Can a 35mm film scanner be used to digitize microfilm?

February 6, 2007 12:58 PM

Is it possible to use a 35mm film scanner -- such as a Minolta DiMAGE or Nikon Coolscan -- to digitize 35mm microfilm? Film scanners like these are much cheaper than microfilm scanners and take up much less space. Has anyone tried this and been successful?
posted by cog_nate to technology (8 comments total)

I have not tried it but I have worked quite a bit with film scanners so I have a few thoughts for you to consider or research:

* What resolution would be required to get usable results from microfilm (I don't know the magnification rate). Will a film scanner be able to pick up enough detail?

* Negative film has a heavy colored back-mask. Film scanners compensate for this. You can probably re-compensate if you need to. I think most film scanners probably support slides, though, which have no color filter on them, so that's probably not really a problem. Just a thought.

* 35mm film scanners, all the ones I've used, are a pain to use in bulk. Part of this is because you spend a lot of time pre-tweaking the scan settings - it's easier to get a good scan the first time than to correct a bad scan (bad white points, color balance, etc etc). This may not be an issue with microfilm since you're not trying to get a beautiful image. Still, though, all the film scanners I've used have required user action between each frame. Once I figured out how long it took me to scan and prepare an image I found out that it was cheaper to send the film out to be scanned, on a per hour basis. A LOT cheaper.

* Speaking of which, is microfilm in "frames" or is it continuous? Are you going to have to take multiple images and align and stitch them together?
posted by RustyBrooks at 2:12 PM on February 6, 2007

Oh god, you would never want to. Let's put it this way -- it takes a decently good person a half hour, going frame by frame operating one of these scanners to get a 35mm roll in... and that's less than a second of video.

From my understanding, the microfilm scanners are similar to the scanners they use in photo labs these days to read an entire roll of film into a printing machine. It scans at about 5-10 frames per second.
posted by SpecialK at 3:58 PM on February 6, 2007

Just to third everyone here: stay far, far away from 35mm scanners. They're a complete pain in the ass to use, and I doubt they'll give you anything like the resolution you need for microfilm. If they did, it'd take 10 minutes per frame, easy.
posted by bonaldi at 7:11 PM on February 6, 2007

They have the resolution. It'd be a huge pain. Don't do it.
posted by rbs at 8:54 PM on February 6, 2007

You'd be better off using a flatbed scanner that can scan transparencies than the film scanners. The Dimage does not accept anything more than film strips and isn't well suited for batch scanning.

The Coolscan apparently has a rollfilm adapter but not for the bulk of a microfilm.

If you only had a few frames of microfilm and were willing to cut it apart then you could use a film scanner without any problems.
posted by JJ86 at 6:09 AM on February 7, 2007

A sidenote to bonaldi, yes film scanners have more than the requisite resolution and a decent modern scanner could easily scan a frame very quickly.
posted by JJ86 at 6:12 AM on February 7, 2007

I use a 35mm film scanner for 35mm film. I've never worked much with microfilm, aside from using it in the library on occasion.

In response to RustyBrooks, most film scanners do the color-correction of negative film in software. The scanner "sees" the film with the orange base color, and this is subtracted in the scanning software on the host PC. I don't know of any (consumer) 35mm scanners that remove the film base in hardware. When I used to work in a professional photo lab, we had equipment that used graded filters to correct for the film base (Fuji FA series optical printers, in case anyone cares) and they were a massive pain. You have to have a different filter for each film formulation, which can be each brand and type, and speed. So Kodak Royal Gold 100 has a filter, RG200 has a different filter, Fuji Superia 100 has another filter, etc. I don't think anyone uses that kind of technology anymore; even the modern digital processors just scan the film with the base-color intact and fix it in software.

On my scanner, which is not a particularly nice one (PacificImage PrimeFilm 3650 Pro3), it takes about two minutes to scan a 35mm frame at 3600 dpi, using the scanner's FireWire interface. This doesn't include time to move the film, autofocus, preview, etc. So it's not a fast process. The only nice thing about this unit is that it has an automatic batch feeder for 35mm strips and rolls.

The big problem with microfilm, and what would really make me decide whether it was practical or not, would be feeding the film. If you have to manually advance the film, it's going to take months to do a few rolls. So the key is going to be getting a scanner with an autofeeder (like mine). But what I can't remember is, does your microfilm have sprocket holes?

My recollection is that it doesn't have holes, and if so, you're screwed -- give up on the consumer-scanner idea now. All the auto-feeder systems for 35mm print film rely on the sprocket holes, and won't work for un-sprocketed film. If that's the case, you'll need to get a microfilm scanner. Even a non-autofeeding consumer film scanner will probably give you problems, because the film holders are all designed for sprocketed film...you'd need to get a special film holder, at least.

If it does have sprocket holes, then you might as well give it a try. Get a high-resolution consumer scanner, and then get some good scanning software. (As a rule, they all come with software that's worthless -- I'd recommend Silverfast if you can afford it, and VueScan if you can't.) You'll know immediately whether it's a usable workflow or not, and if not, you can return the scanner and get a purpose-built one.
posted by Kadin2048 at 8:16 AM on February 7, 2007

Thanks, everyone. I'm still waiting to receive the microfilm on interlibrary loan, but I've looked in our collection and the microfilm we do have is sans sprocket holes. Time to start saving pennies for a new microfilm scanner, I guess.
posted by cog_nate at 10:15 AM on February 8, 2007