What kind of 16mm film stock has 3 sprockets for every 2 sprockets of regular 16mm?

[Daniel D. Teoli Jr.]

Someone used a piece of raw, undeveloped 16mm film stock as leader on a reel of a 16mm silent film. The piece of film in question is double sprocket. (Each side has sprockets.) And it has 3 sprockets for every 2 standard 16mm sprockets. In other words, where the standard 16mm film has no sprocket, this film has a sprocket, and all sprockets on this film are evenly spaced.

What do they use this type of 16mm film for?

[Charles MacDonald]

if you mean with a sprocket hole in between every pair of what would be 16mm sprockets, you may be talking about "Regular 8"

regular 8 was exposed along one edge, and the roll turned over and then exposed on the other edge.  after processing the film was split down the middle and the two parts spliced together.  the holes were half the distance of 16mm sprockets so a total of 4 times the frames could be shot on each length of film.

most often provided in 33 ft rolls (25 use-able feet) on a special spool for Home movie cameras.  after processing the film was returned as a 50ft spliced length of 8mm film.

 

[Charles MacDonald]

if this does not make sense please post a picture of what you have

[Daniel D. Teoli Jr.]

Ok, will work on getting a photo. The 8mm could be a possibility, but don't know. The sprocket holes look to be the same size as regular 16mm. 

It will take some time to get it. I found it while organizing my 16mm film and don't remember which can it was from. Hopefully in a few days. 

 

[David Mullen ASC]

https://en.wikipedia.org/wiki/8_mm_film

[Dom Jaeger]

Yes it’s just the original 8mm gauge - Standard 8, or Double 8 - which is basically double perf 16mm film with twice as many perfs. After processing it usually gets split down the middle to make it 8mm wide. 
 

 

[Daniel D. Teoli Jr.]

Can't find the film in question. Spent half an hour looking, but it got buried back in the hoard. BUT...you are right about the 8mm. I took out an old 8mm reel and matched it up to 16mm. Same exact sprocket size as 16mm and same ratio as the missing film. 

As I was looking for the lost film, I noticed it was fairly common to use old, undeveloped 16mm film as leader. Never thought about it much before. But this was the first time in over a thousand reels I saw someone using uncut 8mm film as 16mm leader. 

Thanks for the help!

Edited February 13, 2022 by Daniel D. Teoli Jr.