Here is the method I use to cut 120 film down for use in 127 cameras - by Luke Taylor

I am offering a 3D printed cutting device on eBay (blue and yellow thing in the pictures) but any method to cut the roll will work.  My first device was nothing more than a shallow hole cut into a block and a utility knife blade screwed to the block.  The device has a recess in the yellow part to contain the end of the roll while the blue arm that houses a razor blade is lowered into the film.  Here are step by step instructions on how to use it.

With great care, it is possible to do steps 1 through 6 in subdued light.

Step 1: If you want to use the film in a 4x4cm camera that shows the film’s frame numbers in a red window, pay close attention to the roll orientation in the picture. This will preserve the 4cm frame numbers.  (The backing paper on 120 film has frame numbers for both 4 cm and 6 cm images; we want to use the 4cm frame numbers for 127 format). If you do not plan to use the film in a 4x4 camera that has a red window then it does not matter which end of the roll is cut off.

Step 2:  This picture shows the film roll in the recess hole in the yellow side of the cutter.  It is important to keep pressure on the roll as it is rotated to keep it bottomed out in this hole.  This will ensure the cut is even and at the correct depth.  It is also important that the rotation of the film is such that the drag of the blade is “tightening” the rolled film on the spool.  The picture shows this direction with a red arrow. 

Step 3: Rotate the film with one hand and apply moderate pressure downward on the blue cutter arm with the other.  Continue until the blade has cut through all of the film and backing paper.  You will notice the drag of the blade will increase when it contacts the plastic spool.  Do not attempt to cut off the spool; only the film and backing paper are to be cut.

Step 4 & 5:  Unspool a length of the backing paper until the “Start” marking is seen.  Be careful not to unspool too much paper - that will expose the film to light.  I use a big metal binder clip (as seen in Picture 5) to hold the remaining film on the spool while I prepare to cut off the excess paper.  Fold the backing paper in half lengthwise and make a diagonal cut.  This technique will ensure a very symmetrical “V” in the paper.  Bottoming out this “V” in the 127-spool slot will perfectly center the paper in the spool.  I would not attempt to cut any shape by “eye” because it won’t be centered well and will cause difficulty when loading to 127 spool.  The length is not very critical.  We are just trying to remove the excess amount so the completed spool diameter will not be too big.

Step 6: You can get the paper started on the 127 spool and clip it as well to prepare it for the transfer steps.

The remaining steps must be done in a darkroom or changing bag.

Step 7 & 8: In complete darkness roll the backing paper tightly onto the 127 spool until you feel the tape on the start of the film.  Carefully peel the tape off and save it (I just stick it to the back of my other hand).*

Step 9:  Carefully tuck the film into the partially rolled backing paper and continue to roll the film and backing paper onto the 127 spool.

Step 10 & 11:  While transferring be sure to allow slack between the 120 and 127 spool for the film and backing paper.  Because the 120 and 127 spools are different diameters, a buildup of excess film will happen.  I have been successful with letting go of the 120 spool once the 127 has a decent amount of material on it.  It may also be necessary to “tighten” the film on the 127 spool as you go to ensure it is fully seated on the new, smaller diameter spool.

Step 12:  When you’ve rolled to the end of the film, tape the film to the backing paper using the tape we saved from the beginning (Step 8).  This is also the time to mark the backing paper to indicate where the film is starting.  I use little stickers for this.

I am hoping this article will encourage more people to shoot images for the next 127 Day. 

*Note about Lomography film: I have found the tape they use to be INSANELY sticky. This has caused a lot of frustration when transferring the tape, FYI. 

- Luke Taylor