I suppose my equivalent is a technologist who spends more time in here talking about film than actually shooting the stuff. Never mind, I'm off to Goa in a few days, shooting 5x4, what fun.(posted 9320 days ago)>> "On a serious note I was wondering if using the method of printing the sprocket holes until they just disappear and then picking the exposure that looks the best was a good way to find your camera's correct ASA setting for a given film etc."
No, because it makes all sorts of horrible assumptions about the density range on the negative and contrast of the paper, and your way of metering, and so on. It *is* a reasonable method for finding the minimum printing time of a negative (or, indeed, entire roll of film).
A better way of getting a very rough EI, with my definition of EI, is: put a card (it doesn't have to be an 18% card, but it shouldn't be coloured) in a position with constant illumination. Meter it. Photograph it at 5 stops more, then 4, 3, 2, and 1. Look at the negatives. Pick the one that shows the grey card just off film-bass- plus-fog (i.e. density about 0.1). If this is the "+4 stops" negative, you guessed the correct EI. If it is the "+3 stops" negative, you should halve your guess. And so on for the other negatives.
You can adapt this method to find your own EI, if your definition is different to mine.