Operator shifts in the roll images
This page lists all operator shifts in the SUPRA roll images. Shifts are sudden displacements of the roll to the left or right in the image. They are sometimes needed to keep the edges of the paper from pressing too hard against the take-up spool flanges. Shifts will cause image distortion, so this page is useful for looking at the visual effects of each shift.
The following histogram summarizes all of the shifts displayed below. Regular shifts are shown in blue, shifts occurring after the end of the last music hole are shown in green, and borderline shift sizes are shown in red.
The list is sorted by the size of the shift. Negative shifts are to the bass side of the roll and positive shifts are to the treble side of the roll (or the other way around). Shifts are identified down to a size of 3pixels (1/100th of an inch). Scroll the image horizontally to view the entire width of the roll (about 1/4 of the roll is visible in the width of the image). The shift is centered vertically in the image, with one inch above and below the shift also being displayed. When shifts occur after the last musical hole a note is given to this effect in the position fields (highlighted in green, meaning OK). These end shifts do not affect musical data extraction from the rolls.