24 bit would be 16,7 millions shades, so I doubt it somehow. maybe its 10 or 12 bit? 16 bit would be 65K shades - something you get when you save your files in 48 bit color tiff (possible in PS and PSPS) after scanning.. which would be extrapolaion anyway, since I don't think the scanner is 48 bit. Maybe 36 bit (would give you 12 bit greyscale which is plenty I think).