For all practical purposes ASA/BSA/JSA/EI are the same. The DIN system is calculated Log 10. In the past DIN speeds were written with the speed number followed by /10. (example: 2/10)
The Scheiner system is obsolete. It was distiguished by 0 following the number.
has both human-readable edge numbers and machine-readable information printed as a latent image on its edge at the time of manufacture. In addition to an incrementing number, a zero-frame reference mark, consisting of a filled circle approximately 0.025 to 0.030 inches (0.64 to 0.76 mm), is printed adjacent to the digit of the human-readable edge number that is closest to the tail of the film. The frame immediately above the zero-frame reference mark is the one referenced by that edge number. The numbers are printed so that the center line of the zero-frame reference is aligned with the center-line of a perforation. The spacing from one key number to the next is 64 perforations. A mid-foot human readable and a mid-foot machine-readable edge number is printed halfway between each key number. The midfoot human-readable edge number consists of a zero-frame reference mark and the adjacent edge number that is nearer the head end of the roll plus an offset in perforations that is always 32 perforations. All characters of the mid-foot edge number are approximately xh size. A similar system currently under study by a SMPTE standards committee has been proposed for 16mm.
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