Dear Diego, thank you for the tip about the array length; I will check this.
The FS2710 does not seem to be influenced by downloaded gamma tables. The original Canon (Windows) software feeds it 4 tables of 8192 byte length (2^12 entries of 2 byte length), but does not change them when you manually select another brightness, contrast, etc. . My guess is that Canon runs the scanner in 12-bit mode all the time, does the gamma correction in the computer, and then rounds the result to 8 bits. Our Canon backend does just that, and the results look the same as those obtained with their software. Incidentally, the Canon backend contains subroutines for the adjustment of contrast, brightness, shadow point, etc., that others might find useful. Best regards, Ulrich Deiters