I know. You just run the -corner- of a sharp Ever-Ready single-sided reinforced blade to cut the width of the tape (held firm in a dished groove) in the editing block at its 90 or 45 degs slit. Agfa used to make industry-standard 1/4" jointing tape. You may need a Chinagraph wax pencil when editing. But not sure if the latter are still around.
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