cramej
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- Dec 29, 2009
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I wouldn't call the 15 vs. 16 frames a "dilemma" -- 16 645 frames is the exact same length as 12 6x6 frames (I process enough of both to be sure of this). Why Mamiya and a couple others chose to only give 15 frames I couldn't say.
In any case, you're correct in understanding that some processing machines require exposing a short bit of the film tail -- but it's the tail that gets fogged, not the head, because it's that end that gets unrolled when the film is processed; the taped, head end is the last to come out. If the processing machine is fogging into the first frame, it's happening at the end of the roll, as the machine sees it, possibly indicating that the feed cassette is being opened too soon (i.e. someone is in a hurry, trying to maximize their roll count).
When I worked in a lab, we would always unroll 120 completely so we could remove the tape. This was so it didn't come off in the processor. The head end was what usually got taped to the leader.