DIY film scanning with flash + macro lens.

[Garbz]

We are attempting to digitise our film collection at home, however our scanner a cheaper Canon flatbed scanner takes about 2min per frame. Now working on the principle that the if you backlight a film frame and then take a 1:1 (or 1:1.5 in case of an APS camera) macro photo of the frame produces an instant print I set about building a rig to scan film quickly.

Ok so it's very basic and currently still in it's first stages to check if the idea would even work. There are obvious problems like can the 12bit RAW file of the camera (which is converted to a gamma of 2.2, 16bit file) compete with an image inverted by the scanner driver (true 16bit gamma 1.0 processed file saved with a gamma of 2.2). So easy enough I set about to do a quick test.

First the rig:


This is currently incomplete but the idea is that the frame is held on the sides and flattened by pieces of plastic covered in felt. This doesn't appear to scratch the negative when it is loaded or unloaded. At the bottom is the flash unit, and half way up is a sheet of paper to act as a diffuser. The top plate has a hole in it and while it currently isn't used the distance from the back edge to where the film is held is the same distance as from the tripod socket of the D200 to the centre of the sensor. This is for future things to hold the camera so I don't even need a tripod.

And the results:

On the left (or maybe top) a scan from the Canon flatbed with film holder and backlight (2min scan time not including the loading of the film). On the right (bottom), the photo from my rig, processed by batch in photoshop. (30 seconds including loading film and focusing camera which would not normally be done for subsequent frames).



Overall I am very happy so far but a bit of fine tuning is needed. The film colour conversion came out well with the photoshop plugin ColourNeg actually doing a better job of colour inversion than the scanner despite the scanner having the extra bits to play with. I also haven't figured out what colour temperature or how to create a gamma 1 curve in CameraRAW so I can get a decent negative to work with from the RAW file.

The other obvious problem is the brightness inconsistency. This can be fixed by getting a better diffuser, moving the diffuser further away, or easier still shooting at a lower aperture. However the lower aperture idea will have to wait for a more stable focusing / holding system since the tripod standing on carpet lead to quite a few blurry (but consistently lit) shots the first time I tried this at f/4.

Stay tuned

[Mike_E]

So the enlarger thing didn't work, eh?

[Garbz]

Sorry Mike I haven't had access to the enlarger yet. My friend who has it is working stupid hours at the moment. Although when I think about scanning the entire surface of the scanner at 4800ppi you end up with 16GB TIFF file I think, so that's the exact opposite of what I am trying to achieve here.

[Pure]

Quote: Originally Posted by Garbz

16GB TIFF file

ouch.