Can you use a scanner under an enlarger??

[johnyslo]

When I first saw the BetterLight scanning backs for large format, it dawned on me that in theory they are simply a flatbed scanner placed at the focal plane of the lens. I'm sure that it's a bit more comlpicated than that in practice, but the basic principal seems accurate. So that got me thinking, could you place 35mm, 120 or 4x5 film in an enlarger and focus it onto a flatbed scanner at 8x10. I know that I would have to experiment with the light intensity and color balance, but it seems like it should work. It also seems that it would improve the effective resolution since you would be projecting the 35mm or 120 slide or negative over more pixels. Has any one ever tried this? Did it work?

Also, has any one ever tried scanning a slide or negative on a regular flatbed scanner (one not meant for transparancies) using an external light source, like the sun or an enlarger lamp?

Any info would be greatly appreciated. Thanks!!

[8x10 user]

It would work if you had an open sensor moving around the plane of focus on the enlarger (like the sensor in a BL back). The problem is that the flatbeds would be designed with a built in lens that would be in the way. The only way I think of to make it work without redesigning the flatbed would be to use a ground glass instead of a regular base glass or if you could trying making a paraffin "screen" on the scanners base glass.

You see... the light is going to be constantly moving away from the lens center "axis" of the first lens. You need something there to redirect the light rays back into the second lens in order for it to produce an image. This is the same reason why we need to use a ground glass in a view camera. The lens in our eyes and the lens in the camera would not work together without it.

[8x10 user]

There is a small chance that someone might have once made a lower resolution scanner that functions without a lens by having the sensor so close to the material that it is able to "contact" scan.

[Bruce Watson]

Can you do it? Sure. Do the experiments and find out if it's worth doing or not. Let us know what you find out.

[Nathan Potter]

Yes, you can try it. The lens in the scanner will focus on the aerial image from the enlarger. As pointed out by 8X10 above, at the corners of the enlarger image the rays are off axis by a lot so these may not be rectified by the lens in the scanner - I think probably not without significant color distortion. A longer focal length enlarger lens would be useful in mitigating the oblique angle of off axis rays from the enlarger. Don't know what else you might run into but as Bruce says - there's nothing like an experiment followed by optimization. Use a ground glass to focus the enlarger at the sweet spot of the scanner focus - then remove the GG for the scan.

Nathan Potter, Austin TX.

[Cesar Barreto]

Canon Lide scanners (at least some models I tested) don't use optical elements, but just a sensor bar that crosses the whole bed's width. I tried this on the back of a 5x7' camera but the result was so awful, since a lot of noise and bugs surely are corrected by their software without notice while making regular scanning.
Someone wrote a college paper-work on this and it can be easily found in the internet.