Re: 120 or 220

[Paul Talbot <ptww@xxxxxxxxx>]

Lme Kbee wrote:
 
> I have noticed some people talking about 220 film.
> Even though I have been taking pictures for almost 20
> years, it has mainly been 35mm.  What is the
> difference between 120 and 220 film?

There are two differences:

  - 220 is twice as long as 120 (24 6x6 frames vs 12)
  - 120 has a paper backing the entire length of the
    roll; 220 has only a paper leader at the beginning
    and end of the roll (otherwise it would not fit on
    the spool, which is the same size as the 120 spool)

> In the context
> of using the Sputnik would help me visualize it.

Generally, 220 should only be used in cameras that
are designed to accept it.  As I understand it, two
specific camera features are "required" to accommodate
220 film:

 - Setting of the film pressure plate such that the
   220 film, sans paper backing, is held at the proper
   place for correct focus.  In theory, 120 film with
   paper backing would ordinarily be a bit closer to
   the film plane than would 220 bare film.  Whether
   the difference is real or not is subject to some
   debate.  (The method of holding the film at the film
   plane should also avoid scratching the bare back of
   the 220 film.)
 - A method of gauging film advance other than the
   "red window" used for 120 film cameras.  Light
   coming through the red window would fog 220 film,
   and without a paper backing there would be no numbers
   to read through the red window anyway.

The Sputnik does not have either of the "required" features.
220 film is thus generally considered unsuitable for use in
a Sputnik.  I had bought 10 rolls of stale-dated 220 after
being told by a pro lab that the *only* difference between
220 and 120 was the film length (no mention of the paper
backing).  Rather than throw the film away, I started working
on ways to use it in my Sputnik.  The technique is not quite
perfect, but it does work (provided some light scratching
of the back side of the film is not fatal to your particular
application).

Paul Talbot