I've been using my CanoScan 8400F to scan 35mm negatives (both colour and b&w) for a while now with pretty nice results. However I've recently been trying to scan 120 colour negatives, and am not at all happy with the scans. I use the 120 film holder that came with the scanner and insert thin bits of card or plastic around the edges to stop the film from curling, but I'm getting Newton's rings on some scans even when I can't see any curling or major curvature on the film. Another thing I find odd is that in contrast to my 35mm scans, my 120 scans seem to be completely lacking in sharpness, and not just at high magnification. I know it could be the negs themselves, but to me it seems unlikely since I mostly shot on a TLR with a solid tripod, cable release and across the aperture range. Anyway this is really quite confusing to me so I'm hoping someone might know what's going wrong. Can anyone think of a reason why I would be having such problems scanning 6x6 negs and yet not with 35mm? Thanks in advance. P.s. I'm using Canon's own scanning software. I know Vuescan is supposed to be much better, but from my brief time playing around with it I found it very hard to get the results I wanted, while Canon's software provides 'good enough' results without any effort.