Jump to content


Photo

perforation pitch


  • Please log in to reply
7 replies to this topic

#1 PKM

PKM

    New

  • Basic Members
  • Pip
  • 6 posts
  • Cinematographer

Posted 13 May 2005 - 05:46 PM

Hi guys,

Does Kodak 35mm black and white motion picture negative film have a different perforation pitch from Kodak 35mm colour motion picture negative film? I recently bought some of each from a short ends distributor, and the colour runs through my camera (an Arri IIC) fine, while the B&W perforations seem to continuously tear, and the film loses its correct size loop within the camera. The two films would seem to both be new, originating from approximately early this year.

The perforations drift by the equivalent of one full perforation over the course of about 6 feet of film (when you hold a strip of the colour against a strip of B &W)

Does anyone have any suggestions / explanations?

Peter
  • 0

#2 Dominic Case

Dominic Case
  • Basic Members
  • PipPipPipPip
  • 1357 posts
  • Other
  • Sydney Australia

Posted 14 May 2005 - 02:58 AM

One perf in six feet is about 0.3% difference. That's a little more than the difference between neg pitch (0.1866") and pos pitch (0.1870"). But there's no reason for the difference unless you have been sold some stock with non-standard perforations. Normally b/w and colour are the same. The label on the can (if it's original) should show you the pitch - look for one of those two numbers.

People have sometimes reported difficulties running some types of b/w neg in some cameras - but it seems to be more to do with the built-in lubrication of the film surface that the pitch of the stock.
  • 0

#3 Adam Frisch FSF

Adam Frisch FSF
  • Sustaining Members
  • 2009 posts
  • Cinematographer
  • Los Angeles, USA

Posted 14 May 2005 - 08:28 AM

Can film shrink?
  • 0

#4 John Pytlak RIP

John Pytlak RIP

    (deceased)

  • Sustaining Members
  • 3499 posts
  • Industry Rep
  • Rochester, NY 14650-1922

Posted 14 May 2005 - 10:17 AM

Can film shrink?

<{POST_SNAPBACK}>


Yes, triacetate film can shrink, but it usually takes many years.
  • 0

#5 PKM

PKM

    New

  • Basic Members
  • Pip
  • 6 posts
  • Cinematographer

Posted 15 May 2005 - 07:38 AM

Yes, triacetate film can shrink, but it usually takes many years.

<{POST_SNAPBACK}>


Hi John,

If I did get Kodak B &W (5222) and Kodak Colour (5245) 35mm films from a short ends distributor, and both would seem to have originated from earlier this year, would it be possible that the perforations of one, relative to the other, drift by the equivalent of one full perforation over the course of about 6 feet of film? And again, when I run each roll through - the colour one works, the B & W clearly tears and loses its loop, then back to the colour one, and it works, and then back to the B & W one, and it tears and loses its loop - does this seem possible? I know that on newer cameras than the Arri IIC there are more sophisticated pitch control adjustments that can be made, which are done to make the camera quieter - but should any type of stock completely not run through the camera?

Peter
  • 0

#6 John Pytlak RIP

John Pytlak RIP

    (deceased)

  • Sustaining Members
  • 3499 posts
  • Industry Rep
  • Rochester, NY 14650-1922

Posted 15 May 2005 - 09:31 PM

If film were kept in adverse conditions (e.g., hot), it could have shrunk at a faster rate. Unfortunately, short end vendors are at the mercy of their sources, who may not have stored the film properly, or mixed in some really old stock.
  • 0

#7 Nate Downes

Nate Downes
  • Basic Members
  • PipPipPipPip
  • 1638 posts
  • Florida, USA

Posted 16 May 2005 - 07:57 AM

I just shot some old stock last weekend, and it's shrunk by around 0.2% at 7 years of age. As I was shooting it soly to test out the camera, no big deal to me. But that is the break of using older filmstock.
  • 0

#8 Laurent Andrieux

Laurent Andrieux
  • Sustaining Members
  • 1527 posts
  • Cinematographer
  • France

Posted 19 May 2005 - 08:07 PM

Even if 1 perf over 6 feet gives a figure of 0.3 %, I don't like that, and wouldn't be astonished if it was linked to the cause of your troubles...

John doesn't take account the fact that some stock can have a manufacturing problem, sometimes.

I've had problems with non regular perf on some 35 mm stock once, not enough to occure what you describe, but just enough for having a very bad registration pin test (a big ad that was going telecine + digital post prod !).

Did you do this test with your stock, BTW ?

Just to reasure John... No, it was not kodak stock ! and what is funny is that the ad's client was... the stock manufacturer ! ;)
  • 0


Visual Products

Glidecam

Broadcast Solutions Inc

Paralinx LLC

Wooden Camera

Aerial Filmworks

rebotnix Technologies

Gamma Ray Digital Inc

Technodolly

Willys Widgets

CineTape

CineLab

Ritter Battery

Tai Audio

Metropolis Post

Media Blackout - Custom Cables and AKS

FJS International, LLC

Abel Cine

Rig Wheels Passport

Opal

The Slider

Rig Wheels Passport

Paralinx LLC

CineTape

Broadcast Solutions Inc

Media Blackout - Custom Cables and AKS

Visual Products

Ritter Battery

FJS International, LLC

Gamma Ray Digital Inc

Willys Widgets

Wooden Camera

Abel Cine

Technodolly

rebotnix Technologies

Opal

The Slider

Aerial Filmworks

CineLab

Metropolis Post

Tai Audio

Glidecam