Microfiche scanning

Jules> Am I right in thinking that a home flatbed scanner has Jules> absolutely no hope of providing the resolution needed to scan Jules> microfiche? Jules> We've got a *lot* of DEC documentation arrived on fiche (208 Jules> pages per fiche, estimated 25000 sheets) and scanning some of Jules> the more useful bits would be nice. So far the cost from Jules> commercial companies has either been too high or the quality Jules> has been far too low to actually be useful :-( I would think "it depends". Some home scanners have optical resolution of 4800 dpi or better. That may be good enough. Beware of inflated resolution figures. A lot of scanners have very high "resolution" claims but those are not real, they are fake pixels made by interpolation. Look for "optical" resolution, that's the real number. Also, in many cases there will be two numbers, e.g., 1200 x 4800; that means you have rectangular pixels, 1200 per inch in the coarse direction. You'd want a scanner where the smaller of the two optical resolution figures is large enough. How large is large enough? For a paper scan, 200 dpi is about the lowest you'd want, 300 is good. So that makes 3300 pixels for an 11 inch high sheet. So measure the page images on your fiche. They are probably the analog of 11 by 17 pages, so you'd want enough resolution to give you about 3000 pixels across the height of a page image. You'll also need a scanner with a "transparency" or "slide" capability. That means a back-light, typically built into the scanner lid. Those aren't all that common, though they are becoming more common these days. paul