These are archived discussions from the Usenet, which discuss reperforating motion picture filmstock. To do more research, I suggest using Google and doing a search of "groups" (choose "groups" in the main menu, then select).

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Hello all:
Just a question that's been bugging me for quite a while:
Does anyone know where I can get a hold of an 8mm perforating machine? I
know they exist, I just have always hit a wall when I've previously put my
feelers out there for one. I'm talking about a machine that will
double-perforate 16mm film stock so I can spool it on to an old 8mm reel
and shoot it on an old 8mm camera (Bolex P1). I've been wanting to shoot
7363 Hi-Con as well as a lot of the Vision color stocks in 8mm and this
way seems like the only way to do it.
If there's anyone out there who can give me a good idea about where I
could maybe start looking I would be entirely grateful.

Thanks much,
Hans Michaud

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>Yes, I buy these stocks on a regular basis...I just wanted to be able to
>try some of the other, non-reversal stocks in reg 8mm!
>Take care,
>Hans

---> Try Larry Pearce in England. He used to offer a reperforating service for
perforation of 16mm filmstocks to Double 8mm. He is now working out of his
home on a more reduced workload basis.
L.G. PEARCE
Lelant house
Royston Grove, Hatch End,
Pinner, Middlesex
ENGLAND, U.K. HA5 4HD
Tel: 0181 421 3666
Ringing from the USA dial 011-44-181-421-3666

---> Many of the film slitting and reperforation machines were made by Buhl in
Germany and the punch dies have to be replaced when worn. There is quite a bit
involved in maintaining such a machine so that it remains accurate.
Reperforation of 16mm filmstock which is already either single or double
perforated, will have a slightly different pitch. This will sometimes cause
some vertical unsteadiness upon projection. However...IF you use a camera and
projector which have the same pull down rate, then the film will project quite
steady. This was one of the problems over the years of the Double 8mm format
(Regular 8mm) since many manufacturers varied from one another as to their
camera and projector pull-down rates. Often, it's not a problem,
however...Larry Pearce relayed to me and also via a projection demonstration
and critical film examination when I was over in England, that there is
definitely a pitch variation. Many 8mm users don't seem to mind it...and the
dedicated ones tend to use matching cameras and projectors so the pull-down
rate is the same.

Best wishes,
Martin W. Baumgarten

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Here is a series of communications regarding a film perforator that could be
used to convert standard 16mm film perfs to 0.15" pitch suitable for use in
double 8mm movie cameras. So that everyone in this newsgroup can provide
their feedback, I'm reposting it here...

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Hans M

Hello all:
Has anyone here heard of an 8mm perforating machine (double-perfs 16mm film
which results in Regular 8mm film stock) out there and how one would go
about trying to get one? I\'d love to try my hand at shooting some of the
non-camera stocks (7363 HiCon) or Vision stocks (Kodak\'s new color neg line
of 16mm/35mm films) in my Bolex P1 (Reg 8mm camera). I\'I've been searching
hi and low for this...does anyone know if this thing exists and if it can be
had?

Thanks in advance,
Hans M
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Phillip

Hi Hans,
I'll be honest with you....I haven't heard of such a device, however, it
doesn't mean that there isn't one out there.

I would get a hold of Martin at Plattsburgh Photo, (you can find him on the
8mm Film Format Metadirectory). He is always messing around with the various
formats. As of right now, he's trying to bring sound film back!

Good Luck
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Jim M

Interesting idea. I've considered making such a device. The difference in
Reg 8mm to Reg 16mm filmstock is the 16mm perfs are every 0.3 inches and Reg
8mm adds an extra perf (one between each 16mm perf so-to-speak) for a pitch
of 0.15mm (EDITING NOTE: hmmmm...I meant to say 0.15 inches here).

I envisioned a simple set of double rollers - one with raised perfs and the
other with the square mating hole - of hardened steel with the punch
machined to the exact same 0.15 inch pitch with the exact dimensions. The
"hole" roller would have the holes completely through the roller to punch
the perfs completely through.

The rollers would have to be fabricated from extremely hard steel and must
mate with the punch in a cutting/shearing action like a paper hole punch
(but much more serious!). The middle of each roller would need to be
recessed so as to leave the exposing area of the film untouched so not to
scratch or mar the emulsion surface.

In making such a device, the pitch dimensions would require extreme
accuracy. The only problem with this device that I could foresee is that
film stock may expand and contract with temperature which could cause the
device to go "off" the initial guide perfs of the original 16mm stock. This
could mess up an expensive roll of film. But, with care and proper guiding,
it should work.

One major drawback...you would have to have a lot of demand for such a
device to make the potential sale of them enough offset the fabrication
costs. Anyone interested...e-mail me...and I try to obtain some preliminary
pricing for making such a device with my local machinists.

:-)
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Hans M

Jim:
I'm interested...it's a good idea, a group of people going in on this
together. Where would the actual machine reside, though? Would it get
shipped to each other's places? Would one person hold it and everyone else
send him/her their filmstock to get perfed?
Let me know what you think.

Hans
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Jim M

Thanks for the response, Hans. What I was thinking, if enough people are
interested, is to draw up the plans to have a qualified machinist to
estimate from. Then, take the number of interested parties (n) + 1 (for
me...of course...got to recover my development time by getting a free unit!)
by the cost to produce n + 1 units and divide by n to distribute the cost.

Probably will have to make initial unit as a single run to check
feasibility, design, etc..., to insure units success. Then, the n units
should be able to be produced at a discount for quantity. I think this
should make an interesting project! Anyone else interested. So far I've had
2 responses. Please, if responding by email, include a copy to this forum so
we can see where this may be going. How about regular 8mm film at 16mm film
prices. This could resurrect regular 8mm even more than Kodak has allowed
with their special run perfing quantities.

Jim M

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Roller perforators don't work. The idea was discarded in the 1920's.
Perforation works by step and repeat.

Larry Pearce of LGP CIne in Wembley, England used to have a machine for
reperforating 16mm to 8mm. He might still have. He did some for me in the
1970's. I don't have a telephone number.

SS
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Folks,

Reperforating 16mm film to 8mm has been tried and accomplished with
limited success over the last 50 years. The problem that has never really
been overcome is that fact that the pitch on 16mm film varies from
manufacturer to manfacturer and even from a given manufacturer will vary
from batch to batch depending on various variables. My last communication
from Larry Pearce was that he no longer reperforates 16mm film because he
has so many problems with the process. The concept seems simple but is
difficult to realize.

Any reperforator would have to actually measure the pitch on the 16mm film
to be reperforated and then calculate the correct 8mm pitch for each new
perforation punched.

It is probabily more cost effective to special order the film from
Kodak. I can order most 16mm emulsions in 8mm from Kodak. The cost is
around $2500.00 per order. If interest is high enough, I would be willing
place an order.

John Schwind
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Thanks for your insight, Steve. Can you expand as to why roller
perforators don't work? Sure would not want to repeat a bad design! Also,
is the machine Larry Pearce has an expensive machine to reproduce?

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Because how ever you design it, the cutting edge goes in/out at an angle and thus
doesn't cut cleanly. You need a fairly deep hole and a sharp blade to make sure
that you have cleared the part you are trying to cut. (Insert Florida joke) .

Secondly, they are liable to slip inaccuracies as there isn't a ready method of
guiding the film through positively. In a punch and repeat you can use the just
cut perfs as a guide for the next cut.

Edison used a step and repeat hand cutter. Lumiere used a rotory cutter. The
edison (or at least something like it) perforation won. If you're wondering,
Lumiere's were round.

SS
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