How long is a roll of film?

Discussion in 'Black and White' started by stuart_todd, Feb 21, 2003.

  1. Right, this may be a stupid question, but what is the length of 24
    and 36 exposure rolls of film.

    The reason why is I want to see up a cash box next to my bulk
    loaders, so every time I roll up some film, I just put however much
    spare change of film I've used into the box and when it comes to buy
    a new bulk roll I will not have to whine about the cost.


    Stu :)
     
  2. 3ft/5ft or so.
     
  3. It's about 38mm per frame. If you allow four frames
    per roll for leader/trailer that gives 28*38mm = 1064mm
    for 24 exp, and 40*38mm = 1520mm for 36 exp. That's
    just a hair under 5 feet for a 36 exposure roll, and
    about three and a half feet for a 24 exp roll.
    <p>
    Another way of looking at the accounting is to note
    that a 100ft roll holds about 750 exposures in a bulk
    film back. So every time your bulk loader's frame counter
    clicks, whether it's for a "real" frame or for a leader/trailer
    frame, you've used around 1/750 the price of a 100ft roll.
     
  4. Don't forget that a bulk film loader fogs a bit of film at the end of each roll too. 5 1/2 feet to be safe! I find it easier and faster to just go in the darkroom, stretch out my arms, tear the film off the roll, tape and wind it on the spool and then assemble the cassette. After enough experience you'll learn just how far to extend your arms. Yes I have two bulk film loaders! They're a pain in the butt to use.
     
  5. Stu: I usually get about 19 36-exp. rolls and a bit left over out of a 100 ft. roll - so it's in the ballpark of 5-5.5 feet. I roll out 40 'clicks' worth after closing the light-proof hatch.
     
  6. Sometimes a roll lasts me all month long.
     
  7. Righto, thanks very much everyone for that. The going rate in now $0.12NZ a 'click' for FP4+.

    I find bulk loaders great and cheap. The only two issues I've had have been with auto wind on the Canon EOS series and storing it in the fridge (the length remaining dial froze up). And dust contamination hasn't appended yet (touch wood), though I do give it the blower brush treatment every time I use it and it does live in my sealed paper draw.

    Stu :)

    And roll lasts you a month Lex? Roll of what, bread?, tape?, wire?, roll in the hay??? Surely you don't mean film, not in this forum... :p
     
  8. My Watson 100 uses 40 frames per 36 exp roll
     
  9. I have some interesting data. All my use of Kodak bulk film has given me 18+ rolls of 36 exposure, like 18 full rolls and one roll of 24-30 frames. All of my Fuji rolls give me 20 rolls + 4-6 frames. This is from doing 3-4 bulk rolls (kodak)a month for 7 years at a newspaper and now doing 50+ rolls (fuji) and 10+ rolls (kodak) now on my own for 5+ years. Always the same, Kodak 18 + and Fuji a perfect 20. Same bulk loaders, same amount of clicks, same length of film, same amount of exposures including fogged section. I think Fuji feet is longer than Kodak feet.
     
  10. 100 feet of film is equal to 1200 inches.<BR><BR>35mm pitch is 0.1866" (short pitch)per ANSI PH22.93-1980<BR><BR>There are 8 sprocket holes in a standard 24x36mm frame.<BR><BR>1200 inches/0.1866 inches/sprocket =6430.87 sprocket holes per 100 ft roll<BR><BR>6430.87 sprockets//8 sprockets/frame = 803.86 frames <BR><BR>40 frames= one 36 exp roll with my Watson 100 bulk loader.<BR><BR>803.86/40= 20.09 rolls<BR><BR>I have gotten 20 rolls of 36 exp Kodak film for many decades; this is also the number in the Kodak literature from the 1970's and 1960's. <BR><BR>If you get short rolls; contact Kodak. <BR><BR>The numbers I remember from movie stuff is to remember 6400 hole/100 feet. (easy to remember!) <BR><BR>For 35mm cameras; there is 4 holes/frame; thus there are 1600 frames roughly/100 feet.<BR><BR>At 64 frames/second; this is only 25 seconds!<BR><BR>At 24 fps (sound); this is 1600/24= about 67 seconds. <BR><BR>At the ancient 16 fps; this is 100 seconds of filming<BR><BR>Many cameras hold 400 feet; thus this is 6400 frames; or about 4 minutes; when one considers the scrap due to film loading the camera's film gate and looping.
     
  11. Go buy cheap film, pull it apart and measure it. No calculation required!
     
  12. I second the "pull it out and measure it" technique. I had an old TMX400 roll from a couple years ago sitting around, and rather than kill a pint of fixer or get some result that differs from my typical triX, I just killed the TMX400 and sacrificed it to the god of darkroom reference tools.
     
  13. Why waisting a roll of good stuff ? Just measure it when it's processed. Film don't shrink in the process.

    Kris.
     
  14. Why does everyone roll 36's.
    You can get about 45 frames safely in a canister. Therefore, you need about fifty per roll, and that gets you 750/50=15rolls. So, you have 15x45=675 rather than 18x36=648. Thats an extra roll!
    Also, If you have a changing bag, or a darkroom, do it in the dark and spare yourself 2 frames per roll. That gets you 705 frames my way.
    For black and white this might be false economy. Since you want to swap out rolls, change ISO, or want to process it before your done with 45. And because B&W is cheep.
    But with slide film, this really makes a difference, since the rolls are more than 100 bucks.
     
  15. Dunno 'bout other folks, but when I roll my own it's usually *less* than 24 exposures. Sometimes for specific sessions I need only a dozen frames.

    Sometimes I didn't even use a bulk loader. I'd just stretch out enough Tri-X to reach from the middle of my chest to the tip of my hand, and roll it up with my fingers in the dark. Usually worked out to a little more than 12 exposures, including room for the leader.
     

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