Illuminating (Digitizing) Negatives

[Mike B]

I want to find if anyone has experience or ideas about illuminating film negatives for digitizing. I’m using a 10+ mpixel Canon Rebel XTi camera. Initial trials use a high-CR lamp.
Using 8-bit Gimp gives coarse results, so I shot raw images +2, 0, and -2 stops and used Photomatix to create high bit depth images. Using 16 bit Cinepaint the results are better, but I’m still losing color information.
I suspect that the “white” light illuminating the cyan, magenta, and yellow dyes of the negative is not being accurately represented by the RGB sensors of the camera. I fear some wavelengths of the lamp may be overlapping the sensitive areas of the camera’s RGB filters.
BTW, I need to scan negatives larger than 35mm, so even used a scanner is expensive.
I’m realizing how complicated color spaces and color management systems are. Any help, or if need be technical information as to why this cannot work, will be greatly appreciated.

[IMSabbel]

Edit: disregard that, i overlooked that line that said you are scannig big negatives.

Still i would recommend a scanner. There are A4 Flat-scanners for a few 100$ that support a back-illumination unit. And they all have vastly better defined lightsources and better colour-resolution than a digicam.

Also, you are _not_ doing those medium format negatives any justice by using a 10MP camera....

______


If its 35mm negatives, and you have to do that more than a few times, do yourself a favour and get a slide/negative scanner.

Those arent too expensive (got one for about 400$ 3 years ago), and they are vastly superior to anything you can get done with a digicam (especially for negatives).

Any decent one will have native 16bit colour resolution.
Mine also had the option to combine 16-bit with multipass scanning (i.e. the same you are doing) in batch mode for a whole film-strip at once. Plus the firmware supports negaives natively and has optimised settings for them.

Also, the resolution will as good as the substrate (with higher ISO films, the individual grains are visible)

[dulridge]

Most print shops are scrapping their drum scanners in favour of CCD devices - you may be able to pick up a used one for next to nothing. But they are big, loud and finicky.

I got one about the size of two TV sets (large) for nothing. Shipping would have killed the deal though, these things are heavy and delicate.

[Mike B]

I have a "name brand" consumer flat bed scanner, but the actual optics are pretty lame compared to the reported pixel rating.
Actually, the Canon digital camera gives results that beat my 35mm camera, and rival or exceed the 645 camera.
The best I've run across is a Nikon Coolscan on Ebay, but they end up going for $700+. Budget, priorities, and responsibilities say this will not happen anytime soon.
I tend to learn an awful lot pursueing some of these "odd" projects, so it actually goes (a little) beyond getting these scanned. Although, if I had the coolscan, I'd be learning something else!

[paulr]

You can do pretty well with an Epson Perfection scanner that is in the $400 range. A typical document scanner won't do nearly as well.