Film is Fine

First I examined several projectors to see which would be easiest to convert to Ultra-16.  I wanted a nice simple film path that would avoid the unnecessary sound drum.  I suppose one could  add a half-width stripe to U16,  but for my purposes I just need a machine that shows the format mute,  and  is kind to the image.   And it goes without saying that picture steadiness must be good.

I finally decided on a Bolex S311.  First I tested it thoroughly with pristine film to make sure there was no wear on the perforations.  I was pleased with the smooth sound of the transport,  sweeter in fact than my S321.   Now,  it must be said that the gates of Bolex projectors have to be set up perfectly.   Otherwise, in my experience,  transport problems can occur.   I didn’t  want to disrupt what the Bolex engineer  had achieved long ago,  so my first act was to mark the precise surroundings of the gate assembly with a scriber.

I now removed all the bolts around the gate assembly and laid it all down on a clear surface with plenty of daylight.  Next I dismantled the front pressure pad and carefully put aside the springs etc.  I knocked up a stand out of wood that could be clamped down,  and attached the rear gate plate with screws.  By examining a piece of Ultra-16  test film in the channel I was able to ascertain just how much metal had to be removed either side of the rear aperture.   Now with the aid of a magnifier I carefully filed it away.  I also removed some of the sides top and bottom to make a nice smooth channel for the film to pass.   If you do this I recommend taking frequent breaks as you don’t want to let that file slip and score somewhere else in the channel.  Afterwards I used very fine emery paper to smooth off the edges.

Next I turned my attention to the front gate pad.  Again I screwed it carefully to the wooden stand.   As it shows the actual area of the desired image great care must be taken to get the dimensions right.  

It was a bit tricky positioning the U16 film sample  to check my progress.  Eventually,  I was happy with the filing either side.  For my purposes I wanted the whole U16 image to appear on the screen,  so I did not provide a safety margin as projector gates normally have.  After  making sure the edges were smooth,  I  filed out two thin pieces of metal to form the top and bottom of the gate.  To the front side (facing the projection lens)  I very carefully Araldited on one of the pieces,  again checking it with the U16 film sample.   The other piece is held in place by a small length of wire that I glued on.   So it is able to be slid out and removed.  I did this because I intend to use the projector to assist in making cutting copies with a synched 16mm camera…  I can mark the film outside the U16 area for later conforming.   But this mask-removal option is not needed for normal U16 projection.  Lastly I painted the surfaces around the gate matt black.

All the above took me quite a long time.   I was not even sure  that the end result would be satisfactory.  And spending a day of one’s  life ruining a Bolex projector isn’t  a nice thought.  Mainly I was concerned if I had removed too much metal for the film to be held flat and firm in the gate,  and  whether scratching might occur near the edges of the image.   So it was with some trepidation  that I screwed the gate assembly together and replaced it on the projector  carefully in the marked position,  finally adjusting the hinge that carries the framing knob.    I threaded some film  and switched on.    All appears well !

But the conversion is only part done.  I must now turn my attention to the sprockets and rollers.  Anything that touches the U16 image must be removed.  I’ll let you know the result next time.