I have a Coolscan II connected to an Advansys ABP940U SCSI card. I haven't owned this scanner from new and I've never seen it working correctly. So I've no idea what's the source of the following weird problem.
When I scan, using the coolscan backend, some lines of the scan are offset by 1 pixel from the previous line; about 60% of lines, seemingly at random, are affected, so after 24 lines I'm typically 14 or 15 pixels across. After 62208 bytes (24 lines of grayscale or 8 of color), the next line is back at the original position (62208 bytes is the amount of information returned by the scanner from a single SCSI read). This produces a jagged effect; http://guests.deus.net/~rp/sample.png shows the top corner of a scan, showing the effect I've described at the edge between a slide mount and a very light slide on a grayscale scan. In color, I also notice that each line is only one color. http://guests.deus.net/~rp/sample2.png - a picture is worth a thousand words. That's from part of the middle of an image. So my questions are: - is this scanner functioning properly but being driven wrongly, malfunctioning but usable, or a paperweight? - if the scanner is OK, what is my best route to getting proper scans from it? I'm happy to do some C programming, so I'd need to know what's the best way to get specs and whether I should be working on the coolscan or coolscan2 backends. If there's any more information I can provide or tests I can carry out to diagnose this problem, please let me know and I'll do so. sane-backends 1.0.13, Red Hat Linux 7.3, kernel 2.4.18-3 . Thanks, Richard Poole
