Sheet Film Numbering System by J.B. Harlin
One of the first real stumbling blocks we ran across using sheet film was the fact that there was no easy way to identify each sheet of film. True, each film holder had an individual number, but once the film was removed and mixed in with others, exact identification was difficult. Plus, there was two of us shooting! Usually we could distinguish each frame by referring to our field notes, but some exposures were different. Different filters were used on identical subjects. On some long trips there would be over 200 negatives of one film size. We needed some method of marking each negative with its film holder number for identification and filing purposes.
I pondered the idea of using a pattern of small holes drilled in the film hold-downs located along the long side of the holder. The problem was there just isn’t enough room and drilling a small, clean, hole there was difficult without damaging the film plane septum plate below. I knew there had to be a simple way to get a unique identifying mark onto each negative.