Is there a trick to determine what type of film you loaded (LF)

steveb533 · Mar 23, 2013

Hi,
I loaded some large format film a while ago and I cant remember if it is c-41 or b&w...I think it was c-41. Is there any trick to figuring that out, that anyone knows of? Also if I cant determine which, it would make more sense to develop with b&w chemicals I guess? Thanks

Steve

Rudeofus · Mar 23, 2013

Do you think you could clip off a tiny corner of the film sheet somewhere in the dark, then reinsert the remaining sheet back into the film holder? The difference between b&w and C41 film stock should be plenty obvious (orange mask!) even before any development has taken place ...

Shawn Dougherty · Mar 23, 2013

There are notch codes in the upper right hand corner if the film is held vertically with the emulsion towards you. The notches are different for each film. It will be easier to figure out by feel if you can narrow it down to only a couple of possibilities... or you could sacrifice one sheet and look at it in the light.

Pinholemaster · Mar 23, 2013

Check the notch code on the film. Basically feel for it to determine the various notch shapes and sequence, the look up the sequence of notches. Then you'll know exactly what film you have.

If you have the boxes you film came in you'll see the notch code printed on the label.

http://en.wikipedia.org/wiki/Notch_code

Worker 11811 · Mar 23, 2013

If you have some sheets of film already developed, check the notch codes on those.

Practice feeling the notches with your eyes shut. Different notches feel pretty distinct, once you get the hang of it.

Compare the known to your unknown. (In the dark, of course! )

Bill Burk · Mar 23, 2013

And of course, you probably have used the same film before (and have developed sheets to compare notches).

Or at least you have part of a box of fresh film to compare...

bdial · Mar 23, 2013

The codes for B&W and color (at least for Kodak films) are pretty different. The code is also illustrated on the box (again, Kodak products, Ilford too, I believe) so you can look at what to expect before turning out the lights.
As sort of a last resort short of turning on the lights on a sheet, put the sheet over a card or piece of paper and trace the notches with a thin lead pencil, then put the sheet back in the holder.

removed account4 · Mar 23, 2013

in addition to the good suggestions already mentioned ...

nicolai morrisson has a pretty good list of notch codes
http://web.archive.org/web/20110715082248/http://photondetector.com/tools_ref/filmdata/
( sadly i had to consult mr peabody for help ! )

and this is in the articles section here on apug
(there was a url link here which no longer exists)

good luck !
john

eddie · Mar 23, 2013

I once used Silly Putty to determine what the film was. I just pressed the notches into the Putty, and went to look it up.

steveb533 · Mar 24, 2013

Thanks alot for the responses! I didnt know about the different edge markings. I will try that. Thanks again

Steve

Is there a trick to determine what type of film you loaded (LF)

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