Do Russian cameras run B&H or KS perforated film? What's the difference?

Konvas 2M with 17ep motor
Konvas 2M with 17ep motor
B&H perforated film versus KS perforated film goes back to the early years of film. Without getting into the politics of it all, there were two types of 35mm films made: one type, made by Bell & Howell, was adopted by most of the world for use as the negative film in 35mm cinema cameras. The other type, called "Kodak Standard" (KS for short), was mainly used in still photography and in answer prints for use in 35mm projectors (in theaters). It seems that KS perfs are less prone to tear, but don't register as well as B&H perfs, so having two different kind of perforations was a good solution. Due to their use in answer prints (aka positive prints), KS perf is sometimes called "positive perf" film. Note that 16mm and 65/70mm Motion Picture cameras and film only have one kind of perforation.

For some unknown reason, the members of the former Soviet Union decided to stick with KS perfs in many models of their 35mm cinema cameras - but these are only the models that have registration pins. Luckily, due to the designs of the Konvas (not having a registration pin), it will run both B&H and KS perforated films without a problem (that means that there are no needs for modifications).

A Kinor 35C, 35H, and 35-PII (in other words, the Kinor 35mm models), on the other hand, will need to be converted to run B&H perforated film (cost is usually around $500 US). For other cameras, you will probably want to ask the Cinema discussion list. If you find that you're one of the rare ones with a Konvas that actually has a registration pin, please post to the discussion list on what to do (the registration pinned Konvas are a rarity).

35mm Kinor 75mm
35mm Kinor 75mm
In a post on Friday, 12 March 2009 at 01:08:26 EDT, Peter Haas added the following:

A BH registration pin can be made to much tighter tolerances than can a KS registration pin.

As Western producers typically used their pin-registered cameras interchangeably between production and process/sfx work, one camera pin type was needed, and it was NOT the KS pin.

One perf would have been OK had KS registration pins be made to the same degree of precision as was possible for BH pins. But, that was not the case.

PLUS ... KS pins are taller than BH, meaning running KS-perfed film through a BH movement WILL WORK, but the BH registration pin has nothing to work against, hence there will be no consistent vertical registration.

And, as Mitchell and similar movements do not depend on the application of side pressure for lateral registration, but on the difference between the "big pin" and the "little pin", there is no consistent horizontal registration when running KS negative through a BH pin-registered movement.

There is also DH perfs, which combine the shape of a KS perf, but the pin height of a BH pin. Used almost exclusively in the lab for dupes and effects work.

Note that CS perfs also have the same pin height as BH pins (hence the same height as DH perfs) ... reduces weave when contact printing CinemaScope prints from the composited negative, which was the U.S. practice until about 1969.

Bottom line is the KS pins are the odd-balls.

KS perfs tear less than BH and DH and CS perfs tear less than KS perfs.

The Soviets adopted the SMPE proposed standard. The Western producers ignored the SMPE proposed standard and stuck with BH and DH for their work, because these provided better registration.

When it came time to re-engineer the processes for wide screen, particularly "flat wide screen", Western producers still retained KS and DH because of the requirements for tighter registration, most particularly with FWS.

In a seperate post on Friday, 12 March 2009 at 04:12:37 EDT, H.W Stone added the following:

K was adopted as the accepted designation for squared corner Kinoscope designs, the Kodak Standard projection format being an improvement, but a much later improvement. The international large print, single letter P was used to designate the modified, newer perforation because KS turns out to be obscene in some languages, and single letters made sense in avoiding confusion.

BH perforation was adopted in the days when film stocks were not nearly as tough as today, and was a great improvement that went through several revisions, but what we see now is the final result of the standardization of four types of K stock and two B stocks into a single K and single B production-- but instead of BH they used N for international designations because it avoided confusion between a B perf and the winds-- A wind or B wind, emulsion out or emulsion inward.

There is an entire thread dedicated to this discussion in the Archives starting on the 12th of March, 2009, titled, "35mm film for still cameras into Konvas Mag?"

You will also want to look at Kodak's page: Why Do Sound Negative Films Use Kodak Standard Perforations? And this page on Film Packaging Components. Don't forget to look at Fujifilm's page: F-CI Intermediate Film (especially towards the bottom).