Who Decided 35mm Film Comes in 24 or 36 Exposures?

[Roger Hicks]

I think a proper length for 36 exposures, with Leica-type full leader trim, should be 1.64m.

Any particular reason for the extra 4cm?

Not being combative: just wondering about your source or reasoning.

Cheers,

R.

 

[Seele]

In some of the Focal Press books, the chapter on using 35mm film often contains a table detailling the length of film required for any given number of exposures, and the one for 36 exposures is always 1.64m. I also measured some old films with full Leica-style trim and they came to this measurement within very close limits. More recently, pre-packaged films tend to have a short leader rather than a full Leica-length leader and that would make the overall length a little shorter, perhaps, but I have not done any actual measurement lately, so cannot say off the cuff.

 

[rbsinto]

So then, Phil came up with the plastic thingy you had to put in the 45's to get them to play on the stereo...you're telling me Phil came up with those too...???

Oy!
Didn't they teach you anything in school?
Phil came up with the 78, but it was his friend, Lenny who thought of the plastic thingy.
And yes, before you ask another silly question, he was the same Lenny who was Jerry Olch's mother's butcher.

 

[sevo]

Here's a suggestion, though. With most lathes of that era, there were separate gear sets for metric and imperial. As a microscope manufacturer, Leitz would have had most of their machine tools set up for imperial, because that was the standard

And that independent of microscopes. The metric system was introduced in Germany in 1870, and at the turn of the century, the metric system had just about begun to replace old (imperial and local) measures in Germany. The last trades stuck to non-metric up into the late twentieth century, and the industries mostly got converted in two big wartime waves, when most orders were from the war ministry and harmonized to metric standards...

 

[Roger Hicks]

And that independent of microscopes. The metric system was introduced in Germany in 1870, and at the turn of the century, the metric system had just about begun to replace old (imperial and local) measures in Germany. The last trades stuck to non-metric up into the late twentieth century, and the industries mostly got converted in two big wartime waves, when most orders were from the war ministry and harmonized to metric standards...

Gosh! Thanks very much for that information!

I've always been fascinated by the fact that Leica screw mount is not 39x1mm (as I mistakenly believed as recently as the 1980s) but 26 tpi.

Cheers,

R.

 

[David Hughes]

Dear David,

I've never measured the cassette and didn't know it was an inch, which is, as you say, an interesting fact.

Here's a suggestion, though. With most lathes of that era, there were separate gear sets for metric and imperial. As a microscope manufacturer, Leitz would have had most of their machine tools set up for imperial, because that was the standard -- just as we use 1-3/8 inch film (half of 2-3/4 inch Kodak film, slit and perforated) and cut-film registration is standardized in inches. For that matter, the standard tripod socket threads are 1/4 inch and 3/8 inch.

If you load 5 feet dead, you're in effect knocking off two of the blank exposures at the beginning of the film, so the 'carelessness' theory has something to recommend it. On the other hand, so does sloppy translation: the original Focal Encyclopedia (1956) gives 'about 65 ins or 1.6 metres'; they also refer to 'unspooled bulk lengths of 25, 50 or 100 feet, or of 5, 10, 25 or 30 metres' (page 1070) and we may fairly assume that metric bulk loads were more normal on the continent. Somewhere I have a sealed, German-market 1936 tin of Agfa 35mm film and when I find it again I'll check the nominal length.

Cheers,

R.

Hi,

Were your ears burning last night and early this morning? Anyway, I've measured a lot of very elderly cassettes by Agfa, Leitz and Anon and a nominal 1" seems to be the answer but few are circular now. The best one where I managed to measure from unworn black paint on both sides were dead on one inch. To my surprise a lot tapered slightly... An inch doesn't seem odd to me given the RMs involvement in things. Leitz may have had stocks of it as tubing; making me wonder about the draw tube on the Elmars now!

As for 5ft, I got the figure from Morgan & Lester and Kisselbach's books. Looking at old adverts 36 exposures crops up most often, eg

"3x Perutz Leica Special Film Rolls H&D 45 for 3 x 36 = 108 exposures in an air tight tin 8/-

3x Ditto but on daylight loading spools in tin 10/-"

And they said it gave "20" x 16" practically free from grain" in an advert dated October 1929 which was the first advert I saw for a Leica camera in "Amateur Photographer" after going through a heap from 1929 and 1930.

But there were also 20 exposure Kodachrome and Ilford Colour Film Type D mentions by the 50's. And right up to the 80's 50ft and 100ft were mentioned as the bulk package. With 5m and 17m mentioned once. Looking at old tins the refills just say "36 EXP".

And Brian Coe mentions 18 exposure cassettes of Kodachome, process paid at 12/6 in 1936.

As a side issue, the adverts for film in AP up to 1930 were mostly for plates and just now and then for roll film. The Perutz ?cassettes? I mentioned were offered as an option with the Leica package. (Model A, f/3·5 lens, RF ?FODIS? ERC and three spools for £20-5/- and secondhand 15 or 16 gns in 1929.)

BTW, I can't be the only one who has bought a Leitz lens and found it had been overhauled and serviced and re-cut to 39 x 1 mm (as people might have expected) and it cost a lot to get it re-cut correctly to a sort of hybrid. FED's seem cut to a sort of hybrid too. I must get some screw gauges and do more research...

Regards, David

PS I think I have an Agfa bulk tin somewhere from the late 30's. I'll look for it if I ever get a spare moment.