Scanning MF with a flatbed?

[Don Simon]

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.

 

[markc]

The bluriness could be coming from the neg being too far from the glass. There is a very narrow range of focus for most scanners. They usually need to be so close that it doesn't take much of a curve to get Newton rings. Is the cardboard spacing the neg any higher above the glass than what the holder already does? If you are having trouble with the holder, you could try mineral oil between the glass and neg, but that gets messy. They may be coming from the glass top. Try using some cardboard to space the top away from the neg carrier.

 

[Don Simon]

Thanks, I think it is curvature after all. It's often barely noticeable but seems to be unavoidable due to the design of the plastic neg holder. I'm guessing something that stretches the film flat and firmly holds it that way is what's needed, though despite trying with the bits of card etc I don't think my neg holder can be made to do that.

Probably a silly question, but is there any reasonably reliable way to 'de-curl' film? Having been stuffed inside a roll for ages before being taken out and developed on yet another roll I know it wouldn't be easy to flatten it, but are there any methods that might work? Thanks again.

 

[mysteryscribe]

There used to be a negative flattener solution but I havent seen any in years. It might still be around. Have no idea how well it worked.
Have you given any thought to masking tape

 

[Don Simon]

Masking tape could work, but then I'd have to keep cleaning the scanner glass. Actually I think the negs are not supposed to touch the glass since there is a separate lamp in the top of the scanner for film scanning, and when I placed the film under the neg holder instead of inside it the scans didn't come out too well. I think this one's going to take some experimentation and a lot of patience. Does anyone know where I can get that?

 

[mysteryscribe]

I was thinging tape to the carrier or cut a piece of card about the same thickness and tape to it. I scan a lot of cut film and some cut up rolls but I made my own back light and the weight of the light holds the curled film flat.