35mm and Medium Format 70mm Film Conversion

by Rolland Elliot

I managed to successfully split some 70mm Kodak Aerographic Black & White film and some of the new 70mm Kodak Aerographic Color IR film straight down the middle. I used a simple apparatus made out of three pieces of wood. It is basically a U shaped trough made out of three pieces of wood and a Xacto razor blade in the middle. A frontal view is shown below: I lined the bottom piece of wood with some 100% cotton flannel cloth to prevent the wood from scratching the emulsion. And I put a Xacto razor blade (pointing down) in the middle located 35mm away from each side wall of wood.

I used the setup below in a darkroom by sliding a piece of 70mm film across the razor blade. After the initial cut was started I put a piece of 70mm wide 1 inch tall piece of styrafoam (this piece of styrafoam was also covered with some flannel material and had a small hole cut into it so it would fit over the razor blade) ontop of the film so that the film would lie very flat and even across the bottom. After putting on a pair of cotton gloves I pulled the film through the trough (in a smooth and even manner) as the razor blade neatly cut the roll into two even pieces.

                <-------70mm wide----->

                |                     |
                |                     |
                |                     |
                |                     |
           Wood |                     |Wood
                |                     |
                |                     |
                |   XActo Razor Blade |
                |___________|_________|
                 Wood

Each piece of wood was about 0.3 meters long and a couple of centimeters thick. You have to be very percise when making this wooden trough. Make sure the trough is exactly as wide as your 70mm film and make sure the razor blade is very sharp and located in the middle of the trough. To get the dimensions as precise as possible I used an acutal piece of 70mm film to space the trough's walls and I used two strips of 35mm film side by side to percisely locate where the razor blade should be put in.

I would suggest practicing cutting the film in half with a short strip of 70mm film in the day light before trying it in total darkness. This simple machine makes pretty accurate cuts, but the width of the film does vary a little. About + or - 0.5mm. This can be a problem depending on what kind of bulk film loading cassetts you are using. Some cassete spools are exactly 35mm across and this can cause problems because the film will squeeze into the space, but there will be a lot of friction and buckling and wrinkling of the film may occur when you advance or rewind yourfilm.

To wind up my color IR film I used some old Kodak TMZ cassete spools, because they were slightly wider than the bulk casette spools I had. When I loaded the B&W IR film I used casette spools that had one end of the spool broken off. The bulk casette was no longer light tight but I always load HIE in total darkness anyways so it doesn't really matter. I just used my hands to tear off one end of the casette spool. This leaves a slight ridge and the take up spool stays inside the metal snap casette. Here is a pic.

       __|___|__                 __|___|__
         |   |                     |   |
         |   |                     |   |
         |   |                     |   |
         |   |                     |   |
       __|___|__                   |___|
Regular Casette Spool         Casette spool with one end broken off.
Here are a few more tips:
  1. Practice the entire loading procedure in the daylight before trying it in complete darkness.
  2. Make sure your darkroom is absolutely light tight!
  3. Make sure your splitter has no dust or dirt in it before you turn off the lights. A single grain of sand could scratch your entire efforts.
  4. If you are in your darkroom and suddendly realize that you don't know which side of the film is the emulsion side just lick the film leader with your tounge and scratch it with your finger nails. The emulsion side will feel sticky and the film base side will remain smooth.
  5. Expect to be in the dark for a long time. It took me about 2 hours to bulk load 20 casettes.
  6. Be sure you have some kind of light tight container to put all of your bulk loaded IR film inside of before you open it up.
  7. Your film will only have perforations on one side, so make sure your camera can advance and rewind film of this nature. And make sure that when you bulk load your film the perforations are in the correct location. My Nikon N90s can handle film perforated only on one side, but the perforations must be on the bottom. In order for the film to feed through properly I also had to cut off the 4 top teeth of the frame counter spool. Don't cut off the bottom 4 teeth or the camera won't be able to advance the film and you'll have to send the camera in to get fixed.
  8. Realize that you will probably have to develop this film yourself by hand since it only has perforations on one side.

Good luck to anyone who tries this.

I have shot two rolls of my bulk loaded 70mm Color IR film and the slides look great. I developed the film myself in E-6 processing. So there is proof that the 70mm AR-5 film is E-6 compatable!

A similar apparatus could be used to cut down 70mm film to Medium format size with performations on one side. The only difference is that instead of puttng the Xacto blade in the middle, you have to put it 61.5mm away from one side. If you don't feel up the task I actually sell 120 and 220 B&W and Color film you can contact me for details.

I actually researched getting the 70mm film split down the middle by a professional converting company before making my own splitter. The estimated cost of splitting the film was variable but I got estimates from $100 to $200 US for splitting one roll of 100 foot long 70mm film. The price decreases a lot if you have more than one roll split. I was going to send in a roll, but none of the companies I talked to seemed very enthusiastic about splitting the film and their film width tolerances weren't very exacting. I've heard in the past that companies like Seattle Film Works and Signature Film make their 35mm film out of old 70mm movie film, by splitting it down the middle. If someone could find out what converting company does this than you might get them to split AND perforate a roll of 70mm film.

by Rolland Elliot

 

If you would like to buy 120 and 220 IR film services from Rolland, cost and contact details are as given below. This film is cut down from 70mm film and therefore has sprocket holes on one side that protrude about 1 to 2 mm into the bottom edge of the negative/positive.

120 EIR or HIE $20 a roll
220 EIR or HIE $25 a roll
Shipping is $4 per order

Address:

Rolland R. Elliott
25 D Janet Circle
Bridgeport, CT 06606
Tel. (203) 371-8412



CoCam has not tried this methd nor used Rolland's commercial solution, however if you try this film splitting method yourself or have successfully used some of Rolland's ready rolled film please let me know.


Last Updated: Thursday, November 4, 1999

Part of the Infrared FAQ located at CoCam Photo.