification, I should say that I work with a 100 Hz monitor. All the trouble you can experience when using regular K40 cartridges also occurs when using Beaulieu cameras. And don't forget the film jams that can occur so that even Mr Klose's pressure plate can't do a lot about it. However, in my opinion, such a faulty cartridge should be sent back to Kodak, complete with a letter of complaint.               

 Karl H. Leonhardt

This article is published in the following German filmmakers magazin ‘Schmalfilm’ issue March/April 2002.
Publishing house Schiele & Schön, Berlin - Germany.
(with kindly permission of the author
Karl H. Leonhardt)





Prices in Euro plus 19% VAT (only for private EU-customers) plus shipping costs



Site Statistics / Welcome Page
This page has been generated on Juli 03, 2007