I asked the list a week or two ago whether it was possible to scan an
aerial image from a slide projector using a flatbed scanner. Since then
I tried a bit of experimentation and y'all can make up your own mind.
See the images on my website at:
<http://home.attbi.com/~chucknorcutt/wsb/html/view.cgi-photos.html-.html>
Sorry, but you'll have to first skip over the images of my lenses for
sale, he he he. :-)
The first thing I did was open up my scanner and disable the light. I
had been concerned about ruining the scanner somehow but on my Visioneer
4400 it was a piece of cake. Remove two screws from the bottom, swing
the cover up and off from one end and unplug the connector feeding the
lamp. I lifted off the top cover and rested the scanner on its side
about 4 feet from the slide projector. The projector is a Kodak
Carousel 750H with a Schneider Vario-Prolux 70-120mm f/2,8 zoom lens.
(Thanks to John Lind for recommending this lens which I found NIB on the
bay)
I focused the slide projector on a piece of paper resting on the
scanner's glass bed. I then removed the paper and scanned what I
presume is an aerial image. I did get a very dark image with the center
section totally blown out across the full width of the image. The
scanner was clearly focused on an image but it appears that the slide
projector's condenser creates a hot spot in the center which totally
overwhelms the scanner's image sensors. Trying low and high brigtness
or higher magnification to spread the image out didn't change a thing.
The projector's bulb overwhelms the flatbed scanner. I don't have any
ND filters. I tried a polarizer with no effect. You will get this same
effect if you try to scan a lighted flashlight resting on the glass.
I next tried projecting through a white piece of paper. This time I got
a fair image without a hot spot. However, it's totally lacking in
sharpness, color and contrast relative to the original slide. This
didn't surprise me very much as I can't see very clearly at all through
a piece of paper.
I next tried (with a different slide) using a thick, white plastic bag.
Not much of a test since the bag was pretty wrinkled. Also, the hot
spot showed up again but this time reduced to a small hot spot in the
center.
I also tried scanning through waxed paper and a make-shift "ground
glass" made from the clear portion of a CD case that had been scuffed up
with #400 grit sandpaper. Both made lousy ground glass plates and
exhibited the hot spots seen previously.
Probably the only way to get a good image will be to kill the hotspot on
the direct scan of the aerial image. Right now I'm out of ideas but I
had a lot of fun. Maybe I need to project the slide with a cold light
enlarger but I don't have one.
ps: I do have a ScanWit 2720s film scanner but I'm looking for a cheap
way to beat the 2700 dpi limit.
Cheers,
Chuck Norcutt
Woburn, Massachusetts, USA
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