Agreed SRS -

I think the original question has been answered, although the original requestor may not have figured it out.

Slides are meant to be viewed by transmitted light. Document/Photo scanners look at reflected light. To convert slides to digital, you do need (for best results) to use a slide scanner, or a slide adapter on your document scanner, that passes light through the slide. You can also get adapters for your digital camera, but the light still should come through the slide if you want good results.

For common films, there is enough correlation between the transmitted color and the reflected color to allow reasonable conversion with document scanners, but the small size of the slides means you need to scan at very high resolution, and expect to do a lot of color correction. Don't expect best results.

GUEST above asked about the equivalence of digital pixels to film.

For the common snapshot film cameras, with auto focus and auto exposure, especially as used by most casual snappers, careful use of a 2 or 3 MP digital camera will equal the results obtained with film. Most cheaper cameras use lots of field depth - which means fuzzy focus over a long range, and pretty sloppy central focus, so even though the film "records" a lot of pixels, it's mostly blurs.

Most of the writers/editors of the semi-tech publications that frequently test and review photo equipment currently "opine" that something like 4 or 5 MP cameras are "equal to film," although that assumes comparison to reasonably proficient "pro-am" photographers using good quality cameras (35 mm) with commonly used film and print processes.

Ansel Adams used 8 x 10 inch plates, and achieved 600 (maybe up to 1200) dpi resolution on the plates. At 1200 dpi on 8" x 10" you need about 115 MP - if you think you need to match him. Multipy by 6 or 8 if you want to do it in full color, depending on how you intend to print.

To decide what "MP" number is equivalent to film, you have to agree on "who's film." Most people will not see a difference between what they snap with their new 4 or 5 MP digital and what they might snap with their trusty old 35 mm SLR, assuming similar care in taking both shots.

John