Width and tolerance of 120 film?

[grainyvision]

I'm trying to simply find the width and tolerance of 120 film without having to pay $60 for ISO 732:2000. Does anyone happen to know these numbers? Wikipedia says the nominal width is 60mm (with no source other than ISO 732), but every film I've found measures around 61mm +/- 0.2mm. I'm cutting my own film and currently have it cutting at 60.5mm and trying to figure out if I might have problems due to tolerance. The only real problem I've noticed so far is that it has more tendency to fall off plastic reels than other (developed) films I've tried, but then I don't normally use plastic reels since converting to steel, so not sure how common of a problem this might be. Also wanting to make sure the film won't have any problems in strange cameras or something by potentially being out of tolerance

 

[John Salim]

You can obviously measure very accurately, so why not simply measure the width of ( undeveloped ) Kodak and Ilford film ?
You can't go wrong with those examples.
.... and I'm sure you know the width of the paper backing is very slightly wider.

John S

 

[AgX]

Wikipedia says the nominal width is 60mm (with no source other than ISO 732)

There are several Wikipedias... mine says 61.5mmm ...

 

[AgX]

What does ISO say...?

ISO says 61.5mm

(but I have not got the ISO figure for tolerance at hand)

 

[ic-racer]

Don't know if this helps.

 

[AgX]

So much about the trustworthiness of an ISO document, stating in the text a figure that only is the lower limit.

 

[grainyvision]

@ic-racer where did you find that? I ended up caving and buying the stupid specification to figure it out because I found so many conflicting sources.

According to ISO 732:2000, the width of the film must be between 60.7 and 61.7mm. Most films I've measured have been around 61.2mm. Also, for future reference, the length of the 120 film must be 820mm to 850mm, though others have said the film can be as small as ~790mm.. that might only be for older film that breaks spec though. And finally, to save anyone else from buying this, the thickness of the film and backing paper must be 0.24mm +/- 0.4mm, and the backing paper width must not exceed 62.90mm, though there is no specification for the minimum size other than "it should cover the film".

And for future internet people, the length of 220 film is between 1651mm and 1700mm. The width is the same as 120

If anyone has any other info they want from the spec, just ask and I'll publish it here.

Other fun facts I didn't even know were in any specification:

B/W film has no standard edge markings on the "exposed" backing paper. Color negative (C-41) has squares around the edge. Color reversal (E-6) has + signs/crosses.

The sealing sticker to close the exposed roll should have some kind of color on it for color negative or color reversal, and should have no color on B/W film

edit: I also updated wikipedia to include this for US/english version anyway

 

[tedr1]

the thickness of the film and backing paper must be 0.24mm +/- 0.4mm

the tolerance is greater than the dimension this seems illogical, perhaps it might be +/- 0.04mm?

 

[grainyvision]

the tolerance is greater than the dimension this seems illogical, perhaps it might be +/- 0.04mm?

Er you're right. It's +/- 0.04mm.

 

[AgX]

This is the first time I am puzzled by contrary figures in ISO documents, seemingly due to revisions.

In 2000 when the decrease of rollfilm was foreseeable, such revisions were made...

 

[grainyvision]

This is the first time I am puzzled by contrary figures in ISO documents, seemingly due to revisions.

In 2000 when the decrease of rollfilm was foreseeable, such revisions were made...

Really curious what the older revisions of ISO 732 gave for these dimensions, but I refuse to buy anymore copies of ISO documents

 

[ic-racer]

Here is a better image of the document; specifically the 120 section. This document is ASA, which is pre-ISO. I did not know of ISO732 but most of my 120 equipment was probably designed during the time this older ASA document was valid.

 

[grainyvision]

Interesting. I wonder why the acceptable width of 120 film has decreased so much. >1mm of difference across the tolerance range of the older standard and the latest ISO 732