The CIS to SCN conversion utility provides for setting a variable to the first note position from the left. The last note position on a 9/inch roll will normally be 3300 positions to the right of the first note position. Thus I have my SCN.EXE utility set to 145 and 3445.
I have no idea how it's done, but once the scan begins accurately, the software tracks a wandering roll remarkably well. This is particularly noticeable on a very long original roll. A good example is Ampico roll # 100775, Liszt 1st Piano Concerto, 1st, 2nd, and 3rd Movements, played by Marguerite Volavy. My copy of that roll is original, it is huge, and its in good condition. Throughout the length of the scan, the paper wandered onto the take-up spool at times up to 5/8" from true tracking (My take-up flange ends are not big enough to contain the whole of a large roll.). Yet the final midi file plays as if the roll tracked perfectly throughout the scan.
The front end of SCN.EXE provides for a graphic representation of this alignment. It will not be seen if enter is hit throughout the front end setup. Hit enter slowly throughout the front end variables setup and wait for the lpi calculation. At that point, hit enter once to bring up the initial graphic representation of the roll. From this point, hit the space bar repeatedly, slowly and the graphic image will advance through the front end of the roll a page at a time.
The bottom half of the screen will display the full scale of the roll normally. The top half of the screen will display the bass half of the roll inverted. Gets a little tricky relating one to the other because of the visual misalignment.
At this point, it is prudent to have rewound the roll back to the beginning so that the front end of the roll itself can be compared to the computer screen. The following pics illustrate this side by side display.
Note the sustain perfs on bottom half of the screen image, which displays full scale.
Note the same sustain perfs on the top half of the screen image, inverted, falling on the red line.
Upper display is bass half of the scale.
The sustain perforation should line up with the vertical red line. If it does not, hit esc, enter to terminate the SCN conversion and try again with different first and last note variables. Takes a bit of experimentation.
Not all rolls will cause the sustain perfs to fall on the red line. Some rolls have thicker or thinner right spool ends than the majority. I find it prudent to check this portion of every scan, before proceeding to the midi conversion. An unpredictable but small percentage of my rolls will require settings of first-note=118, last-note=3418, something determined by trial and error.
It is becoming increasingly clear that substantial time can be saved if the CIS and the roll are always in the same specific relationship to each other. Makes finding the position for "note 0" very easy. In an earlier portion of this web site, I illustrated a positioning pin that mistakenly had the CIS mounted always in the same position every time it is loaded. However, not all right spool ends were manufactured to same dimensions. As a consequence, if the CIS is located in a rigid location, the roll could easily be off by as much as 1/16" either side of center. As a consequence, I have removed that positioning pin and now load the CIS into alignment with the left edge of the roll at same place every time. A couple of handwritten marks on a sticker on the CIS make this very easy. Thereafter, SCN.EXE can be used in batch mode to process a whole day's CIS files, with 'note 0' always in same place for all. On my scanner, 'note 0' is at 140.
Stay tuned...... More to come.......
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