With my digital camera, each photo has a unique incremental number, e.g DSC12345. When\if I buy a new one I can tell it to start from the number of my previous camera. This enables me and any customers to uniquely request\find an image from my archive. With film, I am struggling to devise a system that's not too labour intensive to enable me to keep track of my film shots in the same way. For example, if I shot 36 exposures at a given shoot, and 5 are almost exactly the same, when the cutomer see's the scanned in versions of the image I don't want to accidentally send the wrong frame to the lab for printing. I want to know that the one that has been asked for is the one I send to the lab, even if there are several that look very similar, and perhaps indistinguishable from the negatives. What method do you guys use to keep track of your films and individual frames as your archive grows?