Hi,
Been thinking about this.
We are used to buying 35mm negative film in short lengths in metal cans or cassettes. Somewhere there's a factory making B&W 35mm negative film by the mile and then cutting it up into (say) 400ft lengths for the cine camera users. They get to the end of the run and the roll can only be (say) 290ft long. So they scribble on the label 290 ft and put it to one side. Every now and again a dealer in (say) China buys all these cans of odd lengths and takes them back to China and puts them into cassettes...
Or, the factory notice a scratch on the film and scrap the batch or rather sell it off cheaply like supermarkets do. You know, 20 % off, then 50%off then 90% off then free to staff. My betting is they still make a profit as they allow for this to happen.
More to the point, we only know the retail price of minute lengths of 35mm film after several middle men have handled it. The factory may sell it dirt cheaply and still cover their costs on this (say) 1% of their run.
I've know this happen with other items made by the mile and sold in similar ways. A bloke I know runs a small firm and makes things using only these off cuts and he told me he paid 50p a metre and retail it costs about 12 quid a metre... But the factory ring him and tell him they've a lot for sale and he either takes the lot or goes without.
Just my 2d worth.
Regards, David
